draft-ietf-detnet-security-16.txt   rfc9055.txt 
Internet Engineering Task Force E. Grossman, Ed. Internet Engineering Task Force (IETF) E. Grossman, Ed.
Internet-Draft DOLBY Request for Comments: 9055 DOLBY
Intended status: Informational T. Mizrahi Category: Informational T. Mizrahi
Expires: September 3, 2021 HUAWEI ISSN: 2070-1721 HUAWEI
A. Hacker A. Hacker
MISTIQ THOUGHT
March 2, 2021 June 2021
Deterministic Networking (DetNet) Security Considerations Deterministic Networking (DetNet) Security Considerations
draft-ietf-detnet-security-16
Abstract Abstract
A DetNet (deterministic network) provides specific performance A DetNet (deterministic network) provides specific performance
guarantees to its data flows, such as extremely low data loss rates guarantees to its data flows, such as extremely low data loss rates
and bounded latency (including bounded latency variation, i.e. and bounded latency (including bounded latency variation, i.e.,
"jitter"). As a result, securing a DetNet requires that in addition "jitter"). As a result, securing a DetNet requires that in addition
to the best practice security measures taken for any mission-critical to the best practice security measures taken for any mission-critical
network, additional security measures may be needed to secure the network, additional security measures may be needed to secure the
intended operation of these novel service properties. intended operation of these novel service properties.
This document addresses DetNet-specific security considerations from This document addresses DetNet-specific security considerations from
the perspectives of both the DetNet system-level designer and the perspectives of both the DetNet system-level designer and
component designer. System considerations include a taxonomy of component designer. System considerations include a taxonomy of
relevant threats and attacks, and associations of threats versus use relevant threats and attacks, and associations of threats versus use
cases and service properties. Component-level considerations include cases and service properties. Component-level considerations include
ingress filtering and packet arrival time violation detection. ingress filtering and packet arrival-time violation detection.
This document also addresses security considerations specific to the This document also addresses security considerations specific to the
IP and MPLS data plane technologies, thereby complementing the IP and MPLS data plane technologies, thereby complementing the
Security Considerations sections of those documents. Security Considerations sections of those documents.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
Internet-Drafts are working documents of the Internet Engineering This document is a product of the Internet Engineering Task Force
Task Force (IETF). Note that other groups may also distribute (IETF). It represents the consensus of the IETF community. It has
working documents as Internet-Drafts. The list of current Internet- received public review and has been approved for publication by the
Drafts is at https://datatracker.ietf.org/drafts/current/. Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are candidates for any level of Internet
Standard; see Section 2 of RFC 7841.
Internet-Drafts are draft documents valid for a maximum of six months Information about the current status of this document, any errata,
and may be updated, replaced, or obsoleted by other documents at any and how to provide feedback on it may be obtained at
time. It is inappropriate to use Internet-Drafts as reference https://www.rfc-editor.org/info/rfc9055.
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 3, 2021.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction
2. Abbreviations and Terminology . . . . . . . . . . . . . . . . 7 2. Abbreviations and Terminology
3. Security Considerations for DetNet Component Design . . . . . 8 3. Security Considerations for DetNet Component Design
3.1. Resource Allocation . . . . . . . . . . . . . . . . . . . 8 3.1. Resource Allocation
3.1.1. Inviolable Flows . . . . . . . . . . . . . . . . . . 8 3.1.1. Inviolable Flows
3.1.2. Design Trade-Off Considerations in the Use Cases 3.1.2. Design Trade-Off Considerations in the Use Cases
Continuum . . . . . . . . . . . . . . . . . . . . . . 9 Continuum
3.1.3. Documenting the Security Properties of a Component . 10 3.1.3. Documenting the Security Properties of a Component
3.1.4. Fail-Safe Component Behavior . . . . . . . . . . . . 10 3.1.4. Fail-Safe Component Behavior
3.1.5. Flow Aggregation Example . . . . . . . . . . . . . . 10 3.1.5. Flow Aggregation Example
3.2. Explicit Routes . . . . . . . . . . . . . . . . . . . . . 11 3.2. Explicit Routes
3.3. Redundant Path Support . . . . . . . . . . . . . . . . . 11 3.3. Redundant Path Support
3.4. Timing (or other) Violation Reporting . . . . . . . . . . 12 3.4. Timing (or Other) Violation Reporting
4. DetNet Security Considerations Compared With DiffServ 4. DetNet Security Considerations Compared with Diffserv Security
Security Considerations . . . . . . . . . . . . . . . . . . . 13 Considerations
5. Security Threats . . . . . . . . . . . . . . . . . . . . . . 14 5. Security Threats
5.1. Threat Taxonomy . . . . . . . . . . . . . . . . . . . . . 15 5.1. Threat Taxonomy
5.2. Threat Analysis . . . . . . . . . . . . . . . . . . . . . 16 5.2. Threat Analysis
5.2.1. Delay . . . . . . . . . . . . . . . . . . . . . . . . 16 5.2.1. Delay
5.2.2. DetNet Flow Modification or Spoofing . . . . . . . . 16 5.2.2. DetNet Flow Modification or Spoofing
5.2.3. Resource Segmentation (Inter-segment Attack) 5.2.3. Resource Segmentation (Inter-segment Attack)
Vulnerability . . . . . . . . . . . . . . . . . . . . 16 Vulnerability
5.2.4. Packet Replication and Elimination . . . . . . . . . 17 5.2.4. Packet Replication and Elimination
5.2.4.1. Replication: Increased Attack Surface . . . . . . 17 5.2.4.1. Replication: Increased Attack Surface
5.2.4.2. Replication-related Header Manipulation . . . . . 17 5.2.4.2. Replication-Related Header Manipulation
5.2.5. Controller Plane . . . . . . . . . . . . . . . . . . 18 5.2.5. Controller Plane
5.2.5.1. Path Choice Manipulation . . . . . . . . . . . . 18 5.2.5.1. Path Choice Manipulation
5.2.5.2. Compromised Controller . . . . . . . . . . . . . 18 5.2.5.2. Compromised Controller
5.2.6. Reconnaissance . . . . . . . . . . . . . . . . . . . 19 5.2.6. Reconnaissance
5.2.7. Time Synchronization Mechanisms . . . . . . . . . . . 19 5.2.7. Time-Synchronization Mechanisms
5.3. Threat Summary . . . . . . . . . . . . . . . . . . . . . 19 5.3. Threat Summary
6. Security Threat Impacts . . . . . . . . . . . . . . . . . . . 20 6. Security Threat Impacts
6.1. Delay-Attacks . . . . . . . . . . . . . . . . . . . . . . 23 6.1. Delay Attacks
6.1.1. Data Plane Delay Attacks . . . . . . . . . . . . . . 23 6.1.1. Data Plane Delay Attacks
6.1.2. Controller Plane Delay Attacks . . . . . . . . . . . 23 6.1.2. Controller Plane Delay Attacks
6.2. Flow Modification and Spoofing . . . . . . . . . . . . . 23 6.2. Flow Modification and Spoofing
6.2.1. Flow Modification . . . . . . . . . . . . . . . . . . 24 6.2.1. Flow Modification
6.2.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . 24 6.2.2. Spoofing
6.2.2.1. Dataplane Spoofing . . . . . . . . . . . . . . . 24 6.2.2.1. Data Plane Spoofing
6.2.2.2. Controller Plane Spoofing . . . . . . . . . . . . 24 6.2.2.2. Controller Plane Spoofing
6.3. Segmentation Attacks (injection) . . . . . . . . . . . . 24 6.3. Segmentation Attacks (Injection)
6.3.1. Data Plane Segmentation . . . . . . . . . . . . . . . 25 6.3.1. Data Plane Segmentation
6.3.2. Controller Plane Segmentation . . . . . . . . . . . . 25 6.3.2. Controller Plane Segmentation
6.4. Replication and Elimination . . . . . . . . . . . . . . . 25 6.4. Replication and Elimination
6.4.1. Increased Attack Surface . . . . . . . . . . . . . . 26 6.4.1. Increased Attack Surface
6.4.2. Header Manipulation at Elimination Routers . . . . . 26 6.4.2. Header Manipulation at Elimination Routers
6.5. Control or Signaling Packet Modification . . . . . . . . 26 6.5. Control or Signaling Packet Modification
6.6. Control or Signaling Packet Injection . . . . . . . . . . 26 6.6. Control or Signaling Packet Injection
6.7. Reconnaissance . . . . . . . . . . . . . . . . . . . . . 26 6.7. Reconnaissance
6.8. Attacks on Time Synchronization Mechanisms . . . . . . . 27 6.8. Attacks on Time-Synchronization Mechanisms
6.9. Attacks on Path Choice . . . . . . . . . . . . . . . . . 27 6.9. Attacks on Path Choice
7. Security Threat Mitigation . . . . . . . . . . . . . . . . . 27 7. Security Threat Mitigation
7.1. Path Redundancy . . . . . . . . . . . . . . . . . . . . . 27 7.1. Path Redundancy
7.2. Integrity Protection . . . . . . . . . . . . . . . . . . 28 7.2. Integrity Protection
7.3. DetNet Node Authentication . . . . . . . . . . . . . . . 29 7.3. DetNet Node Authentication
7.4. Dummy Traffic Insertion . . . . . . . . . . . . . . . . . 30 7.4. Synthetic Traffic Insertion
7.5. Encryption . . . . . . . . . . . . . . . . . . . . . . . 31 7.5. Encryption
7.5.1. Encryption Considerations for DetNet . . . . . . . . 32 7.5.1. Encryption Considerations for DetNet
7.6. Control and Signaling Message Protection . . . . . . . . 33 7.6. Control and Signaling Message Protection
7.7. Dynamic Performance Analytics . . . . . . . . . . . . . . 33 7.7. Dynamic Performance Analytics
7.8. Mitigation Summary . . . . . . . . . . . . . . . . . . . 36 7.8. Mitigation Summary
8. Association of Attacks to Use Cases . . . . . . . . . . . . . 37 8. Association of Attacks to Use Cases
8.1. Association of Attacks to Use Case Common Themes . . . . 38 8.1. Association of Attacks to Use Case Common Themes
8.1.1. Sub-Network Layer . . . . . . . . . . . . . . . . . . 38 8.1.1. Sub-network Layer
8.1.2. Central Administration . . . . . . . . . . . . . . . 38 8.1.2. Central Administration
8.1.3. Hot Swap . . . . . . . . . . . . . . . . . . . . . . 38 8.1.3. Hot Swap
8.1.4. Data Flow Information Models . . . . . . . . . . . . 39 8.1.4. Data Flow Information Models
8.1.5. L2 and L3 Integration . . . . . . . . . . . . . . . . 39 8.1.5. L2 and L3 Integration
8.1.6. End-to-End Delivery . . . . . . . . . . . . . . . . . 40 8.1.6. End-to-End Delivery
8.1.7. Replacement for Proprietary Fieldbuses and Ethernet- 8.1.7. Replacement for Proprietary Fieldbuses and
based Networks . . . . . . . . . . . . . . . . . . . 40 Ethernet-Based Networks
8.1.8. Deterministic vs Best-Effort Traffic . . . . . . . . 41 8.1.8. Deterministic vs. Best-Effort Traffic
8.1.9. Deterministic Flows . . . . . . . . . . . . . . . . . 42 8.1.9. Deterministic Flows
8.1.10. Unused Reserved Bandwidth . . . . . . . . . . . . . . 42 8.1.10. Unused Reserved Bandwidth
8.1.11. Interoperability . . . . . . . . . . . . . . . . . . 42 8.1.11. Interoperability
8.1.12. Cost Reductions . . . . . . . . . . . . . . . . . . . 43 8.1.12. Cost Reductions
8.1.13. Insufficiently Secure Components . . . . . . . . . . 43 8.1.13. Insufficiently Secure Components
8.1.14. DetNet Network Size . . . . . . . . . . . . . . . . . 43 8.1.14. DetNet Network Size
8.1.15. Multiple Hops . . . . . . . . . . . . . . . . . . . . 44 8.1.15. Multiple Hops
8.1.16. Level of Service . . . . . . . . . . . . . . . . . . 44 8.1.16. Level of Service
8.1.17. Bounded Latency . . . . . . . . . . . . . . . . . . . 45 8.1.17. Bounded Latency
8.1.18. Low Latency . . . . . . . . . . . . . . . . . . . . . 45 8.1.18. Low Latency
8.1.19. Bounded Jitter (Latency Variation) . . . . . . . . . 45 8.1.19. Bounded Jitter (Latency Variation)
8.1.20. Symmetrical Path Delays . . . . . . . . . . . . . . . 45 8.1.20. Symmetrical Path Delays
8.1.21. Reliability and Availability . . . . . . . . . . . . 46 8.1.21. Reliability and Availability
8.1.22. Redundant Paths . . . . . . . . . . . . . . . . . . . 46 8.1.22. Redundant Paths
8.1.23. Security Measures . . . . . . . . . . . . . . . . . . 46 8.1.23. Security Measures
8.2. Summary of Attack Types per Use Case Common Theme . . . . 47 8.2. Summary of Attack Types per Use Case Common Theme
9. Security Considerations for OAM Traffic . . . . . . . . . . . 49 9. Security Considerations for OAM Traffic
10. DetNet Technology-Specific Threats . . . . . . . . . . . . . 49 10. DetNet Technology-Specific Threats
10.1. IP . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 10.1. IP
10.2. MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10.2. MPLS
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52 11. IANA Considerations
12. Security Considerations . . . . . . . . . . . . . . . . . . . 52 12. Security Considerations
13. Privacy Considerations . . . . . . . . . . . . . . . . . . . 52 13. Privacy Considerations
14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 53 14. References
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 53 14.1. Normative References
15.1. Normative References . . . . . . . . . . . . . . . . . . 53 14.2. Informative References
15.2. Informative References . . . . . . . . . . . . . . . . . 54 Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 59 Authors' Addresses
1. Introduction 1. Introduction
A deterministic IP network (IETF DetNet, [RFC8655]) can carry data A deterministic IP network ("Deterministic Networking Architecture"
flows for real-time applications with extremely low data loss rates [RFC8655]) can carry data flows for real-time applications with
and bounded latency. The bounds on latency defined by DetNet (as extremely low data loss rates and bounded latency. The bounds on
described in [I-D.ietf-detnet-flow-information-model]) include both latency defined by DetNet (as described in [RFC9016]) include both
worst case latency (Maximum Latency, Section 5.9.2) and worst case worst-case latency (Maximum Latency, Section 5.9.2 of [RFC9016]) and
jitter (Maximum Latency Variation, Section 5.9.3). Data flows with worst-case jitter (Maximum Latency Variation, Section 5.9.3 of
deterministic properties are well-established for Ethernet networks [RFC9016]). Data flows with deterministic properties are well
(see TSN, [IEEE802.1BA]); DetNet brings these capabilities to the IP established for Ethernet networks (see Time-Sensitive Networking
(TSN), [IEEE802.1BA]); DetNet brings these capabilities to the IP
network. network.
Deterministic IP networks have been successfully deployed in real- Deterministic IP networks have been successfully deployed in real-
time Operational Technology (OT) applications for some years, however time Operational Technology (OT) applications for some years;
such networks are typically isolated from external access, and thus however, such networks are typically isolated from external access,
the security threat from external attackers is low. An example of and thus the security threat from external attackers is low. An
such an isolated network is a network deployed within an aircraft, example of such an isolated network is a network deployed within an
which is "air gapped" from the outside world. DetNet specifies a set aircraft, which is "air gapped" from the outside world. DetNet
of technologies that enable creation of deterministic flows on IP- specifies a set of technologies that enable creation of deterministic
based networks of potentially wide area (on the scale of a corporate flows on IP-based networks of a potentially wide area (on the scale
network), potentially merging OT traffic with best-effort of a corporate network), potentially merging OT traffic with best-
(Information Technology, IT) traffic, and placing OT network effort Information Technology (IT) traffic, and placing OT network
components into contact with IT network components, thereby exposing components into contact with IT network components, thereby exposing
the OT traffic and components to security threats that were not the OT traffic and components to security threats that were not
present in an isolated OT network. present in an isolated OT network.
These DetNet (OT-type) technologies may not have previously been These DetNet (OT-type) technologies may not have previously been
deployed on a wide area IP-based network that also carries IT deployed on a wide area IP-based network that also carries IT
traffic, and thus can present security considerations that may be new traffic, and thus they can present security considerations that may
to IP-based wide area network designers; this document provides be new to IP-based wide area network designers; this document
insight into such system-level security considerations. In addition, provides insight into such system-level security considerations. In
designers of DetNet components (such as routers) face new security- addition, designers of DetNet components (such as routers) face new
related challenges in providing DetNet services, for example security-related challenges in providing DetNet services, for
maintaining reliable isolation between traffic flows in an example, maintaining reliable isolation between traffic flows in an
environment where IT traffic co-mingles with critical reserved- environment where IT traffic co-mingles with critical reserved-
bandwidth OT traffic; this document also examines security bandwidth OT traffic; this document also examines security
implications internal to DetNet components. implications internal to DetNet components.
Security is of particularly high importance in DetNet because many of Security is of particularly high importance in DetNet because many of
the use cases which are enabled by DetNet [RFC8578] include control the use cases that are enabled by DetNet [RFC8578] include control of
of physical devices (power grid devices, industrial controls, physical devices (power grid devices, industrial controls, building
building controls) which can have high operational costs for failure, controls, etc.) that can have high operational costs for failure and
and present potentially attractive targets for cyber-attackers. present potentially attractive targets for cyber attackers.
This situation is even more acute given that one of the goals of This situation is even more acute given that one of the goals of
DetNet is to provide a "converged network", i.e. one that includes DetNet is to provide a "converged network", i.e., one that includes
both IT traffic and OT traffic, thus exposing potentially sensitive both IT traffic and OT traffic, thus exposing potentially sensitive
OT devices to attack in ways that were not previously common (usually OT devices to attack in ways that were not previously common (usually
because they were under a separate control system or otherwise because they were under a separate control system or otherwise
isolated from the IT network, for example [ARINC664P7]). Security isolated from the IT network, for example [ARINC664P7]). Security
considerations for OT networks are not a new area, and there are many considerations for OT networks are not a new area, and there are many
OT networks today that are connected to wide area networks or the OT networks today that are connected to wide area networks or the
Internet; this document focuses on the issues that are specific to Internet; this document focuses on the issues that are specific to
the DetNet technologies and use cases. the DetNet technologies and use cases.
Given the above considerations, securing a DetNet starts with a Given the above considerations, securing a DetNet starts with a
scrupulously well-designed and well-managed engineered network scrupulously well-designed and well-managed engineered network
following industry best practices for security at both the data plane following industry best practices for security at both the data plane
and controller plane, as well as for any OAM implementation; this is and controller plane, as well as for any Operations, Administration,
the assumed starting point for the considerations discussed herein. and Maintenance (OAM) implementation; this is the assumed starting
Such assumptions also depend on the network components themselves point for the considerations discussed herein. Such assumptions also
upholding the security-related properties that are to be assumed by depend on the network components themselves upholding the security-
DetNet system-level designers; for example, the assumption that related properties that are to be assumed by DetNet system-level
network traffic associated with a given flow can never affect traffic designers; for example, the assumption that network traffic
associated with a different flow is only true if the underlying associated with a given flow can never affect traffic associated with
components make it so. Such properties, which may represent new a different flow is only true if the underlying components make it
challenges to component designers, are also considered herein. so. Such properties, which may represent new challenges to component
designers, are also considered herein.
Starting with a "well-managed network" as noted above enables us to Starting with a "well-managed network", as noted above, enables us to
exclude some of the more powerful adversary capabilities from the exclude some of the more powerful adversary capabilities from the
Internet Threat Model of BCP 72 ([RFC3552]), such as the ability to Internet Threat Model of [BCP72], such as the ability to arbitrarily
arbitrarily drop or delay any or all traffic. Given this reduced drop or delay any or all traffic. Given this reduced attacker
attacker capability, we can present security considerations based on capability, we can present security considerations based on attacker
attacker capabilities that are more directly relevant to a DetNet. capabilities that are more directly relevant to a DetNet.
In this context we view the "traditional" (i.e. non-time-sensitive) In this context, we view the "conventional" (i.e., non-time-
network design and management aspects of network security as being sensitive) network design and management aspects of network security
primarily concerned with denial-of service prevention, i.e. they must as being primarily concerned with preventing denial of service, i.e.,
ensure that DetNet traffic goes where it's supposed to and that an they must ensure that DetNet traffic goes where it's supposed to and
external attacker can't inject traffic that disrupts the delivery that an external attacker can't inject traffic that disrupts the
timing assurance of the DetNet. The time-specific aspects of DetNet delivery timing assurance of the DetNet. The time-specific aspects
security presented here take up where those "traditional" design and of DetNet security presented here take up where those "conventional"
management aspects leave off. design and management aspects leave off.
However note that "traditional" methods for mitigating (among all the However, note that "conventional" methods for mitigating (among all
others) denial-of service attack (such as throttling) can only be the others) denial-of-service attacks (such as throttling) can only
effectively used in a DetNet when their use does not compromise the be effectively used in a DetNet when their use does not compromise
required time-sensitive or behavioral properties required for the OT the required time-sensitive or behavioral properties required for the
flows on the network. For example, a "retry" protocol is typically OT flows on the network. For example, a "retry" protocol is
not going to be compatible with a low-latency (worst-case maximum typically not going to be compatible with a low-latency (worst-case
latency) requirement, however if in a specific use case and maximum latency) requirement; however, if in a specific use case and
implementation such a retry protocol is able to meet the timing implementation such a retry protocol is able to meet the timing
constraints, then it may well be used in that context. Similarly if constraints, then it may well be used in that context. Similarly, if
common security protocols such as TLS/DTLS or IPsec are to be used, common security protocols such as TLS/DTLS or IPsec are to be used,
it must be verified that their implementations are able to meet the it must be verified that their implementations are able to meet the
timing and behavioral requirements of the time-sensitive network as timing and behavioral requirements of the time-sensitive network as
implemented for the given use case. An example of "behavioral implemented for the given use case. An example of "behavioral
properties" might be that dropping of more than a specific number of properties" might be that dropping of more than a specific number of
packets in a row is not acceptable according to the service level packets in a row is not acceptable according to the service level
agreement. agreement.
The exact security requirements for any given DetNet are necessarily The exact security requirements for any given DetNet are necessarily
specific to the use cases handled by that network. Thus the reader specific to the use cases handled by that network. Thus, the reader
is assumed to be familiar with the specific security requirements of is assumed to be familiar with the specific security requirements of
their use cases, for example those outlined in the DetNet Use Cases their use cases, for example, those outlined in the DetNet Use Cases
[RFC8578] and the Security Considerations sections of the DetNet [RFC8578] and the Security Considerations sections of the DetNet
documents applicable to the network technologies in use, for example documents applicable to the network technologies in use, for example,
[RFC8939] for an IP data plane and [RFC8964] for an MPLS data plane. [RFC8939] for an IP data plane and [RFC8964] for an MPLS data plane.
Readers can find a general introduction to the DetNet Architecture in Readers can find a general introduction to the DetNet Architecture in
[RFC8655], the DetNet Data Plane in [RFC8938], and the Flow [RFC8655], the DetNet Data Plane in [RFC8938], and the Flow
Information Model in [I-D.ietf-detnet-flow-information-model]. Information Model in [RFC9016].
The DetNet technologies include ways to: The DetNet technologies include ways to:
o Assign data plane resources for DetNet flows in some or all of the * Assign data plane resources for DetNet flows in some or all of the
intermediate nodes (routers) along the path of the flow intermediate nodes (routers) along the path of the flow
o Provide explicit routes for DetNet flows that do not dynamically * Provide explicit routes for DetNet flows that do not dynamically
change with the network topology in ways that affect the quality change with the network topology in ways that affect the quality
of service received by the affected flow(s) of service received by the affected flow(s)
o Distribute data from DetNet flow packets over time and/or space to * Distribute data from DetNet flow packets over time and/or space to
ensure delivery of the data in each packet in spite of the loss of ensure delivery of the data in each packet in spite of the loss of
a path. a path
This document includes sections considering DetNet component design This document includes sections considering DetNet component design
as well as system design. The latter includes a taxonomy and as well as system design. The latter includes a taxonomy and
analysis of threats, threat impacts and mitigations, and an analysis of threats, threat impacts and mitigations, and an
association of attacks with use cases (based on the Use Case Common association of attacks with use cases (based on Section 11 of
Themes section of the DetNet Use Cases [RFC8578]). [RFC8578]).
This document is based on the premise that there will be a very broad This document is based on the premise that there will be a very broad
range of DetNet applications and use cases, ranging in size and scope range of DetNet applications and use cases, ranging in size and scope
from individual industrial machines to networks that span an entire from individual industrial machines to networks that span an entire
country ([RFC8578]). Thus no single set of prescriptions (such as country [RFC8578]. Thus, no single set of prescriptions (such as
exactly which mitigation should be applied to which segment of a exactly which mitigation should be applied to which segment of a
DetNet) can be applicable to all of them, and indeed any single one DetNet) can be applicable to all of them, and indeed any single one
that we might prescribe would inevitably prove impractical for some that we might prescribe would inevitably prove impractical for some
use case, perhaps one that does not even exist at the time of this use case, perhaps one that does not even exist at the time of this
writing. Thus we are not prescriptive here - we are stating the writing. Thus, we are not prescriptive here; we are stating the
desired end result, with the understanding that most DetNet use cases desired end result, with the understanding that most DetNet use cases
will necessarily differ from each other, and there is no "one size will necessarily differ from each other, and there is no "one size
fits all". fits all".
2. Abbreviations and Terminology 2. Abbreviations and Terminology
IT: Information Technology (the application of computers to store, Information Technology (IT): The application of computers to store,
study, retrieve, transmit, and manipulate data or information, often study, retrieve, transmit, and manipulate data or information,
in the context of a business or other enterprise - [IT_DEF]). often in the context of a business or other enterprise [IT-DEF].
OT: Operational Technology (the hardware and software dedicated to Operational Technology (OT): The hardware and software dedicated to
detecting or causing changes in physical processes through direct detecting or causing changes in physical processes through direct
monitoring and/or control of physical devices such as valves, pumps, monitoring and/or control of physical devices such as valves,
etc. - [OT_DEF]) pumps, etc. [OT-DEF].
Component: A component of a DetNet system - used here to refer to any Component: A component of a DetNet system -- used here to refer to
hardware or software element of a DetNet which implements DetNet- any hardware or software element of a DetNet that implements
specific functionality, for example all or part of a router, switch, DetNet-specific functionality, for example, all or part of a
or end system. router, switch, or end system.
Device: Used here to refer to a physical entity controlled by the Device: Used here to refer to a physical entity controlled by the
DetNet, for example a motor. DetNet, for example, a motor.
Resource Segmentation: Used as a more general form for Network Resource Segmentation: Used as a more general form for Network
Segmentation (the act or practice of splitting a computer network Segmentation (the act or practice of splitting a computer network
into subnetworks, each being a network segment - [RS_DEF]) into sub-networks, each being a network segment [NS-DEF]).
Controller Plane: In DetNet the Controller Plane corresponds to the Controller Plane: In DetNet, the Controller Plane corresponds to the
aggregation of the Control and Management Planes (see [RFC8655] aggregation of the Control and Management Planes (see [RFC8655],
section 4.4.2). Section 4.4.2).
3. Security Considerations for DetNet Component Design 3. Security Considerations for DetNet Component Design
This section provides guidance for implementers of components to be This section provides guidance for implementers of components to be
used in a DetNet. used in a DetNet.
As noted above, DetNet provides resource allocation, explicit routes As noted above, DetNet provides resource allocation, explicit routes,
and redundant path support. Each of these has associated security and redundant path support. Each of these has associated security
implications, which are discussed in this section, in the context of implications, which are discussed in this section, in the context of
component design. Detection, reporting and appropriate action in the component design. Detection, reporting and appropriate action in the
case of packet arrival time violations are also discussed. case of packet arrival-time violations are also discussed.
3.1. Resource Allocation 3.1. Resource Allocation
3.1.1. Inviolable Flows 3.1.1. Inviolable Flows
A DetNet system security designer relies on the premise that any A DetNet system security designer relies on the premise that any
resources allocated to a resource-reserved (OT-type) flow are resources allocated to a resource-reserved (OT-type) flow are
inviolable; in other words there is no physical possibility within a inviolable; in other words, there is no physical possibility within a
DetNet component that resources allocated to a given DetNet flow can DetNet component that resources allocated to a given DetNet flow can
be compromised by any type of traffic in the network; this includes be compromised by any type of traffic in the network. This includes
malicious traffic as well as inadvertent traffic such as might be malicious traffic as well as inadvertent traffic such as might be
produced by a malfunctioning component, or due to interactions produced by a malfunctioning component, or due to interactions
between components that were not sufficiently tested for between components that were not sufficiently tested for
interoperability. From a security standpoint this is a critical interoperability. From a security standpoint, this is a critical
assumption, for example when designing against DOS attacks. In other assumption, for example, when designing against DoS attacks. In
words, with correctly designed components and security mechanisms, other words, with correctly designed components and security
one can prevent malicious activities from impacting other resources. mechanisms, one can prevent malicious activities from impacting other
resources.
However, achieving the goal of absolutely inviolable flows may not be However, achieving the goal of absolutely inviolable flows may not be
technically or economically feasible for any given use case, given technically or economically feasible for any given use case, given
the broad range of possible use cases (e.g. [reference to DetNet Use the broad range of possible use cases (e.g., [RFC8578]) and their
Cases RFC8578]) and their associated security considerations as associated security considerations as outlined in this document. It
outlined in this document. It can be viewed as a continuum of can be viewed as a continuum of security requirements, from isolated
security requirements, from isolated ultra-low latency systems that ultra-low latency systems that may have little security vulnerability
may have little security vulnerability (such as an industrial (such as an industrial machine) to broadly distributed systems with
machine) to broadly distributed systems with many possible attack many possible attack vectors and OT security concerns (such as a
vectors and OT security concerns (such as a utility network). Given utility network). Given this continuum, the design principle
this continuum, the design principle employed in this document is to employed in this document is to specify the desired end results,
specify the desired end results, without being overly prescriptive in without being overly prescriptive in how the results are achieved,
how the results are achieved, reflecting the understanding that no reflecting the understanding that no individual implementation is
individual implementation is likely to be appropriate for every likely to be appropriate for every DetNet use case.
DetNet use case.
3.1.2. Design Trade-Off Considerations in the Use Cases Continuum 3.1.2. Design Trade-Off Considerations in the Use Cases Continuum
It is important for the DetNet system designer to understand, for any For any given DetNet use case and its associated security
given DetNet use case and its associated security requirements, the requirements, it is important for the DetNet system designer to
interaction and design trade-offs that inevitably need to be understand the interaction and design trade-offs that inevitably need
reconciled between the desired end results and the DetNet protocols, to be reconciled between the desired end results and the DetNet
as well as the DetNet system and component design. protocols, as well as the DetNet system and component design.
For any given component, as designed for any given use case (or scope For any given component, as designed for any given use case (or scope
of use cases), it is the responsibility of the component designer to of use cases), it is the responsibility of the component designer to
ensure that the premise of inviolable flows is supported, to the ensure that the premise of inviolable flows is supported to the
extent that they deem necessary to support their target use cases. extent that they deem necessary to support their target use cases.
For example, the component may include traffic shaping and policing For example, the component may include traffic shaping and policing
at the ingress, to prevent corrupted or malicious or excessive at the ingress to prevent corrupted, malicious, or excessive packets
packets from entering the network, thereby decreasing the likelihood from entering the network, thereby decreasing the likelihood that any
that any traffic will interfere with any DetNet OT flow. The traffic will interfere with any DetNet OT flow. The component may
component may include integrity protection for some or all of the include integrity protection for some or all of the header fields
header fields such as those used for flow ID, thereby decreasing the such as those used for flow ID, thereby decreasing the likelihood
likelihood that a packet whose flow ID has been compromised might be that a packet whose flow ID has been compromised might be directed
directed into a different flow path. The component may verify every into a different flow path. The component may verify every single
single packet header at every forwarding location, or only at certain packet header at every forwarding location, or only at certain
points. In any of these cases the component may use dynamic points. In any of these cases, the component may use dynamic
performance analytics (Section 7.7) to cause action to be initiated performance analytics (Section 7.7) to cause action to be initiated
to address the situation in an appropriate and timely manner, either to address the situation in an appropriate and timely manner, either
at the data plane or controller plane, or both in concert. The at the data plane or controller plane, or both in concert. The
component's software and hardware may include measures to ensure the component's software and hardware may include measures to ensure the
integrity of the resource allocation/deallocation process. Other integrity of the resource allocation/deallocation process. Other
design aspects of the component may help ensure that the adverse design aspects of the component may help ensure that the adverse
effects of malicious traffic are more limited, for example by effects of malicious traffic are more limited, for example, by
protecting network control interfaces, or minimizing cascade protecting network control interfaces or minimizing cascade failures.
failures. The component may include features specific to a given use The component may include features specific to a given use case, such
case, such as configuration of the response to a given sequential as configuration of the response to a given sequential packet loss
packet loss count. count.
Ultimately, due to cost and complexity factors, the security Ultimately, due to cost and complexity factors, the security
properties of a component designed for low-cost systems may be (by properties of a component designed for low-cost systems may be (by
design) far inferior to a component with similar intended design) far inferior to a component with similar intended
functionality, but designed for highly secure or otherwise critical functionality, but designed for highly secure or otherwise critical
applications, perhaps at substantially higher cost. Any given applications, perhaps at substantially higher cost. Any given
component is designed for some set of use cases and accordingly will component is designed for some set of use cases and accordingly will
have certain limitations on its security properties and have certain limitations on its security properties and
vulnerabilities. It is thus the responsibility of the system vulnerabilities. It is thus the responsibility of the system
designer to assure themselves that the components they use in their designer to assure themselves that the components they use in their
design are capable of satisfying their overall system security design are capable of satisfying their overall system security
requirements. requirements.
3.1.3. Documenting the Security Properties of a Component 3.1.3. Documenting the Security Properties of a Component
In order for the system designer to adequately understand the In order for the system designer to adequately understand the
security related behavior of a given component, the designer of any security-related behavior of a given component, the designer of any
component intended for use with DetNet needs to clearly document the component intended for use with DetNet needs to clearly document the
security properties of that component. For example, to address the security properties of that component. For example, to address the
case where a corrupted packet in which the flow identification case where a corrupted packet in which the flow identification
information is compromised and thus may incidentally match the flow information is compromised and thus may incidentally match the flow
ID of another ("victim") DetNet flow, resulting in additional ID of another ("victim") DetNet flow, resulting in additional
unauthorized traffic on the victim, the documentation might state unauthorized traffic on the victim, the documentation might state
that the component employs integrity protection on the flow that the component employs integrity protection on the flow
identification fields. identification fields.
3.1.4. Fail-Safe Component Behavior 3.1.4. Fail-Safe Component Behavior
Even when the security properties of a component are understood and Even when the security properties of a component are understood and
well specified, if the component malfunctions, for example due to well specified, if the component malfunctions, for example, due to
physical circumstances unpredicted by the component designer, it may physical circumstances unpredicted by the component designer, it may
be difficult or impossible to fully prevent malfunction of the be difficult or impossible to fully prevent malfunction of the
network. The degree to which a component is hardened against various network. The degree to which a component is hardened against various
types of failures is a distinguishing feature of the component and types of failures is a distinguishing feature of the component and
its design, and the overall system design can only be as strong as its design, and the overall system design can only be as strong as
its weakest link. its weakest link.
However, all networks are subject to this level of uncertainty; it is However, all networks are subject to this level of uncertainty; it is
not unique to DetNet. Having said that, DetNet raises the bar by not unique to DetNet. Having said that, DetNet raises the bar by
changing many added latency scenarios from tolerable annoyances to changing many added latency scenarios from tolerable annoyances to
unacceptable service violations. That in turn underscores the unacceptable service violations. That in turn underscores the
importance of system integrity, as well as correct and stable importance of system integrity, as well as correct and stable
configuration of the network and its nodes, as discussed in configuration of the network and its nodes, as discussed in
Section 1. Section 1.
3.1.5. Flow Aggregation Example 3.1.5. Flow Aggregation Example
As another example regarding resource allocation implementation, As another example regarding resource allocation implementation,
consider the implementation of Flow Aggregation for DetNet flows (as consider the implementation of Flow Aggregation for DetNet flows (as
discussed in [RFC8938]). In this example say there are N flows that discussed in [RFC8938]). In this example, say there are N flows that
are to be aggregated, thus the bandwidth resources of the aggregate are to be aggregated; thus, the bandwidth resources of the aggregate
flow must be sufficient to contain the sum of the bandwidth flow must be sufficient to contain the sum of the bandwidth
reservation for the N flows. However if one of those flows were to reservation for the N flows. However, if one of those flows were to
consume more than its individually allocated bandwidth, this could consume more than its individually allocated bandwidth, this could
cause starvation of the other flows. Thus simply providing and cause starvation of the other flows. Thus, simply providing and
enforcing the calculated aggregate bandwidth may not be a complete enforcing the calculated aggregate bandwidth may not be a complete
solution - the bandwidth for each individual flow must still be solution; the bandwidth for each individual flow must still be
guaranteed, for example via ingress policing of each flow (i.e. guaranteed, for example, via ingress policing of each flow (i.e.,
before it is aggregated). Alternatively, if by some other means each before it is aggregated). Alternatively, if by some other means each
flow to be aggregated can be trusted not to exceed its allocated flow to be aggregated can be trusted not to exceed its allocated
bandwidth, the same goal can be achieved. bandwidth, the same goal can be achieved.
3.2. Explicit Routes 3.2. Explicit Routes
The DetNet-specific purpose for constraining the ability of the The DetNet-specific purpose for constraining the ability of the
DetNet to re-route OT traffic is to maintain the specified service DetNet to reroute OT traffic is to maintain the specified service
parameters (such as upper and lower latency boundaries) for a given parameters (such as upper and lower latency boundaries) for a given
flow. For example if the network were to re-route a flow (or some flow. For example, if the network were to reroute a flow (or some
part of a flow) based exclusively on statistical path usage metrics, part of a flow) based exclusively on statistical path usage metrics,
or due to malicious activity, it is possible that the new path would or due to malicious activity, it is possible that the new path would
have a latency that is outside the required latency bounds which were have a latency that is outside the required latency bounds that were
designed into the original TE-designed path, thereby violating the designed into the original TE-designed path, thereby violating the
quality of service for the affected flow (or part of that flow). quality of service for the affected flow (or part of that flow).
However, it is acceptable for the network to re-route OT traffic in However, it is acceptable for the network to reroute OT traffic in
such a way as to maintain the specified latency bounds (and any other such a way as to maintain the specified latency bounds (and any other
specified service properties) for any reason, for example in response specified service properties) for any reason, for example, in
to a runtime component or path failure. response to a runtime component or path failure.
So from a DetNet security standpoint, the DetNet system designer can So from a DetNet security standpoint, the DetNet system designer can
expect that any component designed for use in a DetNet will deliver expect that any component designed for use in a DetNet will deliver
the packets within the agreed-upon service parameters. For the the packets within the agreed-upon service parameters. For the
component designer, this means that in order for a component to component designer, this means that in order for a component to
achieve that expectation, any component that is involved in achieve that expectation, any component that is involved in
controlling or implementing any change of the initially TE-configured controlling or implementing any change of the initially TE-configured
flow routes must prevent re-routing of OT flows (whether malicious or flow routes must prevent rerouting of OT flows (whether malicious or
accidental) which might adversely affect delivering the traffic accidental) that might adversely affect delivering the traffic within
within the specified service parameters. the specified service parameters.
3.3. Redundant Path Support 3.3. Redundant Path Support
The DetNet provision for redundant paths (PREOF) (as defined in the The DetNet provision for redundant paths (i.e., PREOF, or "Packet
DetNet Architecture [RFC8655]) provides the foundation for high Replication, Elimination, and Ordering Functions"), as defined in the
reliability of a DetNet, by virtually eliminating packet loss (i.e. DetNet Architecture [RFC8655], provides the foundation for high
to a degree which is implementation-dependent) through hitless reliability of a DetNet by virtually eliminating packet loss (i.e.,
redundant packet delivery. Note: At the time of this writing, PREOF to a degree that is implementation dependent) through hitless
is not defined for the IP data plane. redundant packet delivery.
| Note: At the time of this writing, PREOF is not defined for the
| IP data plane.
It is the responsibility of the system designer to determine the It is the responsibility of the system designer to determine the
level of reliability required by their use case, and to specify level of reliability required by their use case and to specify
redundant paths sufficient to provide the desired level of redundant paths sufficient to provide the desired level of
reliability (in as much as that reliability can be provided through reliability (in as much as that reliability can be provided through
the use of redundant paths). It is the responsibility of the the use of redundant paths). It is the responsibility of the
component designer to ensure that the relevant PREOF operations are component designer to ensure that the relevant PREOF operations are
executed reliably and securely, to avoid potentially catastrophic executed reliably and securely to avoid potentially catastrophic
situations for the operational technology relying on them. situations for the operational technology relying on them.
However, note that not all PREOF operations are necessarily However, note that not all PREOF operations are necessarily
implemented in every network; for example a packet re-ordering implemented in every network; for example, a packet reordering
function may not be necessary if the packets are either not required function may not be necessary if the packets are either not required
to be in order, or if the ordering is performed in some other part of to be in order or if the ordering is performed in some other part of
the network. the network.
Ideally a redundant path for a flow could be specified from end to Ideally, a redundant path for a flow could be specified from end to
end, however given that this is not always possible (as described in end; however, given that this is not always possible (as described in
[RFC8655]) the system designer will need to consider the resulting [RFC8655]), the system designer will need to consider the resulting
end-to-end reliability and security resulting from any given end-to-end reliability and security resulting from any given
arrangement of network segments along the path, each of which arrangement of network segments along the path, each of which
provides its individual PREOF implementation and thus its individual provides its individual PREOF implementation and thus its individual
level of reliability and security. level of reliability and security.
At the data plane the implementation of PREOF depends on the correct At the data plane, the implementation of PREOF depends on the correct
assignment and interpretation of packet sequence numbers, as well as assignment and interpretation of packet sequence numbers, as well as
the actions taken based on them, such as elimination (including the actions taken based on them, such as elimination (including
elimination of packets with spurious sequence numbers). Thus the elimination of packets with spurious sequence numbers). Thus, the
integrity of these values must be maintained by the component as they integrity of these values must be maintained by the component as they
are assigned by the DetNet Data Plane Service sub-layer, and are assigned by the DetNet Data Plane Service sub-layer and
transported by the Forwarding sub-layer. This is no different than transported by the Forwarding sub-layer. This is no different than
the integrity of the values in any header used by the DetNet (or any the integrity of the values in any header used by the DetNet (or any
other) data plane, and is not unique to redundant paths. The other) data plane and is not unique to redundant paths. The
integrity protection of header values is technology-dependent; for integrity protection of header values is technology dependent; for
example, in Layer 2 networks the integrity of the header fields can example, in Layer 2 networks, the integrity of the header fields can
be protected by using MACsec [IEEE802.1AE-2018]. Similarly, from the be protected by using MACsec [IEEE802.1AE-2018]. Similarly, from the
sequence number injection perspective, it is no different from any sequence number injection perspective, it is no different from any
other protocols that use sequence numbers. In particular IPSec other protocols that use sequence numbers; for particulars of
Authentication Header ([RFC4302], Sec. 3 Authentication Header (AH) integrity protection via IPsec Authentication Headers, useful
Processing) provides useful insights. insights are provided by Section 3 of [RFC4302].
3.4. Timing (or other) Violation Reporting 3.4. Timing (or Other) Violation Reporting
A task of the DetNet system designer is to create a network such that A task of the DetNet system designer is to create a network such that
for any incoming packet which arrives with any timing or bandwidth for any incoming packet that arrives with any timing or bandwidth
violation, an appropriate action can be taken in order to prevent violation, an appropriate action can be taken in order to prevent
damage to the system. The reporting step may be accomplished through damage to the system. The reporting step may be accomplished through
dynamic performance analysis (see Section 7.7) or by any other means dynamic performance analysis (see Section 7.7) or by any other means
as implemented in one or more components. The action to be taken for as implemented in one or more components. The action to be taken for
any given circumstance within any given application will depend on any given circumstance within any given application will depend on
the use case. The action may involve intervention from the the use case. The action may involve intervention from the
controller plane, or it may be taken "immediately" by an individual controller plane, or it may be taken "immediately" by an individual
component, for example if very fast response is required. component, for example, if a very fast response is required.
The definitions and selections of the actions that can be taken are The definitions and selections of the actions that can be taken are
properties of the components. The component designer implements properties of the components. The component designer implements
these options according to their expected use cases, which may vary these options according to their expected use cases, which may vary
widely from component to component. Clearly selecting an widely from component to component. Clearly, selecting an
inappropriate response to a given condition may cause more problems inappropriate response to a given condition may cause more problems
than it is intending to mitigate; for example, a naive approach might than it is intending to mitigate; for example, a naive approach might
be to have the component shut down the link if a packet arrives be to have the component shut down the link if a packet arrives
outside of its prescribed time window; however such a simplistic outside of its prescribed time window. However, such a simplistic
action may serve the attacker better than it serves the network. action may serve the attacker better than it serves the network.
Similarly, simple logging of such issues may not be adequate, since a Similarly, simple logging of such issues may not be adequate since a
delay in response could result in material damage, for example to delay in response could result in material damage, for example, to
mechanical devices controlled by the network. Thus a breadth of mechanical devices controlled by the network. Thus, a breadth of
possible and effective security-related actions and their possible and effective security-related actions and their
configuration is a positive attribute for a DetNet component. configuration is a positive attribute for a DetNet component.
Some possible violations that warrant detection include cases where a Some possible violations that warrant detection include cases where a
packet arrives: packet arrives:
o Outside of its prescribed time window * Outside of its prescribed time window
o Within its time window but with a compromised time stamp that * Within its time window but with a compromised timestamp that makes
makes it appear that it is not within its window it appear that it is not within its window
o Exceeding the reserved flow bandwidth * Exceeding the reserved flow bandwidth
Some possible direct actions that may be taken at the data plane Some possible direct actions that may be taken at the data plane
include traffic policing and shaping functions (e.g., those described include traffic policing and shaping functions (e.g., those described
in [RFC2475]), separating flows into per-flow rate-limited queues, in [RFC2475]), separating flows into per-flow rate-limited queues,
and potentially applying active queue management [RFC7567]. However and potentially applying active queue management [RFC7567]. However,
if those (or any other) actions are to be taken, the system designer if those (or any other) actions are to be taken, the system designer
must ensure that the results of such actions do not compromise the must ensure that the results of such actions do not compromise the
continued safe operation of the system. For example, the network continued safe operation of the system. For example, the network
(i.e. the controller plane and data plane working together) must (i.e., the controller plane and data plane working together) must
mitigate in a timely fashion any potential adverse effect on mitigate in a timely fashion any potential adverse effect on
mechanical devices controlled by the network. mechanical devices controlled by the network.
4. DetNet Security Considerations Compared With DiffServ Security 4. DetNet Security Considerations Compared with Diffserv Security
Considerations Considerations
DetNet is designed to be compatible with DiffServ [RFC2474] as DetNet is designed to be compatible with Diffserv [RFC2474] as
applied to IT traffic in the DetNet. DetNet also incorporates the applied to IT traffic in the DetNet. DetNet also incorporates the
use of the 6-bit value of the DCSP field of the Type of Service use of the 6-bit value of the Differentiated Services Code Point
(IPv4) and Traffic Class (IPv6) bytes for flow identification. (DSCP) field of the Type of Service (IPv4) and Traffic Class (IPv6)
However, the DetNet interpretation of the DSCP value for OT traffic bytes for flow identification. However, the DetNet interpretation of
is not equivalent to the PHB selection behavior as defined by the DSCP value for OT traffic is not equivalent to the per-hop
DiffServ. behavior (PHB) selection behavior as defined by Diffserv.
Thus security consideration for DetNet have some aspects in common Thus, security considerations for DetNet have some aspects in common
with DiffServ, in fact overlapping 100% with respect to IP IT with Diffserv, in fact overlapping 100% with respect to IP IT
traffic. Security considerations for these aspects are part of the traffic. Security considerations for these aspects are part of the
existing literature on IP network security, specifically the Security existing literature on IP network security, specifically the Security
Considerations sections of [RFC2474] and [RFC2475]. However, DetNet Considerations sections of [RFC2474] and [RFC2475]. However, DetNet
also introduces timing and other considerations which are not present also introduces timing and other considerations that are not present
in DiffServ, so the DiffServ security considerations are a subset of in Diffserv, so the Diffserv security considerations are a subset of
the DetNet security considerations. the DetNet security considerations.
In the case of DetNet OT traffic, the DSCP value is interpreted In the case of DetNet OT traffic, the DSCP value is interpreted
differently than in DiffServ and contribute to determination of the differently than in Diffserv and contributes to determination of the
service provided to the packet. In DetNet, there are similar service provided to the packet. In DetNet, there are similar
consequences to DiffServ for lack of detection of, or incorrect consequences to Diffserv for lack of detection of, or incorrect
handling of, packets with mismarked DSCP values, and many of the handling of, packets with mismarked DSCP values, and many of the
points made in the DiffServ Security discussions ([RFC2475] Sec. 6.1 points made in the Diffserv Security discussions (Section 6.1 of
, [RFC2474] Sec. 7 and [RFC6274] Sec 3.3.2.1) are also relevant to [RFC2475], Section 7 of [RFC2474], and Section 3.3.2.1 of [RFC6274])
DetNet OT traffic, though perhaps in modified form. For example, in are also relevant to DetNet OT traffic though perhaps in modified
DetNet the effect of an undetected or incorrectly handled maliciously form. For example, in DetNet, the effect of an undetected or
mismarked DSCP field in an OT packet is not identical to affecting incorrectly handled maliciously mismarked DSCP field in an OT packet
the PHB of that packet, since DetNet does not use the PHB concept for is not identical to affecting the PHB of that packet, since DetNet
OT traffic; but nonetheless the service provided to the packet could does not use the PHB concept for OT traffic. Nonetheless, the
be affected, so mitigation measures analogous to those prescribed by service provided to the packet could be affected, so mitigation
DiffServ would be appropriate for DetNet. For example, mismarked measures analogous to those prescribed by Diffserv would be
DSCP values should not cause failure of network nodes. The remarks appropriate for DetNet. For example, mismarked DSCP values should
in [RFC2474] regarding IPsec and Tunnelling Interactions are also not cause failure of network nodes. The remarks in [RFC2474]
relevant (though this is not to say that other sections are less regarding IPsec and Tunneling Interactions are also relevant (though
relevant). this is not to say that other sections are less relevant).
In this discussion, interpretation (and any possible intentional re- In this discussion, interpretation (and any possible intentional re-
marking) of the DSCP values of packets destined for DetNet OT flows marking) of the DSCP values of packets destined for DetNet OT flows
is expected to occur at the ingress to the DetNet domain; once inside is expected to occur at the ingress to the DetNet domain; once inside
the domain, maintaining the integrity of the DSCP values is subject the domain, maintaining the integrity of the DSCP values is subject
to the same handling considerations as any other field in the packet. to the same handling considerations as any other field in the packet.
5. Security Threats 5. Security Threats
This section presents a taxonomy of threats, and analyzes the This section presents a taxonomy of threats and analyzes the possible
possible threats in a DetNet-enabled network. The threats considered threats in a DetNet-enabled network. The threats considered in this
in this section are independent of any specific technologies used to section are independent of any specific technologies used to
implement the DetNet; Section 10 considers attacks that are implement the DetNet; Section 10 considers attacks that are
associated with the DetNet technologies encompassed by [RFC8938]. associated with the DetNet technologies encompassed by [RFC8938].
We distinguish controller plane threats from data plane threats. The We distinguish controller plane threats from data plane threats. The
attack surface may be the same, but the types of attacks as well as attack surface may be the same, but the types of attacks, as well as
the motivation behind them, are different. For example, a delay the motivation behind them, are different. For example, a Delay
attack is more relevant to data plane than to controller plane. attack is more relevant to the data plane than to the controller
There is also a difference in terms of security solutions: the way plane. There is also a difference in terms of security solutions;
you secure the data plane is often different than the way you secure the way you secure the data plane is often different than the way you
the controller plane. secure the controller plane.
5.1. Threat Taxonomy 5.1. Threat Taxonomy
This document employs organizational elements of the threat models of This document employs organizational elements of the threat models of
[RFC7384] and [RFC7835]. This model classifies attackers based on [RFC7384] and [RFC7835]. This model classifies attackers based on
two criteria: two criteria:
o Internal vs. external: internal attackers either have access to a Internal vs. external:
trusted segment of the network or possess the encryption or Internal attackers either have access to a trusted segment of the
authentication keys. External attackers, on the other hand, do network or possess the encryption or authentication keys.
not have the keys and have access only to the encrypted or External attackers, on the other hand, do not have the keys and
authenticated traffic. have access only to the encrypted or authenticated traffic.
o On-path vs. off-path: on-path attackers are located in a position On-path vs. off-path:
that allows interception, modification, or dropping of in-flight On-path attackers are located in a position that allows
protocol packets, whereas off-path attackers can only attack by interception, modification, or dropping of in-flight protocol
generating protocol packets. packets, whereas off-path attackers can only attack by generating
protocol packets.
Regarding the boundary between internal vs. external attackers as Regarding the boundary between internal vs. external attackers as
defined above, please note that in this document we do not make defined above, note that in this document we do not make concrete
concrete recommendations regarding which specific segments of the recommendations regarding which specific segments of the network are
network are to be protected in any specific way, for example via to be protected in any specific way, for example, via encryption or
encryption or authentication. As a result, the boundary as defined authentication. As a result, the boundary as defined above is not
above is not unequivocally specified here. Given that constraint, unequivocally specified here. Given that constraint, the reader can
the reader can view an internal attacker as one who can operate view an internal attacker as one who can operate within the perimeter
within the perimeter defined by the DetNet Edge Nodes (as defined in defined by the DetNet Edge Nodes (as defined in the DetNet
the DetNet Architecture [RFC8655]), allowing that the specifics of Architecture [RFC8655]), allowing that the specifics of what is
what is encrypted or authenticated within this perimeter will vary encrypted or authenticated within this perimeter will vary depending
depending on the implementation. on the implementation.
Care has also been taken to adhere to Section 5 of [RFC3552], both Care has also been taken to adhere to Section 5 of [RFC3552], both
with respect to which attacks are considered out-of-scope for this with respect to which attacks are considered out of scope for this
document, but also which are considered to be the most common threats document, and also which are considered to be the most common threats
(explored further in Section 5.2, Threat Analysis). Most of the (explored further in Section 5.2). Most of the direct threats to
direct threats to DetNet are active attacks (i.e. attacks that modify DetNet are active attacks (i.e., attacks that modify DetNet traffic),
DetNet traffic), but it is highly suggested that DetNet application but it is highly suggested that DetNet application developers take
developers take appropriate measures to protect the content of the appropriate measures to protect the content of the DetNet flows from
DetNet flows from passive attacks (i.e. attacks that observe but do passive attacks (i.e., attacks that observe but do not modify DetNet
not modify DetNet traffic) for example through the use of TLS or traffic), for example, through the use of TLS or DTLS.
DTLS.
DetNet-Service, one of the service scenarios described in DetNet-Service, one of the service scenarios described in
[I-D.varga-detnet-service-model], is the case where a service [DETNET-SERVICE-MODEL], is the case where a service connects DetNet
connects DetNet islands, i.e. two or more otherwise independent islands, i.e., two or more otherwise independent DetNets are
DetNets are connected via a link that is not intrinsically part of connected via a link that is not intrinsically part of either
either network. This implies that there could be DetNet traffic network. This implies that there could be DetNet traffic flowing
flowing over a non-DetNet link, which may provide an attacker with an over a non-DetNet link, which may provide an attacker with an
advantageous opportunity to tamper with DetNet traffic. The security advantageous opportunity to tamper with DetNet traffic. The security
properties of non-DetNet links are outside of the scope of DetNet properties of non-DetNet links are outside of the scope of DetNet
Security, but it should be noted that use of non-DetNet services to Security, but it should be noted that use of non-DetNet services to
interconnect DetNets merits security analysis to ensure the integrity interconnect DetNets merits security analysis to ensure the integrity
of the networks involved. of the networks involved.
5.2. Threat Analysis 5.2. Threat Analysis
5.2.1. Delay 5.2.1. Delay
skipping to change at page 16, line 31 skipping to change at line 743
misclassify the flow. Alternatively, the attacker can inject traffic misclassify the flow. Alternatively, the attacker can inject traffic
that is tailored to appear as if it belongs to a legitimate DetNet that is tailored to appear as if it belongs to a legitimate DetNet
flow. The potential consequence is that the DetNet flow resource flow. The potential consequence is that the DetNet flow resource
allocation cannot guarantee the performance that is expected when the allocation cannot guarantee the performance that is expected when the
flow identification works correctly. flow identification works correctly.
5.2.3. Resource Segmentation (Inter-segment Attack) Vulnerability 5.2.3. Resource Segmentation (Inter-segment Attack) Vulnerability
DetNet components are expected to split their resources between DetNet components are expected to split their resources between
DetNet flows in a way that prevents traffic from one DetNet flow from DetNet flows in a way that prevents traffic from one DetNet flow from
affecting the performance of other DetNet flows, and also prevents affecting the performance of other DetNet flows and also prevents
non-DetNet traffic from affecting DetNet flows. However, perhaps due non-DetNet traffic from affecting DetNet flows. However, perhaps due
to implementation constraints, some resources may be partially to implementation constraints, some resources may be partially
shared, and an attacker may try to exploit this property. For shared, and an attacker may try to exploit this property. For
example, an attacker can inject traffic in order to exhaust network example, an attacker can inject traffic in order to exhaust network
resources such that DetNet packets which share resources with the resources such that DetNet packets that share resources with the
injected traffic may be dropped or delayed. Such injected traffic injected traffic may be dropped or delayed. Such injected traffic
may be part of DetNet flows or non-DetNet traffic. may be part of DetNet flows or non-DetNet traffic.
Another example of a resource segmentation attack is the case in Another example of a Resource Segmentation attack is the case in
which an attacker is able to overload the exception path queue on the which an attacker is able to overload the exception path queue on the
router, i.e. a "slow path" typically taken by control or OAM packets router, i.e., a "slow path" typically taken by control or OAM packets
which are diverted from the data plane because they require that are diverted from the data plane because they require processing
processing by a CPU. DetNet OT flows are typically configured to by a CPU. DetNet OT flows are typically configured to take the "fast
take the "fast path" through the data plane, to minimize latency. path" through the data plane to minimize latency. However, if there
However if there is only one queue from the forwarding ASIC to the is only one queue from the forwarding Application-Specific Integrated
exception path, and for some reason the system is configured such Circuit (ASIC) to the exception path, and for some reason the system
that any DetNet packets must be handled on this exception path, then is configured such that any DetNet packets must be handled on this
saturating the exception path could result in delaying or dropping of exception path, then saturating the exception path could result in
DetNet packets. the delaying or dropping of DetNet packets.
5.2.4. Packet Replication and Elimination 5.2.4. Packet Replication and Elimination
5.2.4.1. Replication: Increased Attack Surface 5.2.4.1. Replication: Increased Attack Surface
Redundancy is intended to increase the robustness and survivability Redundancy is intended to increase the robustness and survivability
of DetNet flows, and replication over multiple paths can potentially of DetNet flows, and replication over multiple paths can potentially
mitigate an attack that is limited to a single path. However, the mitigate an attack that is limited to a single path. However, the
fact that packets are replicated over multiple paths increases the fact that packets are replicated over multiple paths increases the
attack surface of the network, i.e., there are more points in the attack surface of the network, i.e., there are more points in the
network that may be subject to attacks. network that may be subject to attacks.
5.2.4.2. Replication-related Header Manipulation 5.2.4.2. Replication-Related Header Manipulation
An attacker can manipulate the replication-related header fields. An attacker can manipulate the replication-related header fields.
This capability opens the door for various types of attacks. For This capability opens the door for various types of attacks. For
example: example:
o Forward both replicas - malicious change of a packet SN (Sequence Forward both replicas:
Number) can cause both replicas of the packet to be forwarded. Malicious change of a packet SN (Sequence Number) can cause both
Note that this attack has a similar outcome to a replay attack. replicas of the packet to be forwarded. Note that this attack has
a similar outcome to a replay attack.
o Eliminate both replicas - SN manipulation can be used to cause Eliminate both replicas:
both replicas to be eliminated. In this case an attacker that has SN manipulation can be used to cause both replicas to be
access to a single path can cause packets from other paths to be eliminated. In this case, an attacker that has access to a single
dropped, thus compromising some of the advantage of path path can cause packets from other paths to be dropped, thus
redundancy. compromising some of the advantage of path redundancy.
o Flow hijacking - an attacker can hijack a DetNet flow with access Flow hijacking:
to a single path by systematically replacing the SNs on the given An attacker can hijack a DetNet flow with access to a single path
path with higher SN values. For example, an attacker can replace by systematically replacing the SNs on the given path with higher
every SN value S with a higher value S+C, where C is a constant SN values. For example, an attacker can replace every SN value S
integer. Thus, the attacker creates a false illusion that the with a higher value S+C, where C is a constant integer. Thus, the
attacked path has the lowest delay, causing all packets from other attacker creates a false illusion that the attacked path has the
paths to be eliminated in favor of the attacked path. Once the lowest delay, causing all packets from other paths to be
flow from the compromised path is favored by the eliminating eliminated in favor of the attacked path. Once the flow from the
bridge, the flow has effectively been hijacked by the attacker. compromised path is favored by the eliminating bridge, the flow
It is now possible for the attacker to either replace en route has effectively been hijacked by the attacker. It is now possible
packets with malicious packets, or to simply inject errors into for the attacker to either replace en route packets with malicious
the packets, causing the packets to be dropped at their packets, or to simply inject errors into the packets, causing the
destination. packets to be dropped at their destination.
o Amplification - an attacker who injects packets into a flow that Amplification:
is to be replicated will have their attack amplified through the An attacker who injects packets into a flow that is to be
replicated will have their attack amplified through the
replication process. This is no different than any attacker who replication process. This is no different than any attacker who
injects packets that are delivered through multicast, broadcast, injects packets that are delivered through multicast, broadcast,
or other point-to-multi-point mechanisms. or other point-to-multi-point mechanisms.
5.2.5. Controller Plane 5.2.5. Controller Plane
5.2.5.1. Path Choice Manipulation 5.2.5.1. Path Choice Manipulation
5.2.5.1.1. Control or Signaling Packet Modification 5.2.5.1.1. Control or Signaling Packet Modification
An attacker can maliciously modify en route control packets in order An attacker can maliciously modify en route control packets in order
to disrupt or manipulate the DetNet path/resource allocation. to disrupt or manipulate the DetNet path/resource allocation.
5.2.5.1.2. Control or Signaling Packet Injection 5.2.5.1.2. Control or Signaling Packet Injection
An attacker can maliciously inject control packets in order to An attacker can maliciously inject control packets in order to
disrupt or manipulate the DetNet path/resource allocation. disrupt or manipulate the DetNet path/resource allocation.
5.2.5.1.3. Increased Attack Surface 5.2.5.1.3. Increased Attack Surface
One of the possible consequences of a path manipulation attack is an One of the possible consequences of a Path Manipulation attack is an
increased attack surface. Thus, when the attack described in the increased attack surface. Thus, when the attack described in the
previous subsection is implemented, it may increase the potential of previous subsection is implemented, it may increase the potential of
other attacks to be performed. other attacks to be performed.
5.2.5.2. Compromised Controller 5.2.5.2. Compromised Controller
An attacker can subvert a legitimate controller (or subvert another An attacker can subvert a legitimate controller (or subvert another
component such that it represents itself as a legitimate controller) component such that it represents itself as a legitimate controller)
with the result that the network nodes incorrectly believe it is with the result that the network nodes incorrectly believe it is
authorized to instruct them. authorized to instruct them.
The presence of a compromised node or controller in a DetNet is not a The presence of a compromised node or controller in a DetNet is not a
threat that arises as a result of determinism or time sensitivity; threat that arises as a result of determinism or time sensitivity;
the same techniques used to prevent or mitigate against compromised the same techniques used to prevent or mitigate against compromised
nodes in any network are equally applicable in the DetNet case. The nodes in any network are equally applicable in the DetNet case. The
act of compromising a controller may not even be within the act of compromising a controller may not even be within the
capabilities of our defined attacker types - in other words it may capabilities of our defined attacker types -- in other words, it may
not be achievable via packet traffic at all, whether internal or not be achievable via packet traffic at all, whether internal or
external, on-path or off-path. It might be accomplished for example external, on path or off path. It might be accomplished, for
by a human with physical access to the component, who could upload example, by a human with physical access to the component, who could
bogus firmware to it via a USB stick. All of this underscores the upload bogus firmware to it via a USB stick. All of this underscores
requirement for careful overall system security design in a DetNet, the requirement for careful overall system security design in a
given that the effects of even one bad actor on the network can be DetNet, given that the effects of even one bad actor on the network
potentially catastrophic. can be potentially catastrophic.
Security concerns specific to any given controller plane technology Security concerns specific to any given controller plane technology
used in DetNet will be addressed by the DetNet documents associated used in DetNet will be addressed by the DetNet documents associated
with that technology. with that technology.
5.2.6. Reconnaissance 5.2.6. Reconnaissance
A passive eavesdropper can identify DetNet flows and then gather A passive eavesdropper can identify DetNet flows and then gather
information about en route DetNet flows, e.g., the number of DetNet information about en route DetNet flows, e.g., the number of DetNet
flows, their bandwidths, their schedules, or other temporal or flows, their bandwidths, their schedules, or other temporal or
statistical properties. The gathered information can later be used statistical properties. The gathered information can later be used
to invoke other attacks on some or all of the flows. to invoke other attacks on some or all of the flows.
DetNet flows are typically uniquely identified by their 6-tuple, i.e. DetNet flows are typically uniquely identified by their 6-tuple,
fields within the L3 or L4 header, however in some implementations i.e., fields within the L3 or L4 header. However, in some
the flow ID may also be augmented by additional per-flow attributes implementations, the flow ID may also be augmented by additional per-
known to the system, e.g. above L4. For the purpose of this document flow attributes known to the system, e.g., above L4. For the purpose
we assume any such additional fields used for flow ID are encrypted of this document, we assume any such additional fields used for flow
and/or integrity-protected from external attackers. Note however ID are encrypted and/or integrity protected from external attackers.
that existing OT protocols designed for use on dedicated secure Note however that existing OT protocols designed for use on dedicated
networks may not intrinsically provide such protection, in which case secure networks may not intrinsically provide such protection, in
IPsec or transport layer security mechanisms may be needed. which case IPsec or transport-layer security mechanisms may be
needed.
5.2.7. Time Synchronization Mechanisms 5.2.7. Time-Synchronization Mechanisms
An attacker can use any of the attacks described in [RFC7384] to An attacker can use any of the attacks described in [RFC7384] to
attack the synchronization protocol, thus affecting the DetNet attack the synchronization protocol, thus affecting the DetNet
service. service.
5.3. Threat Summary 5.3. Threat Summary
A summary of the attacks that were discussed in this section is A summary of the attacks that were discussed in this section is
presented in Figure 1. For each attack, the table specifies the type presented in Table 1. For each attack, the table specifies the type
of attackers that may invoke the attack. In the context of this of attackers that may invoke the attack. In the context of this
summary, the distinction between internal and external attacks is summary, the distinction between internal and external attacks is
under the assumption that a corresponding security mechanism is being under the assumption that a corresponding security mechanism is being
used, and that the corresponding network equipment takes part in this used, and that the corresponding network equipment takes part in this
mechanism. mechanism.
+-------------------------------------------+----+-----+----+-----+ +======================+=========================================+
| Attack | Attacker Type | | Attack | Attacker Type |
| +----------+----------+ | +====================+====================+
| | Internal | External | | | Internal | External |
| |On-P|Off-P|On-P|Off-P| | +=========+==========+=========+==========+
+-------------------------------------------+----+-----+----+-----+ | | On-Path | Off-Path | On-Path | Off-Path |
|Delay attack | + | | + | | +======================+=========+==========+=========+==========+
+-------------------------------------------+----+-----+----+-----+ | Delay Attack | + | | + | |
|DetNet Flow Modification or Spoofing | + | + | | | +----------------------+---------+----------+---------+----------+
+-------------------------------------------+----+-----+----+-----+ | DetNet Flow | + | + | | |
|Inter-segment Attack | + | + | + | + | | Modification or | | | | |
+-------------------------------------------+----+-----+----+-----+ | Spoofing | | | | |
|Replication: Increased Attack Surface | + | + | + | + | +----------------------+---------+----------+---------+----------+
+-------------------------------------------+----+-----+----+-----+ | Inter-segment Attack | + | + | + | + |
|Replication-related Header Manipulation | + | | | | +----------------------+---------+----------+---------+----------+
+-------------------------------------------+----+-----+----+-----+ | Replication: | + | + | + | + |
|Path Manipulation | + | + | | | | Increased Attack | | | | |
+-------------------------------------------+----+-----+----+-----+ | Surface | | | | |
|Path Choice: Increased Attack Surface | + | + | + | + | +----------------------+---------+----------+---------+----------+
+-------------------------------------------+----+-----+----+-----+ | Replication-Related | + | | | |
|Control or Signaling Packet Modification | + | | | | | Header Manipulation | | | | |
+-------------------------------------------+----+-----+----+-----+ +----------------------+---------+----------+---------+----------+
|Control or Signaling Packet Injection | + | + | | | | Path Manipulation | + | + | | |
+-------------------------------------------+----+-----+----+-----+ +----------------------+---------+----------+---------+----------+
|Reconnaissance | + | | + | | | Path Choice: | + | + | + | + |
+-------------------------------------------+----+-----+----+-----+ | Increased Attack | | | | |
|Attacks on Time Synchronization Mechanisms | + | + | + | + | | Surface | | | | |
+-------------------------------------------+----+-----+----+-----+ +----------------------+---------+----------+---------+----------+
| Control or Signaling | + | | | |
| Packet Modification | | | | |
+----------------------+---------+----------+---------+----------+
| Control or Signaling | + | + | | |
| Packet Injection | | | | |
+----------------------+---------+----------+---------+----------+
| Reconnaissance | + | | + | |
+----------------------+---------+----------+---------+----------+
| Attacks on Time- | + | + | + | + |
| Synchronization | | | | |
| Mechanisms | | | | |
+----------------------+---------+----------+---------+----------+
Figure 1: Threat Analysis Summary Table 1: Threat Analysis Summary
6. Security Threat Impacts 6. Security Threat Impacts
When designing security for a DetNet, as with any network, it may be When designing security for a DetNet, as with any network, it may be
prohibitively expensive or technically infeasible to thoroughly prohibitively expensive or technically infeasible to thoroughly
protect against every possible threat. Thus the security designer protect against every possible threat. Thus, the security designer
must be informed (for example by an application domain expert such as must be informed (for example, by an application domain expert such
a product manager) regarding the relative significance of the various as a product manager) regarding the relative significance of the
threats and their impact if a successful attack is carried out. In various threats and their impact if a successful attack is carried
this section we present an example of a possible template for such a out. In this section, we present an example of a possible template
communication, culminating in a table (Figure 2) which lists a set of for such a communication, culminating in a table (Table 2) that lists
threats under consideration, and some values characterizing their a set of threats under consideration, and some values characterizing
relative impact in the context of a given industry. The specific their relative impact in the context of a given industry. The
threats, industries, and impact values in the table are provided only specific threats, industries, and impact values in the table are
as an example of this kind of assessment and its communication; they provided only as an example of this kind of assessment and its
are not intended to be taken literally. communication; they are not intended to be taken literally.
This section considers assessment of the relative impacts of the This section considers assessment of the relative impacts of the
attacks described in Section 5, Security Threats. In this section, attacks described in Section 5. In this section, the impacts as
the impacts as described assume that the associated mitigation is not described assume that the associated mitigation is not present or has
present or has failed. Mitigations are discussed in Section 7, failed. Mitigations are discussed in Section 7.
Security Threat Mitigation.
In computer security, the impact (or consequence) of an incident can In computer security, the impact (or consequence) of an incident can
be measured in loss of confidentiality, integrity or availability of be measured in loss of confidentiality, integrity, or availability of
information. In the case of time sensitive or OT networks (though information. In the case of OT or time sensitive networks (though
not to the exclusion of IT or non-time-sensitive networks) the impact not to the exclusion of IT or non-time-sensitive networks), the
of an exploit can also include failure or malfunction of mechanical impact of an exploit can also include failure or malfunction of
and/or other physical systems. mechanical and/or other physical systems.
DetNet raises these stakes significantly for OT applications, DetNet raises these stakes significantly for OT applications,
particularly those which may have been designed to run in an OT-only particularly those that may have been designed to run in an OT-only
environment and thus may not have been designed for security in an IT environment and thus may not have been designed for security in an IT
environment with its associated components, services and protocols. environment with its associated components, services, and protocols.
The extent of impact of a successful vulnerability exploit varies The extent of impact of a successful vulnerability exploit varies
considerably by use case and by industry; additional insights considerably by use case and by industry; additional insight
regarding the individual use cases is available from [RFC8578], regarding the individual use cases is available from "Deterministic
DetNet Use Cases. Each of those use cases is represented in Networking Use Cases" [RFC8578]. Each of those use cases is
Figure 2, including Pro Audio, Electrical Utilities, Industrial M2M represented in Table 2, including Pro Audio, Electrical Utilities,
(split into two areas, M2M Data Gathering and M2M Control Loop), and Industrial M2M (split into two areas: M2M Data Gathering and M2M
others. Control Loop), and others.
Aspects of Impact (left column) include Criticality of Failure, Aspects of Impact (left column) include Criticality of Failure,
Effects of Failure, Recovery, and DetNet Functional Dependence. Effects of Failure, Recovery, and DetNet Functional Dependence.
Criticality of failure summarizes the seriousness of the impact. The Criticality of failure summarizes the seriousness of the impact. The
impact of a resulting failure can affect many different metrics that impact of a resulting failure can affect many different metrics that
vary greatly in scope and severity. In order to reduce the number of vary greatly in scope and severity. In order to reduce the number of
variables, only the following were included: Financial, Health and variables, only the following were included: Financial, Health and
Safety, Effect on a Single Organization, and Effect on Multiple Safety, Effect on a Single Organization, and Effect on Multiple
Organizations. Recovery outlines how long it would take for an Organizations. Recovery outlines how long it would take for an
affected use case to get back to its pre-failure state (Recovery time affected use case to get back to its pre-failure state (Recovery Time
objective, RTO), and how much of the original service would be lost Objective, RTO) and how much of the original service would be lost in
in between the time of service failure and recovery to original state between the time of service failure and recovery to original state
(Recovery Point Objective, RPO). DetNet dependence maps how much the (Recovery Point Objective, RPO). DetNet dependence maps how much the
following DetNet service objectives contribute to impact of failure: following DetNet service objectives contribute to impact of failure:
Time dependency, data integrity, source node integrity, availability, time dependency, data integrity, source node integrity, availability,
latency/jitter. and latency/jitter.
The scale of the Impact mappings is low, medium, and high. In some The scale of the Impact mappings is low, medium, and high. In some
use cases there may be a multitude of specific applications in which use cases, there may be a multitude of specific applications in which
DetNet is used. For simplicity this section attempts to average the DetNet is used. For simplicity, this section attempts to average the
varied impacts of different applications. This section does not varied impacts of different applications. This section does not
address the overall risk of a certain impact which would require the address the overall risk of a certain impact that would require the
likelihood of a failure happening. likelihood of a failure happening.
In practice any such ratings will vary from case to case; the ratings In practice, any such ratings will vary from case to case; the
shown here are given as examples. ratings shown here are given as examples.
Table +==============+=====+======+======+==========+======+======+======+
+------------------+-----------------------------------------+-----+ | | PRO | Util | Bldg | Wireless | Cell | M2M | M2M |
| | Pro A | Util | Bldg |Wire- | Cell |M2M |M2M | | | A | | | | | Data | Ctrl |
| | | | | less | |Data |Ctrl | +==============+=====+======+======+==========+======+======+======+
+------------------+-----------------------------------------+-----+ | Criticality | Med | Hi | Low | Med | Med | Med | Med |
| Criticality | Med | Hi | Low | Med | Med | Med | Med | +==============+=====+======+======+==========+======+======+======+
+------------------+-----------------------------------------+-----+ | Effects |
| Effects +==============+=====+======+======+==========+======+======+======+
+------------------+-----------------------------------------+-----+ | Financial | Med | Hi | Med | Med | Low | Med | Med |
| Financial | Med | Hi | Med | Med | Low | Med | Med | +--------------+-----+------+------+----------+------+------+------+
+------------------+-----------------------------------------+-----+ | Health/ | Med | Hi | Hi | Med | Med | Med | Med |
| Health/Safety | Med | Hi | Hi | Med | Med | Med | Med | | Safety | | | | | | | |
+------------------+-----------------------------------------+-----+ +--------------+-----+------+------+----------+------+------+------+
| Affects 1 org | Hi | Hi | Med | Hi | Med | Med | Med | | Affects 1 | Hi | Hi | Med | Hi | Med | Med | Med |
+------------------+-----------------------------------------+-----+ | org | | | | | | | |
| Affects >1 org | Med | Hi | Low | Med | Med | Med | Med | +--------------+-----+------+------+----------+------+------+------+
+------------------+-----------------------------------------+-----+ | Affects >1 | Med | Hi | Low | Med | Med | Med | Med |
|Recovery | org | | | | | | | |
+------------------+-----------------------------------------+-----+ +==============+=====+======+======+==========+======+======+======+
| Recov Time Obj | Med | Hi | Med | Hi | Hi | Hi | Hi | | Recovery |
+------------------+-----------------------------------------+-----+ +==============+=====+======+======+==========+======+======+======+
| Recov Point Obj | Med | Hi | Low | Med | Low | Hi | Hi | | Recov Time | Med | Hi | Med | Hi | Hi | Hi | Hi |
+------------------+-----------------------------------------+-----+ | Obj | | | | | | | |
|DetNet Dependence +--------------+-----+------+------+----------+------+------+------+
+------------------+-----------------------------------------+-----+ | Recov Point | Med | Hi | Low | Med | Low | Hi | Hi |
| Time Dependency | Hi | Hi | Low | Hi | Med | Low | Hi | | Obj | | | | | | | |
+------------------+-----------------------------------------+-----+ +==============+=====+======+======+==========+======+======+======+
| Latency/Jitter | Hi | Hi | Med | Med | Low | Low | Hi | | DetNet Dependence |
+------------------+-----------------------------------------+-----+ +==============+=====+======+======+==========+======+======+======+
| Data Integrity | Hi | Hi | Med | Hi | Low | Hi | Hi | | Time | Hi | Hi | Low | Hi | Med | Low | Hi |
+------------------+-----------------------------------------+-----+ | Dependence | | | | | | | |
| Src Node Integ | Hi | Hi | Med | Hi | Med | Hi | Hi | +--------------+-----+------+------+----------+------+------+------+
+------------------+-----------------------------------------+-----+ | Latency/ | Hi | Hi | Med | Med | Low | Low | Hi |
| Availability | Hi | Hi | Med | Hi | Low | Hi | Hi | | Jitter | | | | | | | |
+------------------+-----------------------------------------+-----+ +--------------+-----+------+------+----------+------+------+------+
| Data | Hi | Hi | Med | Hi | Low | Hi | Hi |
| Integrity | | | | | | | |
+--------------+-----+------+------+----------+------+------+------+
| Src Node | Hi | Hi | Med | Hi | Med | Hi | Hi |
| Integ | | | | | | | |
+--------------+-----+------+------+----------+------+------+------+
| Availability | Hi | Hi | Med | Hi | Low | Hi | Hi |
+--------------+-----+------+------+----------+------+------+------+
Figure 2: Impact of Attacks by Use Case Industry Table 2: Impact of Attacks by Use Case Industry
The rest of this section will cover impact of the different groups in The rest of this section will cover impact of the different groups in
more detail. more detail.
6.1. Delay-Attacks 6.1. Delay Attacks
6.1.1. Data Plane Delay Attacks 6.1.1. Data Plane Delay Attacks
Note that 'delay attack' also includes the possibility of a 'negative Note that "Delay attack" also includes the possibility of a "negative
delay' or early arrival of a packet, or possibly adversely changing delay" or early arrival of a packet, or possibly adversely changing
the timestamp value. the timestamp value.
Delayed messages in a DetNet link can result in the same behavior as Delayed messages in a DetNet link can result in the same behavior as
dropped messages in ordinary networks, since the services attached to dropped messages in ordinary networks, since the services attached to
the DetNet flow are likely to have strict delivery time requirements. the DetNet flow are likely to have strict delivery time requirements.
For a single path scenario, disruption within the single flow is a For a single-path scenario, disruption within the single flow is a
real possibility. In a multipath scenario, large delays or real possibility. In a multipath scenario, large delays or
instabilities in one DetNet flow can also lead to increased buffer instabilities in one DetNet flow can also lead to increased buffer
and processor resource consumption at the eliminating router. and processor resource consumption at the eliminating router.
A data-plane delay attack on a system controlling substantial moving A data plane Delay attack on a system controlling substantial moving
devices, for example in industrial automation, can cause physical devices, for example, in industrial automation, can cause physical
damage. For example, if the network promises a bounded latency of damage. For example, if the network promises a bounded latency of 2
2ms for a flow, yet the machine receives it with 5ms latency, the ms for a flow, yet the machine receives it with 5 ms latency, the
control loop of the machine may become unstable. control loop of the machine may become unstable.
6.1.2. Controller Plane Delay Attacks 6.1.2. Controller Plane Delay Attacks
In and of itself, this is not directly a threat to the DetNet In and of itself, this is not directly a threat to the DetNet
service, but the effects of delaying control messages can have quite service, but the effects of delaying control messages can have quite
adverse effects later. adverse effects later.
o Delayed tear-down can lead to resource leakage, which in turn can * Delayed teardown can lead to resource leakage, which in turn can
result in failure to allocate new DetNet flows, finally giving result in failure to allocate new DetNet flows, finally giving
rise to a denial of service attack. rise to a denial-of-service attack.
o Failure to deliver, or severely delaying, controller plane * Failure to deliver, or severely delaying, controller plane
messages adding an endpoint to a multicast-group will prevent the messages adding an endpoint to a multicast group will prevent the
new endpoint from receiving expected frames thus disrupting new endpoint from receiving expected frames thus disrupting
expected behavior. expected behavior.
o Delaying messages removing an endpoint from a group can lead to * Delaying messages that remove an endpoint from a group can lead to
loss of privacy as the endpoint will continue to receive messages loss of privacy, as the endpoint will continue to receive messages
even after it is supposedly removed. even after it is supposedly removed.
6.2. Flow Modification and Spoofing 6.2. Flow Modification and Spoofing
6.2.1. Flow Modification 6.2.1. Flow Modification
If the contents of a packet header or body can be modified by the If the contents of a packet header or body can be modified by the
attacker, this can cause the packet to be routed incorrectly or attacker, this can cause the packet to be routed incorrectly or
dropped, or the payload to be corrupted or subtly modified. Thus, dropped, or the payload to be corrupted or subtly modified. Thus,
the potential impact of a modification attack includes disrupting the the potential impact of a Modification attack includes disrupting the
application as well as the network equipment. application as well as the network equipment.
6.2.2. Spoofing 6.2.2. Spoofing
6.2.2.1. Dataplane Spoofing 6.2.2.1. Data Plane Spoofing
Spoofing dataplane messages can result in increased resource Spoofing data plane messages can result in increased resource
consumptions on the routers throughout the network as it will consumption on the routers throughout the network as it will increase
increase buffer usage and processor utilization. This can lead to buffer usage and processor utilization. This can lead to resource
resource exhaustion and/or increased delay. exhaustion and/or increased delay.
If the attacker manages to create valid headers, the false messages If the attacker manages to create valid headers, the false messages
can be forwarded through the network, using part of the allocated can be forwarded through the network, using part of the allocated
bandwidth. This in turn can cause legitimate messages to be dropped bandwidth. This in turn can cause legitimate messages to be dropped
when the resource budget has been exhausted. when the resource budget has been exhausted.
Finally, the endpoint will have to deal with invalid messages being Finally, the endpoint will have to deal with invalid messages being
delivered to the endpoint instead of (or in addition to) a valid delivered to the endpoint instead of (or in addition to) a valid
message. message.
6.2.2.2. Controller Plane Spoofing 6.2.2.2. Controller Plane Spoofing
A successful controller plane spoofing-attack will potentially have A successful Controller Plane Spoofing attack will potentially have
adverse effects. It can do virtually anything from: adverse effects. It can do virtually anything from:
o modifying existing DetNet flows by changing the available * modifying existing DetNet flows by changing the available
bandwidth bandwidth
o add or remove endpoints from a DetNet flow * adding or removing endpoints from a DetNet flow
o drop DetNet flows completely * dropping DetNet flows completely
o falsely create new DetNet flows (exhaust the systems resources, or * falsely creating new DetNet flows (exhausting the systems
to enable DetNet flows that are outside the control of the Network resources or enabling DetNet flows that are outside the control of
Engineer) the network engineer)
6.3. Segmentation Attacks (Injection)
6.3. Segmentation Attacks (injection)
6.3.1. Data Plane Segmentation 6.3.1. Data Plane Segmentation
Injection of false messages in a DetNet flow could lead to exhaustion Injection of false messages in a DetNet flow could lead to exhaustion
of the available bandwidth for that flow if the routers attribute of the available bandwidth for that flow if the routers attribute
these false messages to the resource budget of that flow. these false messages to the resource budget of that flow.
In a multipath scenario, injected messages will cause increased In a multipath scenario, injected messages will cause increased
processor utilization in elimination routers. If enough paths are processor utilization in elimination routers. If enough paths are
subject to malicious injection, the legitimate messages can be subject to malicious injection, the legitimate messages can be
dropped. Likewise it can cause an increase in buffer usage. In dropped. Likewise, it can cause an increase in buffer usage. In
total, it will consume more resources in the routers than normal, total, it will consume more resources in the routers than normal,
giving rise to a resource exhaustion attack on the routers. giving rise to a resource-exhaustion attack on the routers.
If a DetNet flow is interrupted, the end application will be affected If a DetNet flow is interrupted, the end application will be affected
by what is now a non-deterministic flow. Note that there are many by what is now a non-deterministic flow. Note that there are many
possible sources of flow interruptions, for example, but not limited possible sources of flow interruptions, for example, but not limited
to, such physical layer conditions as a broken wire or a radio link to, such physical-layer conditions as a broken wire or a radio link
which is compromised by interference. that is compromised by interference.
6.3.2. Controller Plane Segmentation 6.3.2. Controller Plane Segmentation
In a successful controller plane segmentation attack, control In a successful Controller Plane Segmentation attack, control
messages are acted on by nodes in the network, unbeknownst to the messages are acted on by nodes in the network, unbeknownst to the
central controller or the network engineer. This has the potential central controller or the network engineer. This has the potential
to: to:
o create new DetNet flows (exhausting resources) * create new DetNet flows (exhausting resources)
o drop existing DetNet flows (denial of service) * drop existing DetNet flows (denial of service)
o add end-stations to a multicast group (loss of privacy) * add end stations to a multicast group (loss of privacy)
o remove end-stations from a multicast group (reduction of service) * remove end stations from a multicast group (reduction of service)
o modify the DetNet flow attributes (affecting available bandwidth) * modify the DetNet flow attributes (affecting available bandwidth)
If an attacker can inject control messages without the central If an attacker can inject control messages without the central
controller knowing, then one or more components in the network may controller knowing, then one or more components in the network may
get into a state that is not expected by the controller. At that get into a state that is not expected by the controller. At that
point, if the controller initiates a command, the effect of that point, if the controller initiates a command, the effect of that
command may not be as expected, since the target of the command may command may not be as expected, since the target of the command may
have started from a different initial state. have started from a different initial state.
6.4. Replication and Elimination 6.4. Replication and Elimination
The Replication and Elimination is relevant only to data plane The Replication and Elimination functions are relevant only to data
messages as controller plane messages are not subject to multipath plane messages as controller plane messages are not subject to
routing. multipath routing.
6.4.1. Increased Attack Surface 6.4.1. Increased Attack Surface
The impact of an increased attack surface is that it increases the The impact of an increased attack surface is that it increases the
probability that the network can be exposed to an attacker. This can probability that the network can be exposed to an attacker. This can
facilitate a wide range of specific attacks, and their respective facilitate a wide range of specific attacks, and their respective
impacts are discussed in other subsections of this section. impacts are discussed in other subsections of this section.
6.4.2. Header Manipulation at Elimination Routers 6.4.2. Header Manipulation at Elimination Routers
skipping to change at page 26, line 35 skipping to change at line 1220
If an attacker can inject control packets undetected, the network can If an attacker can inject control packets undetected, the network can
be severely compromised. be severely compromised.
6.7. Reconnaissance 6.7. Reconnaissance
Of all the attacks, this is one of the most difficult to detect and Of all the attacks, this is one of the most difficult to detect and
counter. counter.
An attacker can, at their leisure, observe over time various aspects An attacker can, at their leisure, observe over time various aspects
of the messaging and signalling, learning the intent and purpose of of the messaging and signaling, learning the intent and purpose of
the traffic flows. Then at some later date, possibly at an important the traffic flows. Then at some later date, possibly at an important
time in the operational context, they might launch an attack based on time in the operational context, they might launch an attack based on
that knowledge. that knowledge.
The flow-id in the header of the data plane messages gives an The flow ID in the header of the data plane messages gives an
attacker a very reliable identifier for DetNet traffic, and this attacker a very reliable identifier for DetNet traffic, and this
traffic has a high probability of going to lucrative targets. traffic has a high probability of going to lucrative targets.
Applications which are ported from a private OT network to the higher Applications that are ported from a private OT network to the higher
visibility DetNet environment may need to be adapted to limit visibility DetNet environment may need to be adapted to limit
distinctive flow properties that could make them susceptible to distinctive flow properties that could make them susceptible to
reconnaissance. reconnaissance.
6.8. Attacks on Time Synchronization Mechanisms 6.8. Attacks on Time-Synchronization Mechanisms
DetNet relies on an underlying time synchronization mechanism, and DetNet relies on an underlying time-synchronization mechanism;
therefore a compromised synchronization mechanism may cause DetNet therefore, a compromised synchronization mechanism may cause DetNet
nodes to malfunction. Specifically, DetNet flows may fail to meet nodes to malfunction. Specifically, DetNet flows may fail to meet
their latency requirements and deterministic behavior, thus causing their latency requirements and deterministic behavior, thus causing
DoS to DetNet applications. DoS to DetNet applications.
6.9. Attacks on Path Choice 6.9. Attacks on Path Choice
This is covered in part in Section 6.3, Segmentation Attacks, and as This is covered in part in Section 6.3 (Segmentation Attacks
with Replication and Elimination ( Section 6.4), this is relevant for (Injection)) and, as with Replication and Elimination (see
DataPlane messages. Section 6.4), this is relevant for data plane messages.
7. Security Threat Mitigation 7. Security Threat Mitigation
This section describes a set of measures that can be taken to This section describes a set of measures that can be taken to
mitigate the attacks described in Section 5, Security Threats. These mitigate the attacks described in Section 5. These mitigations
mitigations should be viewed as a set of tools, any of which can be should be viewed as a set of tools, any of which can be used
used individually or in concert. The DetNet component and/or system individually or in concert. The DetNet component and/or system and/
and/or application designer can apply these tools, as necessary based or application designer can apply these tools as necessary based on a
on a system-specific threat analysis. system-specific threat analysis.
Some of the technology-specific security considerations and Some of the technology-specific security considerations and
mitigation approaches are further discussed in the DetNet data plane mitigation approaches are further discussed in DetNet data plane
solution documents, such as [RFC8938], [RFC8939], [RFC8964], solution documents, such as [RFC8938], [RFC8939], [RFC8964],
[I-D.ietf-detnet-mpls-over-udp-ip], and [RFC9025], and [RFC9056].
[I-D.ietf-detnet-ip-over-mpls].
7.1. Path Redundancy 7.1. Path Redundancy
Description Description: Path redundancy is a DetNet flow that can be forwarded
simultaneously over multiple paths. Packet Replication and
A DetNet flow that can be forwarded simultaneously over multiple Elimination [RFC8655] provide resiliency to dropped or delayed
paths. Packet replication and elimination [RFC8655] provides packets. This redundancy improves the robustness to failures and
resiliency to dropped or delayed packets. This redundancy to on-path attacks.
improves the robustness to failures and to on-path attacks. Note:
At the time of this writing, PREOF is not defined for the IP data
plane.
Related attacks | Note: At the time of this writing, PREOF is not defined for
| the IP data plane.
Path redundancy can be used to mitigate various on-path attacks, Related attacks: Path redundancy can be used to mitigate various on-
including attacks described in Section 5.2.1, Section 5.2.2, path attacks, including attacks described in Sections 5.2.1,
Section 5.2.3, and Section 5.2.7. However it is also possible 5.2.2, 5.2.3, and 5.2.7. However, it is also possible that
that multiple paths may make it more difficult to locate the multiple paths may make it more difficult to locate the source of
source of an on-path attacker. an on-path attacker.
A delay modulation attack could result in extensively exercising A Delay Modulation attack could result in extensively exercising
parts of the code that wouldn't normally be extensively exercised otherwise unused code paths to expose hidden flaws. Subtle race
and thus might expose flaws in the system that might otherwise not conditions and memory allocation bugs in error-handling paths are
be exposed. classic examples of this.
7.2. Integrity Protection 7.2. Integrity Protection
Description Description: Integrity protection in the scope of DetNet is the
ability to detect if a packet header has been modified
Integrity Protection in the scope of DetNet is the ability to (maliciously or otherwise) and if so, take some appropriate action
detect if a packet header has been modified (maliciously or (as discussed in Section 7.7). The decision on where in the
otherwise) and if so, take some appropriate action (as discussed network to apply integrity protection is part of the DetNet system
in Section 7.7). The decision on where in the network to apply design, and the implementation of the protection method itself is
integrity protection is part of the DetNet system design, and the a part of a DetNet component design.
implementation of the protection method itself is a part of a
DetNet component design.
The most common technique for detecting header modification is the The most common technique for detecting header modification is the
use of a Message Authentication Code (MAC) (for examples see use of a Message Authentication Code (MAC) (see Section 10 for
Section 10). The MAC can be distributed either in-line (included examples). The MAC can be distributed either in line (included in
in the same packet) or via a side channel. Of these, the in-line the same packet) or via a side channel. Of these, the in-line
method is generally preferred due to the low latency that may be method is generally preferred due to the low latency that may be
required on DetNet flows and the relative complexity and required on DetNet flows and the relative complexity and
computational overhead of a sideband approach. computational overhead of a sideband approach.
There are different levels of security available for integrity There are different levels of security available for integrity
protection, ranging from the basic ability to detect if a header protection, ranging from the basic ability to detect if a header
has been corrupted in transit (no malicious attack) to stopping a has been corrupted in transit (no malicious attack) to stopping a
skilled and determined attacker capable of both subtly modifying skilled and determined attacker capable of both subtly modifying
fields in the headers as well as updating an unkeyed checksum. fields in the headers as well as updating an unkeyed checksum.
Common for all are the 2 steps that need to be performed in both Common for all are the 2 steps that need to be performed in both
ends. The first is computing the checksum or MAC. The ends. The first is computing the checksum or MAC. The
corresponding verification step must perform the same steps before corresponding verification step must perform the same steps before
comparing the provided with the computed value. Only then can the comparing the provided with the computed value. Only then can the
receiver be reasonably sure that the header is authentic. receiver be reasonably sure that the header is authentic.
The most basic protection mechanism consists of computing a simple The most basic protection mechanism consists of computing a simple
checksum of the header fields and provide it to the next entity in checksum of the header fields and providing it to the next entity
the packets path for verification. Using a MAC combined with a in the packets path for verification. Using a MAC combined with a
secret key provides the best protection against modification and secret key provides the best protection against Modification and
replication attacks (see Section 5.2.2 and Section 5.2.4). This Replication attacks (see Sections 5.2.2 and 5.2.4). This MAC
MAC usage needs to be part of a security association that is usage needs to be part of a security association that is
established and managed by a security association protocol (such established and managed by a security association protocol (such
as IKEv2 for IPsec security associations). Integrity protection as IKEv2 for IPsec security associations). Integrity protection
in the controller plane is discussed in Section 7.6. The secret in the controller plane is discussed in Section 7.6. The secret
key, regardless of MAC used, must be protected from falling into key, regardless of the MAC used, must be protected from falling
the hands of unauthorized users. Once key management becomes a into the hands of unauthorized users. Once key management becomes
topic, it is important to understand that this is a delicate a topic, it is important to understand that this is a delicate
process and should not be undertaken lightly. BCP 107 [RFC4107] process and should not be undertaken lightly. BCP 107 [BCP107]
provides best practices in this regard. provides best practices in this regard.
DetNet system and/or component designers need to be aware of these DetNet system and/or component designers need to be aware of these
distinctions and enforce appropriate integrity protection distinctions and enforce appropriate integrity-protection
mechanisms as needed based on a threat analysis. Note that adding mechanisms as needed based on a threat analysis. Note that adding
integrity protection mechanisms may introduce latency, thus many integrity-protection mechanisms may introduce latency; thus, many
of the same considerations in Section 7.5.1 also apply here. of the same considerations in Section 7.5.1 also apply here.
Packet Sequence Number Integrity Considerations Packet Sequence Number Integrity Considerations: The use of PREOF in
a DetNet implementation implies the use of a sequence number for
The use of PREOF in a DetNet implementation implies the use of a each packet. There is a trust relationship between the component
sequence number for each packet. There is a trust relationship that adds the sequence number and the component that removes the
between the component that adds the sequence number and the sequence number. The sequence number may be end-to-end source to
component that removes the sequence number. The sequence number destination, or it may be added/deleted by network edge
may be end-to-end source to destination, or may be added/deleted components. The adder and remover(s) have the trust relationship
by network edge components. The adder and remover(s) have the because they are the ones that ensure that the sequence numbers
trust relationship because they are the ones that ensure that the are not modifiable. Thus, sequence numbers can be protected by
sequence numbers are not modifiable. Thus, sequence numbers can using authenticated encryption or by a MAC without using
be protected by using authenticated encryption, or by a MAC encryption. Between the adder and remover there may or may not be
without using encryption. Between the adder and remover there may replication and elimination functions. The elimination functions
or may not be replication and elimination functions. The must be able to see the sequence numbers. Therefore, if
elimination functions must be able to see the sequence numbers. encryption is done between adders and removers, it must not
Therefore, if encryption is done between adders and removers it obscure the sequence number. If the sequence removers and the
must not obscure the sequence number. If the sequence removers eliminators are in the same physical component, it may be possible
and the eliminators are in the same physical component, it may be to obscure the sequence number; however, that is a layer violation
possible to obscure the sequence number, however that is a layer and is not recommended practice.
violation, and is not recommended practice. Note: At the time of
this writing, PREOF is not defined for the IP data plane.
Related attacks | Note: At the time of this writing, PREOF is not defined for
| the IP data plane.
Integrity protection mitigates attacks related to modification and Related attacks: Integrity protection mitigates attacks related to
tampering, including the attacks described in Section 5.2.2 and modification and tampering, including the attacks described in
Section 5.2.4. Sections 5.2.2 and 5.2.4.
7.3. DetNet Node Authentication 7.3. DetNet Node Authentication
Description Description: Authentication verifies the identity of DetNet nodes
(including DetNet Controller Plane nodes), and this enables
Authentication verifies the identity of DetNet nodes (including mitigation of Spoofing attacks. While integrity protection
DetNet Controller Plane nodes), and this enables mitigation of (Section 7.2) prevents intermediate nodes from modifying
spoofing attacks. While integrity protection ( Section 7.2) information, authentication can provide traffic origin
prevents intermediate nodes from modifying information, verification, i.e., to verify that each packet in a DetNet flow is
authentication can provide traffic origin verification, i.e. to from a known source. Although node authentication and integrity
verify that each packet in a DetNet flow is from a known source. protection are two different goals of a security protocol, in most
Although node authentication and integrity protection are two cases, a common protocol (such as IPsec [RFC4301] or MACsec
different goals of a security protocol, in most cases a common [IEEE802.1AE-2018]) is used for achieving both purposes.
protocol (such as IPsec [RFC4301] or MACsec [IEEE802.1AE-2018]) is
used for achieving both purposes.
Related attacks
DetNet node authentication is used to mitigate attacks related to
spoofing, including the attacks of Section 5.2.2, and
Section 5.2.4.
7.4. Dummy Traffic Insertion
Description Related attacks: DetNet node authentication is used to mitigate
attacks related to spoofing, including the attacks of Sections
5.2.2 and 5.2.4.
With some queueing methods such as [IEEE802.1Qch-2017] it is 7.4. Synthetic Traffic Insertion
possible to introduce dummy traffic in order to regularize the
timing of packet transmission. This will subsequently reduce the
value of passive monitoring from internal threats (see Section 5)
as it will be much more difficult to associate discrete events
with particular network packets.
Related attacks Description: With some queuing methods such as [IEEE802.1Qch-2017],
it is possible to introduce synthetic traffic in order to
regularize the timing of packet transmission. (Synthetic traffic
typically consists of randomly generated packets injected in the
network to mask observable transmission patterns in the flows,
which may allow an attacker to gain insight into the content of
the flows). This can subsequently reduce the value of passive
monitoring from internal threats (see Section 5) as it will be
much more difficult to associate discrete events with particular
network packets.
Removing distinctive temporal properties of individual packets or Related attacks: Removing distinctive temporal properties of
flows can be used to mitigate against reconnaissance attacks individual packets or flows can be used to mitigate against
Section 5.2.6. For example, dummy traffic can be used to reconnaissance attacks (Section 5.2.6). For example, synthetic
synthetically maintain constant traffic rate even when no user traffic can be used to maintain constant traffic rate even when no
data is transmitted, thus making it difficult to collect user data is transmitted, thus making it difficult to collect
information about the times at which users are active, and the information about the times at which users are active and the
times at which DetNet flows are added or removed. times at which DetNet flows are added or removed.
Traffic Insertion Challenges Traffic Insertion Challenges: Once an attacker is able to monitor
the frames traversing a network to such a degree that they can
Once an attacker is able to monitor the frames traversing a differentiate between best-effort traffic and traffic belonging to
network to such a degree that they can differentiate between best- a specific DetNet flow, it becomes difficult to not reveal to the
effort traffic and traffic belonging to a specific DetNet flow, it attacker whether a given frame is valid traffic or an inserted
becomes difficult to not reveal to the attacker whether a given frame. Thus, having the DetNet components generate and remove the
frame is valid traffic or an inserted frame. Thus, having the synthetic traffic may or may not be a viable option unless certain
DetNet components generate and remove the dummy traffic may or may challenges are solved; for example, but not limited to:
not be a viable option, unless certain challenges are solved; for
example, but not limited to:
o Inserted traffic must be indistinguishable from valid stream * Inserted traffic must be indistinguishable from valid stream
traffic from the viewpoint of the attacker. traffic from the viewpoint of the attacker.
o DetNet components must be able to safely identify and remove all * DetNet components must be able to safely identify and remove
inserted traffic (and only inserted traffic). all inserted traffic (and only inserted traffic).
o The controller plane must manage where to insert and remove dummy * The controller plane must manage where to insert and remove
traffic, but this information must not be revealed to an attacker. synthetic traffic, but this information must not be revealed to
an attacker.
An alternative design is to have the insertion and removal of An alternative design is to have the insertion and removal of
dummy traffic be performed at the application layer, rather than synthetic traffic be performed at the application layer rather
by the DetNet itself. Further discussions and reading about how than by the DetNet itself. For example, the use of RTP padding
sRTP handles this can be found in [RFC6562] to reduce information leakage from variable-bit-rate audio
transmission via the Secure Real-time Transport Protocol (SRTP)
is discussed in [RFC6562].
7.5. Encryption 7.5. Encryption
Description Description: Reconnaissance attacks (Section 5.2.6) can be mitigated
to some extent through the use of encryption, thereby preventing
Reconnaissance attacks (Section 5.2.6) can be mitigated to some the attacker from accessing the packet header or contents.
extent through the use of encryption, thereby preventing the Specific encryption protocols will depend on the lower layers that
attacker from accessing the packet header or contents. Specific DetNet is forwarded over. For example, IP flows may be forwarded
encryption protocols will depend on the lower layers that DetNet over IPsec [RFC4301], and Ethernet flows may be secured using
is forwarded over. For example, IP flows may be forwarded over MACsec [IEEE802.1AE-2018].
IPsec [RFC4301], and Ethernet flows may be secured using MACsec
[IEEE802.1AE-2018].
However, despite the use of encryption, a reconnaissance attack However, despite the use of encryption, a reconnaissance attack
can provide the attacker with insight into the network, even can provide the attacker with insight into the network, even
without visibility into the packet. For example, an attacker can without visibility into the packet. For example, an attacker can
observe which nodes are communicating with which other nodes, observe which nodes are communicating with which other nodes,
including when, how often, and with how much data. In addition, including when, how often, and with how much data. In addition,
the timing of packets may be correlated in time with external the timing of packets may be correlated in time with external
events such as action of an external device. Such information may events such as action of an external device. Such information may
be used by the attacker, for example in mapping out specific be used by the attacker, for example, in mapping out specific
targets for a different type of attack at a different time. targets for a different type of attack at a different time.
DetNet nodes do not have any need to inspect the payload of any DetNet nodes do not have any need to inspect the payload of any
DetNet packets, making them data-agnostic. This means that end- DetNet packets, making them data agnostic. This means that end-
to-end encryption at the application layer is an acceptable way to to-end encryption at the application layer is an acceptable way to
protect user data. protect user data.
Note that reconnaissance is a threat that is not specific to Note that reconnaissance is a threat that is not specific to
DetNet flows, and therefore reconnaissance mitigation will DetNet flows; therefore, reconnaissance mitigation will typically
typically be analyzed and provided by a network operator be analyzed and provided by a network operator regardless of
regardless of whether DetNet flows are deployed. Thus, encryption whether DetNet flows are deployed. Thus, encryption requirements
requirements will typically not be defined in DetNet technology- will typically not be defined in DetNet technology-specific
specific specifications, but considerations of using DetNet in specifications, but considerations of using DetNet in encrypted
encrypted environments will be discussed in these specifications. environments will be discussed in these specifications. For
For example, Section 5.1.2.3. of [RFC8939] discusses flow example, Section 5.1.2.3 of [RFC8939] discusses flow
identification of DetNet flows running over IPsec. identification of DetNet flows running over IPsec.
Related attacks Related attacks: As noted above, encryption can be used to mitigate
As noted above, encryption can be used to mitigate reconnaissance reconnaissance attacks (Section 5.2.6). However, for a DetNet to
attacks ( Section 5.2.6). However, for a DetNet to provide provide differentiated quality of service on a flow-by-flow basis,
differentiated quality of service on a flow-by-flow basis, the the network must be able to identify the flows individually. This
network must be able to identify the flows individually. This implies that in a reconnaissance attack, the attacker may also be
implies that in a reconnaissance attack the attacker may also be
able to track individual flows to learn more about the system. able to track individual flows to learn more about the system.
7.5.1. Encryption Considerations for DetNet 7.5.1. Encryption Considerations for DetNet
Any compute time which is required for encryption and decryption Any compute time that is required for encryption and decryption
processing ('crypto') must be included in the flow latency processing ("crypto") must be included in the flow latency
calculations. Thus, crypto algorithms used in a DetNet must have calculations. Thus, cryptographic algorithms used in a DetNet must
bounded worst-case execution times, and these values must be used in have bounded worst-case execution times, and these values must be
the latency calculations. Fortunately, encryption and decryption used in the latency calculations. Fortunately, encryption and
operations typically are designed to have constant execution times, decryption operations typically are designed to have constant
in order to avoid side channel leakage. execution times in order to avoid side channel leakage.
Some crypto algorithms are symmetric in encode/decode time (such as Some cryptographic algorithms are symmetric in encode/decode time
AES) and others are asymmetric (such as public key algorithms). (such as AES), and others are asymmetric (such as public key
There are advantages and disadvantages to the use of either type in a algorithms). There are advantages and disadvantages to the use of
given DetNet context. The discussion in this document relates to the either type in a given DetNet context. The discussion in this
timing implications of crypto for DetNet; it is assumed that document relates to the timing implications of crypto for DetNet; it
integrity considerations are covered elsewhere in the literature. is assumed that integrity considerations are covered elsewhere in the
literature.
Asymmetrical crypto is typically not used in networks on a packet-by- Asymmetrical crypto is typically not used in networks on a packet-by-
packet basis due to its computational cost. For example, if only packet basis due to its computational cost. For example, if only
endpoint checks or checks at a small number of intermediate points endpoint checks or checks at a small number of intermediate points
are required, asymmetric crypto can be used to authenticate are required, asymmetric crypto can be used to authenticate
distribution or exchange of a secret symmetric crypto key; a distribution or exchange of a secret symmetric crypto key; a
successful check based on that key will provide traffic origin successful check based on that key will provide traffic origin
verification, as long as the key is kept secret by the participants. verification as long as the key is kept secret by the participants.
TLS (v1.3 [RFC8446], in particular section 4.1 "Key exchange") and TLS (v1.3 [RFC8446], in particular, Section 4.1 ("Key Exchange
IKEv2 [RFC6071]) are examples of this for endpoint checks. Messages")) and IKEv2 [RFC6071] are examples of this for endpoint
checks.
However, if secret symmetric keys are used for this purpose the key However, if secret symmetric keys are used for this purpose, the key
must be given to all relays, which increases the probability of a must be given to all relays, which increases the probability of a
secret key being leaked. Also, if any relay is compromised or faulty secret key being leaked. Also, if any relay is compromised or
then it may inject traffic into the flow. Group key management faulty, then it may inject traffic into the flow. Group key
protocols can be used to automate management of such symmetric keys; management protocols can be used to automate management of such
for an example in the context of IPsec, see symmetric keys; for an example in the context of IPsec, see
[I-D.ietf-ipsecme-g-ikev2]. [IPSECME-G-IKEV2].
Alternatively, asymmetric crypto can provide traffic origin Alternatively, asymmetric crypto can provide traffic origin
verification at every intermediate node. For example, a DetNet flow verification at every intermediate node. For example, a DetNet flow
can be associated with an (asymmetric) keypair, such that the private can be associated with an (asymmetric) keypair, such that the private
key is available to the source of the flow and the public key is key is available to the source of the flow and the public key is
distributed with the flow information, allowing verification at every distributed with the flow information, allowing verification at every
node for every packet. However, this is more computationally node for every packet. However, this is more computationally
expensive. expensive.
In either case, origin verification also requires replay detection as In either case, origin verification also requires replay detection as
part of the security protocol to prevent an attacker from recording part of the security protocol to prevent an attacker from recording
and resending traffic, e.g., as a denial of service attack on flow and resending traffic, e.g., as a denial-of-service attack on flow
forwarding resources. forwarding resources.
In the general case, cryptographic hygiene requires the generation of In the general case, cryptographic hygiene requires the generation of
new keys during the lifetime of an encrypted flow (e.g. see [RFC4253] new keys during the lifetime of an encrypted flow (e.g., see
section 9), and any such key generation (or key exchange) requires Section 9 of [RFC4253]), and any such key generation (or key
additional computing time which must be accounted for in the latency exchange) requires additional computing time, which must be accounted
calculations for that flow. For modern ECDH (Elliptical Curve for in the latency calculations for that flow. For modern ECDH
Diffie-Hellman) key-exchange operations (such as x25519, see (Elliptical Curve Diffie-Hellman) key-exchange operations (such as
[RFC7748]) these operations can be performed in constant x25519 [RFC7748]), these operations can be performed in constant
(predictable) time, however this is not universally true (for example (predictable) time; however, this is not universally true (for
for legacy RSA key exchange, [RFC4432]). Thus implementers should be example, for legacy RSA key exchange [RFC4432]). Thus, implementers
aware of the time properties of these algorithms and avoid algorithms should be aware of the time properties of these algorithms and avoid
that make constant-time implementation difficult or impossible. algorithms that make constant-time implementation difficult or
impossible.
7.6. Control and Signaling Message Protection 7.6. Control and Signaling Message Protection
Description Description: Control and signaling messages can be protected through
the use of any or all of encryption, authentication, and
Control and signaling messages can be protected through the use of integrity-protection mechanisms. Compared with data flows, the
any or all of encryption, authentication, and integrity protection timing constraints for controller and signaling messages may be
mechanisms. Compared with data-flows, the timing constraints for less strict, and the number of such packets may be fewer. If that
controller and signaling messages may be less strict, and the is the case in a given application, then it may enable the use of
number of such packets may be fewer. If that is the case in a asymmetric cryptography for the signing of both payload and
given application, then it may enable the use of asymmetric headers for such messages, as well as encrypting the payload.
cryptography for signing of both payload and headers for such Given that a DetNet is managed by a central controller, the use of
messages, as well as encrypting the payload. Given that a DetNet a shared public key approach for these processes is well proven.
is managed by a central controller, the use of a shared public key This is further discussed in Section 7.5.1.
approach for these processes is well-proven. This is further
discussed in Section 7.5.1.
Related attacks
These mechanisms can be used to mitigate various attacks on the Related attacks: These mechanisms can be used to mitigate various
controller plane, as described in Section 5.2.5, Section 5.2.7 and attacks on the controller plane, as described in Sections 5.2.5,
Section 5.2.5.1. 5.2.7, and 5.2.5.1.
7.7. Dynamic Performance Analytics 7.7. Dynamic Performance Analytics
Description Description: Incorporating Dynamic Performance Analytics (DPA)
implies that the DetNet design includes a performance monitoring
Incorporating Dynamic Performance Analytics ("DPA") implies that system to validate that timing guarantees are being met and to
the DetNet design includes a performance monitoring system to detect timing violations or other anomalies that may be the
validate that timing guarantees are being met and to detect timing symptom of a security attack or system malfunction. If this
violations or other anomalies that may be the symptom of a monitoring system detects unexpected behavior, it must then cause
security attack or system malfunction. If this monitoring system action to be initiated to address the situation in an appropriate
detects unexpected behavior, it must then cause action to be and timely manner, either at the data plane or controller plane or
initiated to address the situation in an appropriate and timely both in concert.
manner, either at the data plane or controller plane, or both in
concert.
The overall DPA system can thus be decomposed into the "detection" The overall DPA system can thus be decomposed into the "detection"
and "notification" functions. Although the time-specific DPA and "notification" functions. Although the time-specific DPA
performance indicators and their implementation will likely be performance indicators and their implementation will likely be
specific to a given DetNet, and as such are nascent technology at specific to a given DetNet, and as such are nascent technology at
the time of this writing, DPA is commonly used in existing the time of this writing, DPA is commonly used in existing
networks so we can make some observations on how such a system networks so we can make some observations on how such a system
might be implemented for a DetNet, given that it would need to be might be implemented for a DetNet given that it would need to be
adapted to address the time-specific performance indicators. adapted to address the time-specific performance indicators.
Detection Mechanisms Detection Mechanisms: Measurement of timing performance can be done
via "passive" or "active" monitoring, as discussed below.
Measurement of timing performance can be done via "passive" or
"active" monitoring, as discussed below.
Examples of passive monitoring strategies include Examples of passive monitoring strategies include:
* Monitoring of queue and buffer levels, e.g. via Active Queue * Monitoring of queue and buffer levels, e.g., via active queue
Management (e.g. [RFC7567] management (e.g., [RFC7567]).
* Monitoring of per-flow counters * Monitoring of per-flow counters.
* Measurement of link statistics such as traffic volume, * Measurement of link statistics such as traffic volume,
bandwidth, and QoS bandwidth, and QoS.
* Detection of dropped packets * Detection of dropped packets.
* Use of commercially available Network Monitoring tools * Use of commercially available Network Monitoring tools.
Examples of active monitoring include Examples of active monitoring include:
* In-band timing measurements (such as packet arrival times) e.g. * In-band timing measurements (such as packet arrival times),
by timestamping and packet inspection e.g., by timestamping and packet inspection.
* Use of OAM. For DetNet-specific OAM considerations see * Use of OAM. For DetNet-specific OAM considerations, see
[I-D.ietf-detnet-ip-oam], [I-D.ietf-detnet-mpls-oam]. Note: At [DETNET-IP-OAM] and [DETNET-MPLS-OAM]. Note: At the time of
the time of this writing, specifics of DPA have not been this writing, specifics of DPA have not been developed for the
developed for the DetNet OAM, but could be a subject for future DetNet OAM but could be a subject for future investigation.
investigation
* For OAM for Ethernet specifically, see also Connectivity Fault - For OAM for Ethernet specifically, see also Connectivity
Management (CFM, [IEEE802.1Q]) which defines protocols and Fault Management (CFM [IEEE802.1Q]), which defines protocols
practices for OAM for paths through 802.1 bridges and LANs and practices for OAM for paths through 802.1 bridges and
LANs.
* Out-of-band detection. following the data path or parts of a * Out-of-band detection. Following the data path or parts of a
data path, for example Bidirectional Forwarding Detection (BFD, data path, for example, Bidirectional Forwarding Detection
e.g. [RFC5880]) (BFD, e.g., [RFC5880]).
Note that for some measurements (e.g. packet delay) it may be Note that for some measurements (e.g., packet delay), it may be
necessary to make and reconcile measurements from more than one necessary to make and reconcile measurements from more than one
physical location (e.g. a source and destination), possibly in physical location (e.g., a source and destination), possibly in
both directions, in order to arrive at a given performance both directions, in order to arrive at a given performance
indicator value. indicator value.
Notification Mechanisms Notification Mechanisms: Making DPA measurement results available at
the right place(s) and time(s) to effect timely response can be
Making DPA measurement results available at the right place(s) and challenging. Two notification mechanisms that are in general use
time(s) to effect timely response can be challenging. Two are NETCONF/YANG Notifications and the proprietary local telemetry
notification mechanisms that are in general use are Netconf/YANG interfaces provided with components from some vendors. The
Notifications (e.g. [RFC5880]) and the proprietary local Constrained Application Protocol (CoAP) Observe Option [RFC7641]
telemetry interfaces provided with components from some vendors. could also be relevant to such scenarios.
The CoAP Observe Option ([RFC7641]) could also be relevant to such
scenarios.
At the time of this writing YANG Notifications are not addressed At the time of this writing, YANG Notifications are not addressed
by the DetNet YANG drafts, however this may be a topic for future by the DetNet YANG documents; however, this may be a topic for
work. It is possible that some of the passive mechanisms could be future work. It is possible that some of the passive mechanisms
covered by notifications from non-DetNet-specific YANG modules; could be covered by notifications from non-DetNet-specific YANG
for example if there is OAM or other performance monitoring that modules; for example, if there is OAM or other performance
can monitor delay bounds then that could have its own associated monitoring that can monitor delay bounds, then that could have its
YANG model which could be relevant to DetNet, for example some own associated YANG data model, which could be relevant to DetNet,
"threshold" values for timing measurement notifications. for example, some "threshold" values for timing measurement
notifications.
At the time of this writing there is an IETF Working Group for At the time of this writing, there is an IETF Working Group for
network/performance monitoring (IP Performance Measurement, ippm). network/performance monitoring (IP Performance Metrics (IPPM)).
See also previous work by the completed Remote Network Monitoring See also previous work by the completed Remote Network Monitoring
Working Group (rmonmib). See also [RFC6632], An Overview of the Working Group (RMONMIB). See also "An Overview of the IETF
IETF Network Management Standards. Network Management Standards", [RFC6632].
Vendor-specific local telemetry may be available on some Vendor-specific local telemetry may be available on some
commercially available systems, whereby the system can be commercially available systems, whereby the system can be
programmed (via a proprietary dedicated port and API) to monitor programmed (via a proprietary dedicated port and API) to monitor
and report on specific conditions, based on both passive and and report on specific conditions, based on both passive and
active measurements. active measurements.
Related attacks Related attacks: Performance analytics can be used to detect various
attacks, including the ones described in Section 5.2.1 (Delay
Performance analytics can be used to detect various attacks, attack), Section 5.2.3 (Resource Segmentation attack), and
including the ones described in Section 5.2.1 (Delay Attack), Section 5.2.7 (Time-Synchronization attack). Once detection and
Section 5.2.3 (Resource Segmentation Attack), and Section 5.2.7 notification have occurred, the appropriate action can be taken to
(Time Synchronization Attack). Once detection and notification mitigate the threat.
have occurred, the appropriate action can be taken to mitigate the
threat.
For example, in the case of data plane delay attacks, one possible For example, in the case of data plane Delay attacks, one possible
mitigation is to timestamp the data at the source, and timestamp mitigation is to timestamp the data at the source and timestamp it
it again at the destination, and if the resulting latency does not again at the destination, and if the resulting latency does not
meet the service agreement, take appropriate action. Note that meet the service agreement, take appropriate action. Note that
DetNet specifies packet sequence numbering, however it does not DetNet specifies packet sequence numbering; however, it does not
specify use of packet timestamps, although they may be used by the specify use of packet timestamps, although they may be used by the
underlying transport (for example TSN, [IEEE802.1BA]) to provide underlying transport (for example, TSN [IEEE802.1BA]) to provide
the service. the service.
7.8. Mitigation Summary 7.8. Mitigation Summary
The following table maps the attacks of Section 5, Security Threats, The following table maps the attacks of Section 5 (Security Threats)
to the impacts of Section 6, Security Threat Impacts, and to the to the impacts of Section 6 (Security Threat Impacts) and to the
mitigations of the current section. Each row specifies an attack, mitigations of the current section. Each row specifies an attack,
the impact of this attack if it is successfully implemented, and the impact of this attack if it is successfully implemented, and
possible mitigation methods. possible mitigation methods.
+----------------------+---------------------+---------------------+ +======================+======================+=====================+
| Attack | Impact | Mitigations | | Attack | Impact | Mitigations |
+----------------------+---------------------+---------------------+ +======================+======================+=====================+
|Delay Attack |-Non-deterministic |-Path redundancy | | Delay Attack | * Non-deterministic | * Path redundancy |
| | delay |-Performance | | | delay | |
| |-Data disruption | analytics | | | | * Performance |
| |-Increased resource | | | | * Data disruption | analytics |
| | consumption | | | | | |
+----------------------+---------------------+---------------------+ | | * Increased | |
|Reconnaissance |-Enabler for other |-Encryption | | | resource | |
| | attacks |-Dummy traffic | | | consumption | |
| | | insertion | +----------------------+----------------------+---------------------+
+----------------------+---------------------+---------------------+ | Reconnaissance | * Enabler for other | * Encryption |
|DetNet Flow Modificat-|-Increased resource |-Path redundancy | | | attacks | |
|ion or Spoofing | consumption |-Integrity protection| | | | * Synthetic |
| |-Data disruption |-DetNet Node | | | | traffic |
| | | authentication | | | | insertion |
+----------------------+---------------------+---------------------+ +----------------------+----------------------+---------------------+
|Inter-Segment Attack |-Increased resource |-Path redundancy | | DetNet Flow | * Increased | * Path redundancy |
| | consumption |-Performance | | Modification or | resource | |
| |-Data disruption | analytics | | Spoofing | consumption | * Integrity |
+----------------------+---------------------+---------------------+ | | | protection |
|Replication: Increased|-All impacts of other|-Integrity protection| | | * Data disruption | |
|attack surface | attacks |-DetNet Node | | | | * DetNet Node |
| | | authentication | | | | authentication |
| | |-Encryption | +----------------------+----------------------+---------------------+
+----------------------+---------------------+---------------------+ | Inter-segment Attack | * Increased | * Path redundancy |
|Replication-related |-Non-deterministic |-Integrity protection| | | resource | |
|Header Manipulation | delay |-DetNet Node | | | consumption | * Performance |
| |-Data disruption | authentication | | | | analytics |
+----------------------+---------------------+---------------------+ | | * Data disruption | |
|Path Manipulation |-Enabler for other |-Control and | +----------------------+----------------------+---------------------+
| | attacks | signaling message | | Replication: | * All impacts of | * Integrity |
| | | protection | | Increased Attack | other attacks | protection |
+----------------------+---------------------+---------------------+ | Resource | | |
|Path Choice: Increased|-All impacts of other|-Control and | | | | * DetNet Node |
|Attack Surface | attacks | signaling message | | | | authentication |
| | | protection | | | | |
+----------------------+---------------------+---------------------+ | | | * Encryption |
|Control or Signaling |-Increased resource |-Control and | +----------------------+----------------------+---------------------+
|Packet Modification | consumption | signaling message | | Replication-Related | * Non-deterministic | * Integrity |
| |-Non-deterministic | protection | | Header Manipulation | delay | protection |
| | delay | | | | | |
| |-Data disruption | | | | * Data disruption | * DetNet Node |
+----------------------+---------------------+---------------------+ | | | authentication |
|Control or Signaling |-Increased resource |-Control and | +----------------------+----------------------+---------------------+
|Packet Injection | consumption | signaling message | | Path Manipulation | * Enabler for other | * Control and |
| |-Non-deterministic | protection | | | attacks | signaling |
| | delay | | | | | message |
| |-Data disruption | | | | | protection |
+----------------------+---------------------+---------------------+ +----------------------+----------------------+---------------------+
|Attacks on Time |-Non-deterministic |-Path redundancy | | Path Choice: | * All impacts of | * Control and |
|Synchronization | delay |-Control and | | Increased Attack | other attacks | signaling |
|Mechanisms |-Increased resource | signaling message | | Surface | | message |
| | consumption | protection | | | | protection |
| |-Data disruption |-Performance | +----------------------+----------------------+---------------------+
| | | analytics | | Control or Signaling | * Increased | * Control and |
+----------------------+---------------------+---------------------+ | Packet Modification | resource | signaling |
| | consumption | message |
| | | protection |
| | * Non-deterministic | |
| | delay | |
| | | |
| | * Data disruption | |
+----------------------+----------------------+---------------------+
| Control or Signaling | * Increased | * Control and |
| Packet Injection | resource | signaling |
| | consumption | message |
| | | protection |
| | * Non-deterministic | |
| | delay | |
| | | |
| | * Data disruption | |
+----------------------+----------------------+---------------------+
| Attacks on Time- | * Non-deterministic | * Path redundancy |
| Synchronization | delay | |
| Mechanisms | | * Control and |
| | * Increased | signaling |
| | resource | message |
| | consumption | protection |
| | | |
| | * Data disruption | * Performance |
| | | analytics |
+----------------------+----------------------+---------------------+
Figure 3: Mapping Attacks to Impact and Mitigations Table 3: Mapping Attacks to Impact and Mitigations
8. Association of Attacks to Use Cases 8. Association of Attacks to Use Cases
Different attacks can have different impact and/or mitigation Different attacks can have different impact and/or mitigation
depending on the use case, so we would like to make this association depending on the use case, so we would like to make this association
in our analysis. However since there is a potentially unbounded list in our analysis. However, since there is a potentially unbounded
of use cases, we categorize the attacks with respect to the common list of use cases, we categorize the attacks with respect to the
themes of the use cases as identified in the Use Case Common Themes common themes of the use cases as identified in Section 11 of
section of the DetNet Use Cases [RFC8578]. [RFC8578].
See also Figure 2 for a mapping of the impact of attacks per use case See also Table 2 for a mapping of the impact of attacks per use case
by industry. by industry.
8.1. Association of Attacks to Use Case Common Themes 8.1. Association of Attacks to Use Case Common Themes
In this section we review each theme and discuss the attacks that are In this section, we review each theme and discuss the attacks that
applicable to that theme, as well as anything specific about the are applicable to that theme, as well as anything specific about the
impact and mitigations for that attack with respect to that theme. impact and mitigations for that attack with respect to that theme.
The table Figure 5, Mapping Between Themes and Attacks, then provides Table 5, Mapping between Themes and Attacks, then provides a summary
a summary of the attacks that are applicable to each theme. of the attacks that are applicable to each theme.
8.1.1. Sub-Network Layer 8.1.1. Sub-network Layer
DetNet is expected to run over various transmission mediums, with DetNet is expected to run over various transmission mediums, with
Ethernet being the first identified. Attacks such as Delay or Ethernet being the first identified. Attacks such as Delay or
Reconnaissance might be implemented differently on a different Reconnaissance might be implemented differently on a different
transmission medium, however the impact on the DetNet as a whole transmission medium; however, the impact on the DetNet as a whole
would be essentially the same. We thus conclude that all attacks and would be essentially the same. We thus conclude that all attacks and
impacts that would be applicable to DetNet over Ethernet (i.e. all impacts that would be applicable to DetNet over Ethernet (i.e., all
those named in this document) would also be applicable to DetNet over those named in this document) would also be applicable to DetNet over
other transmission mediums. other transmission mediums.
With respect to mitigations, some methods are specific to the With respect to mitigations, some methods are specific to the
Ethernet medium, for example time-aware scheduling using 802.1Qbv Ethernet medium, for example, time-aware scheduling using 802.1Qbv
[IEEE802.1Qbv-2015] can protect against excessive use of bandwidth at [IEEE802.1Qbv-2015] can protect against excessive use of bandwidth at
the ingress - for other mediums, other mitigations would have to be the ingress -- for other mediums, other mitigations would have to be
implemented to provide analogous protection. implemented to provide analogous protection.
8.1.2. Central Administration 8.1.2. Central Administration
A DetNet network can be controlled by a centralized network A DetNet network can be controlled by a centralized network
configuration and control system. Such a system may be in a single configuration and control system. Such a system may be in a single
central location, or it may be distributed across multiple control central location, or it may be distributed across multiple control
entities that function together as a unified control system for the entities that function together as a unified control system for the
network. network.
All attacks named in this document which are relevant to controller All attacks named in this document that are relevant to controller
plane packets (and the controller itself) are relevant to this theme, plane packets (and the controller itself) are relevant to this theme,
including Path Manipulation, Path Choice, Control Packet Modification including Path Manipulation, Path Choice, Control Packet Modification
or Injection, Reconnaissance and Attacks on Time Synchronization or Injection, Reconnaissance, and Attacks on Time-Synchronization
Mechanisms. Mechanisms.
8.1.3. Hot Swap 8.1.3. Hot Swap
A DetNet network is not expected to be "plug and play" - it is A DetNet network is not expected to be "plug and play"; it is
expected that there is some centralized network configuration and expected that there is some centralized network configuration and
control system. However, the ability to "hot swap" components (e.g. control system. However, the ability to "hot swap" components (e.g.,
due to malfunction) is similar enough to "plug and play" that this due to malfunction) is similar enough to "plug and play" that this
kind of behavior may be expected in DetNet networks, depending on the kind of behavior may be expected in DetNet networks, depending on the
implementation. implementation.
An attack surface related to Hot Swap is that the DetNet network must An attack surface related to hot swap is that the DetNet network must
at least consider input at runtime from components that were not part at least consider input at runtime from components that were not part
of the initial configuration of the network. Even a "perfect" (or of the initial configuration of the network. Even a "perfect" (or
"hitless") replacement of a component at runtime would not "hitless") replacement of a component at runtime would not
necessarily be ideal, since presumably one would want to distinguish necessarily be ideal, since presumably one would want to distinguish
it from the original for OAM purposes (e.g. to report hot swap of a it from the original for OAM purposes (e.g., to report hot swap of a
failed component). failed component).
This implies that an attack such as Flow Modification, Spoofing or This implies that an attack such as Flow Modification, Spoofing, or
Inter-segment (which could introduce packets from a "new" component, Inter-segment (which could introduce packets from a "new" component,
i.e. one heretofore unknown on the network) could be used to exploit i.e., one heretofore unknown on the network) could be used to exploit
the need to consider such packets (as opposed to rejecting them out the need to consider such packets (as opposed to rejecting them out
of hand as one would do if one did not have to consider introduction of hand as one would do if one did not have to consider introduction
of a new component). of a new component).
To mitigate this situation, deployments should provide a method for To mitigate this situation, deployments should provide a method for
dynamic and secure registration of new components, and (possibly dynamic and secure registration of new components, and (possibly
manual) deregistration and re-keying of retired components. This manual) deregistration and re-keying of retired components. This
would avoid the situation in which the network must accommodate would avoid the situation in which the network must accommodate
potentially insecure packet flows from unknown components. potentially insecure packet flows from unknown components.
Similarly if the network was designed to support runtime replacement Similarly, if the network was designed to support runtime replacement
of a clock component, then presence (or apparent presence) and thus of a clock component, then presence (or apparent presence) and thus
consideration of packets from a new such component could affect the consideration of packets from a new such component could affect the
network, or the time synchronization of the network, for example by network, or the time synchronization of the network, for example, by
initiating a new Best Master Clock selection process. These types of initiating a new Best Master Clock selection process. These types of
attacks should therefore be considered when designing hot swap type attacks should therefore be considered when designing hot-swap-type
functionality (see [RFC7384]). functionality (see [RFC7384]).
8.1.4. Data Flow Information Models 8.1.4. Data Flow Information Models
DetNet specifies new YANG models ([I-D.ietf-detnet-yang])which may DetNet specifies new YANG data models [DETNET-YANG] that may present
present new attack surfaces. Per IETF guidelines, security new attack surfaces. Per IETF guidelines, security considerations
considerations for any YANG model are expected to be part of the YANG for any YANG data model are expected to be part of the YANG data
model specification, as described in [IETF_YANG_SEC]. model specification, as described in [IETF-YANG-SEC].
8.1.5. L2 and L3 Integration 8.1.5. L2 and L3 Integration
A DetNet network integrates Layer 2 (bridged) networks (e.g. AVB/TSN A DetNet network integrates Layer 2 (bridged) networks (e.g., AVB/TSN
LAN) and Layer 3 (routed) networks (e.g. IP) via the use of well- LAN) and Layer 3 (routed) networks (e.g., IP) via the use of well-
known protocols such as IP, MPLS Pseudowire, and Ethernet. Various known protocols such as IP, MPLS Pseudowire, and Ethernet. Various
DetNet drafts address many specific aspects of Layer 2 and Layer 3 DetNet documents address many specific aspects of Layer 2 and Layer 3
integration within a DetNet, and these are not individually integration within a DetNet, and these are not individually
referenced here; security considerations for those aspects are referenced here; security considerations for those aspects are
covered within those drafts or within the related subsections of the covered within those documents or within the related subsections of
present document. the present document.
Please note that although there are no entries in the L2 and L3 Please note that although there are no entries in the L2 and L3
Integration line of the Mapping Between Themes and Attacks table Integration line of the Mapping between Themes and Attacks table
Figure 4, this does not imply that there could be no relevant attacks (Table 5), this does not imply that there could be no relevant
related to L2-L3 integration. attacks related to L2-L3 integration.
8.1.6. End-to-End Delivery 8.1.6. End-to-End Delivery
Packets that are part of a resource-reserved DetNet flow are not to Packets that are part of a resource-reserved DetNet flow are not to
be dropped by the DetNet due to congestion. Packets may however be be dropped by the DetNet due to congestion. Packets may however be
dropped for intended reasons, for example security measures. For dropped for intended reasons, for example, security measures. For
example, consider the case in which a packet becomes corrupted example, consider the case in which a packet becomes corrupted
(whether incidentally or maliciously) such that the resulting flow ID (whether incidentally or maliciously) such that the resulting flow ID
incidentally matches the flow ID of another DetNet flow, potentially incidentally matches the flow ID of another DetNet flow, potentially
resulting in additional unauthorized traffic on the latter. In such resulting in additional unauthorized traffic on the latter. In such
a case it may be a security requirement that the system report and/or a case, it may be a security requirement that the system report and/
take some defined action, perhaps when a packet drop count threshold or take some defined action, perhaps when a packet drop count
has been reached (see also Section 7.7). threshold has been reached (see also Section 7.7).
A data plane attack may force packets to be dropped, for example as a A data plane attack may force packets to be dropped, for example, as
result of a Delay attack, Replication/Elimination attack, or Flow a result of a Delay attack, Replication/Elimination attack, or Flow
Modification attack. Modification attack.
The same result might be obtained by a controller plane attack, e.g. The same result might be obtained by a Controller plane attack, e.g.,
Path Manipulation or Signaling Packet Modification. Path Manipulation or Signaling Packet Modification.
An attack may also cause packets that should not be delivered to be An attack may also cause packets that should not be delivered to be
delivered, such as by forcing packets from one (e.g. replicated) path delivered, such as by forcing packets from one (e.g., replicated)
to be preferred over another path when they should not be path to be preferred over another path when they should not be
(Replication attack), or by Flow Modification, or by Path Choice or (Replication attack), or by Flow Modification, or Path Choice or
Packet Injection. A Time Synchronization attack could cause a system Packet Injection. A Time-Synchronization attack could cause a system
that was expecting certain packets at certain times to accept that was expecting certain packets at certain times to accept
unintended packets based on compromised system time or time windowing unintended packets based on compromised system time or time windowing
in the scheduler. in the scheduler.
8.1.7. Replacement for Proprietary Fieldbuses and Ethernet-based 8.1.7. Replacement for Proprietary Fieldbuses and Ethernet-Based
Networks Networks
There are many proprietary "field buses" used in Industrial and other There are many proprietary "fieldbuses" used in Industrial and other
industries, as well as proprietary non-interoperable deterministic industries, as well as proprietary non-interoperable deterministic
Ethernet-based networks. DetNet is intended to provide an open- Ethernet-based networks. DetNet is intended to provide an open-
standards-based alternative to such buses/networks. In cases where a standards-based alternative to such buses/networks. In cases where a
DetNet intersects with such fieldbuses/networks or their protocols, DetNet intersects with such fieldbuses/networks or their protocols,
such as by protocol emulation or access via a gateway, new attack such as by protocol emulation or access via a gateway, new attack
surfaces can be opened. surfaces can be opened.
For example an Inter-Segment or Controller plane attack such as Path For example, an Inter-segment or Controller plane attack such as Path
Manipulation, Path Choice or Control Packet Modification/Injection Manipulation, Path Choice, or Control Packet Modification/Injection
could be used to exploit commands specific to such a protocol, or could be used to exploit commands specific to such a protocol or that
that are interpreted differently by the different protocols or are interpreted differently by the different protocols or gateway.
gateway.
8.1.8. Deterministic vs Best-Effort Traffic 8.1.8. Deterministic vs. Best-Effort Traffic
Most of the themes described in this document address OT (reserved) Most of the themes described in this document address OT (reserved)
DetNet flows - this item is intended to address issues related to IT DetNet flows -- this item is intended to address issues related to IT
traffic on a DetNet. traffic on a DetNet.
DetNet is intended to support coexistence of time-sensitive DetNet is intended to support coexistence of time-sensitive
operational (OT, deterministic) traffic and information (IT, "best operational (OT, deterministic) traffic and informational (IT, "best
effort") traffic on the same ("unified") network. effort") traffic on the same ("unified") network.
With DetNet, this coexistence will become more common, and With DetNet, this coexistence will become more common, and
mitigations will need to be established. The fact that the IT mitigations will need to be established. The fact that the IT
traffic on a DetNet is limited to a corporate controlled network traffic on a DetNet is limited to a corporate-controlled network
makes this a less difficult problem compared to being exposed to the makes this a less difficult problem compared to being exposed to the
open Internet, however this aspect of DetNet security should not be open Internet; however, this aspect of DetNet security should not be
underestimated. underestimated.
An Inter-segment attack can flood the network with IT-type traffic An Inter-segment attack can flood the network with IT-type traffic
with the intent of disrupting handling of IT traffic, and/or the goal with the intent of disrupting the handling of IT traffic and/or the
of interfering with OT traffic. Presumably if the DetNet flow goal of interfering with OT traffic. Presumably, if the DetNet flow
reservation and isolation of the DetNet is well-designed (better- reservation and isolation of the DetNet is well designed (better-
designed than the attack) then interference with OT traffic should designed than the attack), then interference with OT traffic should
not result from an attack that floods the network with IT traffic. not result from an attack that floods the network with IT traffic.
The handling of IT traffic (i.e. traffic which by definition is not The handling of IT traffic (i.e., traffic that by definition is not
guaranteed any given deterministic service properties) by the DetNet guaranteed any given deterministic service properties) by the DetNet
will by definition not be given the DetNet-specific protections will by definition not be given the DetNet-specific protections
provided to DetNet (resource-reserved) flows. The implication is provided to DetNet (resource-reserved) flows. The implication is
that the IT traffic on the DetNet network will necessarily have its that the IT traffic on the DetNet network will necessarily have its
own specific set of product (component or system) requirements for own specific set of product (component or system) requirements for
protection against attacks such as DOS; presumably they will be less protection against attacks such as DoS; presumably they will be less
stringent than those for OT flows, but nonetheless component and stringent than those for OT flows, but nonetheless, component and
system designers must employ whatever mitigations will meet the system designers must employ whatever mitigations will meet the
specified security requirements for IT traffic for the given specified security requirements for IT traffic for the given
component or DetNet. component or DetNet.
The network design as a whole also needs to consider possible The network design as a whole also needs to consider possible
application-level dependencies of "OT"-type applications on services application-level dependencies of OT-type applications on services
provided by the "IT part" of the network; for example, does the OT provided by the IT part of the network; for example, does the OT
application depend on IT network services such as DNS or OAM? If application depend on IT network services such as DNS or OAM? If
such dependencies exist, how are malicious packet flows handled? such dependencies exist, how are malicious packet flows handled?
Such considerations are typically outside the scope of DetNet proper, Such considerations are typically outside the scope of DetNet proper,
but nonetheless need to be addressed in the overall DetNet network but nonetheless need to be addressed in the overall DetNet network
design for a given use case. design for a given use case.
8.1.9. Deterministic Flows 8.1.9. Deterministic Flows
Reserved bandwidth data flows (deterministic flows) must provide the Reserved bandwidth data flows (deterministic flows) must provide the
allocated bandwidth, and must be isolated from each other. allocated bandwidth and must be isolated from each other.
A Spoofing or Inter-segment attack which adds packet traffic to a A Spoofing or Inter-segment attack that adds packet traffic to a
bandwidth-reserved DetNet flow could cause that flow to occupy more bandwidth-reserved DetNet flow could cause that flow to occupy more
bandwidth than it was allocated, resulting in interference with other bandwidth than it was allocated, resulting in interference with other
DetNet flows. DetNet flows.
A Flow Modification or Spoofing or Header Manipulation or Control A Flow Modification, Spoofing, Header Manipulation, or Control Packet
Packet Modification attack could cause packets from one flow to be Modification attack could cause packets from one flow to be directed
directed to another flow, thus breaching isolation between the flows. to another flow, thus breaching isolation between the flows.
8.1.10. Unused Reserved Bandwidth 8.1.10. Unused Reserved Bandwidth
If bandwidth reservations are made for a DetNet flow but the If bandwidth reservations are made for a DetNet flow but the
associated bandwidth is not used at any point in time, that bandwidth associated bandwidth is not used at any point in time, that bandwidth
is made available on the network for best-effort traffic. However, is made available on the network for best-effort traffic. However,
note that security considerations for best-effort traffic on a DetNet note that security considerations for best-effort traffic on a DetNet
network is out of scope of the present document, provided that any network is out of scope of the present document, provided that any
such attacks on best-effort traffic do not affect performance for such attacks on best-effort traffic do not affect performance for
DetNet OT traffic. DetNet OT traffic.
skipping to change at page 42, line 44 skipping to change at line 1990
ecosystem in which multiple vendors can create interoperable ecosystem in which multiple vendors can create interoperable
products, thus promoting component diversity and potentially higher products, thus promoting component diversity and potentially higher
numbers of each component manufactured. Toward that end, the numbers of each component manufactured. Toward that end, the
security measures and protocols discussed in this document are security measures and protocols discussed in this document are
intended to encourage interoperability. intended to encourage interoperability.
Given that the DetNet specifications are unambiguously written and Given that the DetNet specifications are unambiguously written and
that the implementations are accurate, the property of that the implementations are accurate, the property of
interoperability should not in and of itself cause security concerns; interoperability should not in and of itself cause security concerns;
however, flaws in interoperability between components could result in however, flaws in interoperability between components could result in
security weaknesses. The network operator as well as system and security weaknesses. The network operator, as well as system and
component designer can all contribute to reducing such weaknesses component designers, can all contribute to reducing such weaknesses
through interoperability testing. through interoperability testing.
8.1.12. Cost Reductions 8.1.12. Cost Reductions
The DetNet network specifications are intended to enable an ecosystem The DetNet network specifications are intended to enable an ecosystem
in which multiple vendors can create interoperable products, thus in which multiple vendors can create interoperable products, thus
promoting higher numbers of each component manufactured, promoting promoting higher numbers of each component manufactured, promoting
cost reduction and cost competition among vendors. cost reduction and cost competition among vendors.
This envisioned breadth of DetNet-enabled products is in general a This envisioned breadth of DetNet-enabled products is in general a
positive factor, however implementation flaws in any individual positive factor; however, implementation flaws in any individual
component can present an attack surface. In addition, implementation component can present an attack surface. In addition, implementation
differences between components from different vendors can result in differences between components from different vendors can result in
attack surfaces (resulting from their interaction) which may not attack surfaces (resulting from their interaction) that may not exist
exist in any individual component. in any individual component.
Network operators can mitigate such concerns through sufficient Network operators can mitigate such concerns through sufficient
product and interoperability testing. product and interoperability testing.
8.1.13. Insufficiently Secure Components 8.1.13. Insufficiently Secure Components
The DetNet network specifications are intended to enable an ecosystem The DetNet network specifications are intended to enable an ecosystem
in which multiple vendors can create interoperable products, thus in which multiple vendors can create interoperable products, thus
promoting component diversity and potentially higher numbers of each promoting component diversity and potentially higher numbers of each
component manufactured. However this raises the possibility that a component manufactured. However, this raises the possibility that a
vendor might repurpose for DetNet applications a hardware or software vendor might repurpose for DetNet applications a hardware or software
component that was originally designed for operation in an isolated component that was originally designed for operation in an isolated
OT network, and thus may not have been designed to be sufficiently OT network and thus may not have been designed to be sufficiently
secure, or secure at all, against the sorts of attacks described in secure, or secure at all, against the sorts of attacks described in
this document. Deployment of such a component on a DetNet network this document. Deployment of such a component on a DetNet network
that is intended to be highly secure may present an attack surface; that is intended to be highly secure may present an attack surface;
thus the DetNet network operator may need to take specific actions to thus, the DetNet network operator may need to take specific actions
protect such components, for example by implementing a secure to protect such components, for example, by implementing a secure
interface (such as a firewall) to isolate the component from the interface (such as a firewall) to isolate the component from the
threats that may be present in the greater network. threats that may be present in the greater network.
8.1.14. DetNet Network Size 8.1.14. DetNet Network Size
DetNet networks range in size from very small, e.g. inside a single DetNet networks range in size from very small, e.g., inside a single
industrial machine, to very large, for example a Utility Grid network industrial machine, to very large, e.g., a Utility Grid network
spanning a whole country. spanning a whole country.
The size of the network might be related to how the attack is The size of the network might be related to how the attack is
introduced into the network, for example if the entire network is introduced into the network. For example, if the entire network is
local, there is a threat that power can be cut to the entire network. local, there is a threat that power can be cut to the entire network.
If the network is large, perhaps only a part of the network is If the network is large, perhaps only a part of the network is
attacked. attacked.
A Delay attack might be as relevant to a small network as to a large A Delay attack might be as relevant to a small network as to a large
network, although the amount of delay might be different. network, although the amount of delay might be different.
Attacks sourced from IT traffic might be more likely in large Attacks sourced from IT traffic might be more likely in large
networks, since more people might have access to the network, networks since more people might have access to the network,
presenting a larger attack surface. Similarly Path Manipulation, presenting a larger attack surface. Similarly, Path Manipulation,
Path Choice and Time Synchronization attacks seem more likely Path Choice, and Time-Synchronization attacks seem more likely
relevant to large networks. relevant to large networks.
8.1.15. Multiple Hops 8.1.15. Multiple Hops
Large DetNet networks (e.g. a Utility Grid network) may involve many Large DetNet networks (e.g., a Utility Grid network) may involve many
"hops" over various kinds of links for example radio repeaters, "hops" over various kinds of links, for example, radio repeaters,
microwave links, fiber optic links, etc. microwave links, fiber optic links, etc.
An attacker who has knowledge of the operation of a component or An attacker who has knowledge of the operation of a component or
device's internal software (such as "device drivers") may be able to device's internal software (such as "device drivers") may be able to
take advantage of this knowledge to design an attack that could take advantage of this knowledge to design an attack that could
exploit flaws (or even the specifics of normal operation) in the exploit flaws (or even the specifics of normal operation) in the
communication between the various links. communication between the various links.
It is also possible that a large scale DetNet topology containing It is also possible that a large-scale DetNet topology containing
various kinds of links may not be in as common use as other more various kinds of links may not be in as common use as other more
homogeneous topologies. This situation may present more opportunity homogeneous topologies. This situation may present more opportunity
for attackers to exploit software and/or protocol flaws in or between for attackers to exploit software and/or protocol flaws in or between
these components, because these components or configurations may not these components because these components or configurations may not
have been sufficiently tested for interoperability (in the way they have been sufficiently tested for interoperability (in the way they
would be as a result of broad usage). This may be of particular would be as a result of broad usage). This may be of particular
concern to early adopters of new DetNet components or technologies. concern to early adopters of new DetNet components or technologies.
Of the attacks we have defined, the ones identified in Section 8.1.14 Of the attacks we have defined, the ones identified in Section 8.1.14
as germane to large networks are the most relevant. as germane to large networks are the most relevant.
8.1.16. Level of Service 8.1.16. Level of Service
A DetNet is expected to provide means to configure the network that A DetNet is expected to provide means to configure the network that
include querying network path latency, requesting bounded latency for include querying network path latency, requesting bounded latency for
a given DetNet flow, requesting worst case maximum and/or minimum a given DetNet flow, requesting worst-case maximum and/or minimum
latency for a given path or DetNet flow, and so on. It is an latency for a given path or DetNet flow, and so on. It is an
expected case that the network cannot provide a given requested expected case that the network cannot provide a given requested
service level. In such cases the network control system should reply service level. In such cases, the network control system should
that the requested service level is not available (as opposed to reply that the requested service level is not available (as opposed
accepting the parameter but then not delivering the desired to accepting the parameter but then not delivering the desired
behavior). behavior).
Controller plane attacks such as Signaling Packet Modification and Controller plane attacks such as Signaling Packet Modification and
Injection could be used to modify or create control traffic that Injection could be used to modify or create control traffic that
could interfere with the process of a user requesting a level of could interfere with the process of a user requesting a level of
service and/or the reply from the network. service and/or the reply from the network.
Reconnaissance could be used to characterize flows and perhaps target Reconnaissance could be used to characterize flows and perhaps target
specific flows for attack via the controller plane as noted in specific flows for attack via the controller plane as noted in
Section 6.7. Section 6.7.
8.1.17. Bounded Latency 8.1.17. Bounded Latency
DetNet provides the expectation of guaranteed bounded latency. DetNet provides the expectation of guaranteed bounded latency.
Delay attacks can cause packets to miss their agreed-upon latency Delay attacks can cause packets to miss their agreed-upon latency
boundaries. boundaries.
Time Synchronization attacks can corrupt the time reference of the Time-Synchronization attacks can corrupt the time reference of the
system, resulting in missed latency deadlines (with respect to the system, resulting in missed latency deadlines (with respect to the
"correct" time reference). "correct" time reference).
8.1.18. Low Latency 8.1.18. Low Latency
Applications may require "extremely low latency" however depending on Applications may require "extremely low latency"; however, depending
the application these may mean very different latency values; for on the application, these may mean very different latency values.
example "low latency" across a Utility grid network is on a different For example, "low latency" across a Utility Grid network is on a
time scale than "low latency" in a motor control loop in a small different time scale than "low latency" in a motor control loop in a
machine. The intent is that the mechanisms for specifying desired small machine. The intent is that the mechanisms for specifying
latency include wide ranges, and that architecturally there is desired latency include wide ranges, and that architecturally there
nothing to prevent arbitrarily low latencies from being implemented is nothing to prevent arbitrarily low latencies from being
in a given network. implemented in a given network.
Attacks on the controller plane (as described in the Level of Service Attacks on the controller plane (as described in the Level of Service
theme Section 8.1.16) and Delay and Time attacks (as described in the theme; see Section 8.1.16) and Delay and Time attacks (as described
Bounded Latency theme Section 8.1.17) both apply here. in the Bounded Latency theme; see Section 8.1.17) both apply here.
8.1.19. Bounded Jitter (Latency Variation) 8.1.19. Bounded Jitter (Latency Variation)
DetNet is expected to provide bounded jitter (packet to packet DetNet is expected to provide bounded jitter (packet-to-packet
latency variation). latency variation).
Delay attacks can cause packets to vary in their arrival times, Delay attacks can cause packets to vary in their arrival times,
resulting in packet to packet latency variation, thereby violating resulting in packet-to-packet latency variation, thereby violating
the jitter specification. the jitter specification.
8.1.20. Symmetrical Path Delays 8.1.20. Symmetrical Path Delays
Some applications would like to specify that the transit delay time Some applications would like to specify that the transit delay time
values be equal for both the transmit and return paths. values be equal for both the transmit and return paths.
Delay attacks can cause path delays to materially differ between Delay attacks can cause path delays to materially differ between
paths. paths.
Time Synchronization attacks can corrupt the time reference of the Time-Synchronization attacks can corrupt the time reference of the
system, resulting in path delays that may be perceived to be system, resulting in path delays that may be perceived to be
different (with respect to the "correct" time reference) even if they different (with respect to the "correct" time reference) even if they
are not materially different. are not materially different.
8.1.21. Reliability and Availability 8.1.21. Reliability and Availability
DetNet based systems are expected to be implemented with essentially DetNet-based systems are expected to be implemented with essentially
arbitrarily high availability (for example 99.9999% up time, or even arbitrarily high availability (for example, 99.9999% up time, or even
12 nines). The intent is that the DetNet designs should not make any 12 nines). The intent is that the DetNet designs should not make any
assumptions about the level of reliability and availability that may assumptions about the level of reliability and availability that may
be required of a given system, and should define parameters for be required of a given system and should define parameters for
communicating these kinds of metrics within the network. communicating these kinds of metrics within the network.
Any attack on the system, of any type, can affect its overall Any attack on the system, of any type, can affect its overall
reliability and availability, thus in the mapping table Figure 4 we reliability and availability; thus, in the mapping table (Table 5),
have marked every attack. Since every DetNet depends to a greater or we have marked every attack. Since every DetNet depends to a greater
lesser degree on reliability and availability, this essentially means or lesser degree on reliability and availability, this essentially
that all networks have to mitigate all attacks, which to a greater or means that all networks have to mitigate all attacks, which to a
lesser degree defeats the purpose of associating attacks with use greater or lesser degree defeats the purpose of associating attacks
cases. It also underscores the difficulty of designing "extremely with use cases. It also underscores the difficulty of designing
high reliability" networks. "extremely high reliability" networks.
In practice, network designers can adopt a risk-based approach, in In practice, network designers can adopt a risk-based approach in
which only those attacks are mitigated whose potential cost is higher which only those attacks are mitigated whose potential cost is higher
than the cost of mitigation. than the cost of mitigation.
8.1.22. Redundant Paths 8.1.22. Redundant Paths
This document expects that each DetNet system will be implemented to This document expects that each DetNet system will be implemented to
some essentially arbitrary level of reliability and/or availability, some essentially arbitrary level of reliability and/or availability,
depending on the use case. A strategy used by DetNet for providing depending on the use case. A strategy used by DetNet for providing
extraordinarily high levels of reliability when justified is to extraordinarily high levels of reliability when justified is to
provide redundant paths between which traffic can be seamlessly provide redundant paths between which traffic can be seamlessly
switched, all the while maintaining the required performance of that switched, all the while maintaining the required performance of that
system. system.
Replication-related attacks are by definition applicable here. Replication-related attacks are by definition applicable here.
Controller plane attacks can also interfere with the configuration of Controller plane attacks can also interfere with the configuration of
redundant paths. redundant paths.
8.1.23. Security Measures 8.1.23. Security Measures
If any of the security mechanisms which protect the DetNet are If any of the security mechanisms that protect the DetNet are
attacked or subverted, this can result in malfunction of the network. attacked or subverted, this can result in malfunction of the network.
Thus the security systems themselves needs to be robust against Thus, the security systems themselves need to be robust against
attacks. attacks.
The general topic of protection of security mechanisms is not unique The general topic of protection of security mechanisms is not unique
to DetNet; it is identical to the case of securing any security to DetNet; it is identical to the case of securing any security
mechanism for any network. This document addresses these concerns mechanism for any network. This document addresses these concerns
only to the extent that they are unique to DetNet. only to the extent that they are unique to DetNet.
8.2. Summary of Attack Types per Use Case Common Theme 8.2. Summary of Attack Types per Use Case Common Theme
The List of Attacks table Figure 4 lists the attacks of Section 5, The List of Attacks table (Table 4) lists the attacks described in
Security Threats, assigning a number to each type of attack. That Section 5, Security Threats, assigning a number to each type of
number is then used as a short form identifier for the attack in attack. That number is then used as a short form identifier for the
Figure 5, Mapping Between Themes and Attacks. attack in Table 5, Mapping between Themes and Attacks.
+----+-------------------------------------------+ +====+============================================+
| | Attack | | | Attack |
+----+-------------------------------------------+ +====+============================================+
| 1 |Delay Attack | | 1 | Delay Attack |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 2 |DetNet Flow Modification or Spoofing | | 2 | DetNet Flow Modification or Spoofing |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 3 |Inter-Segment Attack | | 3 | Inter-segment Attack |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 4 |Replication: Increased attack surface | | 4 | Replication: Increased Attack Surface |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 5 |Replication-related Header Manipulation | | 5 | Replication-Related Header Manipulation |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 6 |Path Manipulation | | 6 | Path Manipulation |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 7 |Path Choice: Increased Attack Surface | | 7 | Path Choice: Increased Attack Surface |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 8 |Control or Signaling Packet Modification | | 8 | Control or Signaling Packet Modification |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 9 |Control or Signaling Packet Injection | | 9 | Control or Signaling Packet Injection |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 10 |Reconnaissance | | 10 | Reconnaissance |
+----+-------------------------------------------+ +----+--------------------------------------------+
| 11 |Attacks on Time Synchronization Mechanisms | | 11 | Attacks on Time-Synchronization Mechanisms |
+----+-------------------------------------------+ +----+--------------------------------------------+
Figure 4: List of Attacks Table 4: List of Attacks
The Mapping Between Themes and Attacks table Figure 5 maps the use The Mapping between Themes and Attacks table (Table 5) maps the use
case themes of [RFC8578] (as also enumerated in this document) to the case themes of [RFC8578] (as also enumerated in this document) to the
attacks of Figure 4. Each row specifies a theme, and the attacks attacks of Table 4. Each row specifies a theme, and the attacks
relevant to this theme are marked with a '+'. The row items which relevant to this theme are marked with a "+". The row items that
have no threats associated with them are included in the table for have no threats associated with them are included in the table for
completeness of the list of Use Case Common Themes, and do not have completeness of the list of Use Case Common Themes and do not have
DetNet-specific threats associated with them. DetNet-specific threats associated with them.
+----------------------------+--------------------------------+ +====================+=============================================+
| Theme | Attack | | Theme | Attack |
| +--+--+--+--+--+--+--+--+--+--+--+ | +===+===+===+===+===+===+===+===+===+====+====+
| | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11| | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +====================+===+===+===+===+===+===+===+===+===+====+====+
|Network Layer - AVB/TSN Eth.| +| +| +| +| +| +| +| +| +| +| +| | Network Layer - | + | + | + | + | + | + | + | + | + | + | + |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | AVB/TSN Eth. | | | | | | | | | | | |
|Central Administration | | | | | | +| +| +| +| +| +| +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Central | | | | | | + | + | + | + | + | + |
|Hot Swap | | +| +| | | | | | | | +| | Administration | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|Data Flow Information Models| | | | | | | | | | | | | Hot Swap | | + | + | | | | | | | | + |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|L2 and L3 Integration | | | | | | | | | | | | | Data Flow | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Information Models | | | | | | | | | | | |
|End-to-end Delivery | +| +| +| +| +| +| +| +| +| | +| +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | L2 and L3 | | | | | | | | | | | |
|Proprietary Deterministic | | | +| | | +| +| +| +| | | | Integration | | | | | | | | | | | |
|Ethernet Networks | | | | | | | | | | | | +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | End-to-End | + | + | + | + | + | + | + | + | | + | |
|Replacement for Proprietary | | | +| | | +| +| +| +| | | | Delivery | | | | | | | | | | | |
|Fieldbuses | | | | | | | | | | | | +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Proprietary | | | + | | | + | + | + | + | | |
|Deterministic vs. Best- | | | +| | | | | | | | | | Deterministic | | | | | | | | | | | |
|Effort Traffic | | | | | | | | | | | | | Ethernet Networks | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|Deterministic Flows | +| +| +| | +| +| | +| | | | | Replacement for | | | + | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Proprietary | | | | | | | | | | | |
|Unused Reserved Bandwidth | | +| +| | | | | +| +| | | | Fieldbuses | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|Interoperability | | | | | | | | | | | | | Deterministic vs. | + | + | + | | + | + | | + | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Best-Effort | | | | | | | | | | | |
|Cost Reductions | | | | | | | | | | | | | Traffic | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|Insufficiently Secure | | | | | | | | | | | | | Deterministic | + | + | + | | + | + | | + | | | |
|Components | | | | | | | | | | | | | Flows | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|DetNet Network Size | +| | | | | +| +| | | | +| | Unused Reserved | | + | + | | | | | + | + | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Bandwidth | | | | | | | | | | | |
|Multiple Hops | +| +| | | | +| +| | | | +| +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Interoperability | | | | | | | | | | | |
|Level of Service | | | | | | | | +| +| +| | +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Cost Reductions | | | | | | | | | | | |
|Bounded Latency | +| | | | | | | | | | +| +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Insufficiently | | | | | | | | | | | |
|Low Latency | +| | | | | | | +| +| | +| | Secure Components | | | | | | | | | | | |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ +--------------------+---+---+---+---+---+---+---+---+---+----+----+
|Bounded Jitter | +| | | | | | | | | | | | DetNet Network | + | | | | | + | + | | | | + |
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Size | | | | | | | | | | | |
|Symmetric Path Delays | +| | | | | | | | | | +| +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Multiple Hops | + | + | | | | + | + | | | | + |
|Reliability and Availability| +| +| +| +| +| +| +| +| +| +| +| +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Level of Service | | | | | | | | + | + | + | |
|Redundant Paths | | | | +| +| | | +| +| | | +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Bounded Latency | + | | | | | | | | | | + |
|Security Measures | | | | | | | | | | | | +--------------------+---+---+---+---+---+---+---+---+---+----+----+
+----------------------------+--+--+--+--+--+--+--+--+--+--+--+ | Low Latency | + | | | | | | | + | + | | + |
+--------------------+---+---+---+---+---+---+---+---+---+----+----+
| Bounded Jitter | + | | | | | | | | | | |
+--------------------+---+---+---+---+---+---+---+---+---+----+----+
| Symmetric Path | + | | | | | | | | | | + |
| Delays | | | | | | | | | | | |
+--------------------+---+---+---+---+---+---+---+---+---+----+----+
| Reliability and | + | + | + | + | + | + | + | + | + | + | + |
| Availability | | | | | | | | | | | |
+--------------------+---+---+---+---+---+---+---+---+---+----+----+
| Redundant Paths | | | | + | + | | | + | + | | |
+--------------------+---+---+---+---+---+---+---+---+---+----+----+
| Security Measures | | | | | | | | | | | |
+--------------------+---+---+---+---+---+---+---+---+---+----+----+
Figure 5: Mapping Between Themes and Attacks Table 5: Mapping between Themes and Attacks
9. Security Considerations for OAM Traffic 9. Security Considerations for OAM Traffic
This section considers DetNet-specific security considerations for This section considers DetNet-specific security considerations for
packet traffic that is generated and transmitted over a DetNet as packet traffic that is generated and transmitted over a DetNet as
part of OAM (Operations, Administration, and Maintenance). For the part of OAM (Operations, Administration, and Maintenance). For the
purposes of this discussion, OAM traffic falls into one of two basic purposes of this discussion, OAM traffic falls into one of two basic
types: types:
o OAM traffic generated by the network itself. The additional * OAM traffic generated by the network itself. The additional
bandwidth required for such packets is added by the network bandwidth required for such packets is added by the network
administration, presumably transparent to the customer. Security administration, presumably transparent to the customer. Security
considerations for such traffic are not DetNet-specific (apart considerations for such traffic are not DetNet specific (apart
from such traffic being subject to the same DetNet-specific from such traffic being subject to the same DetNet-specific
security considerations as any other DetNet data flow) and are security considerations as any other DetNet data flow) and are
thus not covered in this document. thus not covered in this document.
o OAM traffic generated by the customer. From a DetNet security * OAM traffic generated by the customer. From a DetNet security
point of view, DetNet security considerations for such traffic are point of view, DetNet security considerations for such traffic are
exactly the same as for any other customer data flows. exactly the same as for any other customer data flows.
From the perspective of an attack, OAM traffic is indistinguishable From the perspective of an attack, OAM traffic is indistinguishable
from DetNet traffic and the network needs to be secure against from DetNet traffic, and the network needs to be secure against
injection, removal, or modification of traffic of any kind, including injection, removal, or modification of traffic of any kind, including
OAM traffic. A DetNet is sensitive to any form of packet injection, OAM traffic. A DetNet is sensitive to any form of packet injection,
removal or manipulation and in this respect DetNet OAM traffic is no removal, or manipulation, and in this respect DetNet OAM traffic is
different. Techniques for securing a DetNet against these threats no different. Techniques for securing a DetNet against these threats
have been discussed elsewhere in this document. have been discussed elsewhere in this document.
10. DetNet Technology-Specific Threats 10. DetNet Technology-Specific Threats
Section 5, Security Threats, described threats which are independent Section 5, Security Threats, describes threats that are independent
of a DetNet implementation. This section considers threats of a DetNet implementation. This section considers threats
specifically related to the IP- and MPLS-specific aspects of DetNet specifically related to the IP- and MPLS-specific aspects of DetNet
implementations. implementations.
The primary security considerations for the data plane specifically The primary security considerations for the data plane specifically
are to maintain the integrity of the data and the delivery of the are to maintain the integrity of the data and the delivery of the
associated DetNet service traversing the DetNet network. associated DetNet service traversing the DetNet network.
The primary relevant differences between IP and MPLS implementations The primary relevant differences between IP and MPLS implementations
are in flow identification and OAM methodologies. are in flow identification and OAM methodologies.
As noted in [RFC8655], DetNet operates at the IP layer ( [RFC8939]) As noted in [RFC8655], DetNet operates at the IP layer [RFC8939] and
and delivers service over sub-layer technologies such as MPLS delivers service over sub-layer technologies such as MPLS [RFC8964]
([RFC8964]) and IEEE 802.1 Time-Sensitive Networking (TSN) and IEEE 802.1 Time-Sensitive Networking (TSN) [RFC9023].
([I-D.ietf-detnet-ip-over-tsn]). Application flows can be protected Application flows can be protected through whatever means are
through whatever means are provided by the layer and sub-layer provided by the layer and sub-layer technologies. For example,
technologies. For example, technology-specific encryption may be technology-specific encryption may be used for IP flows (IPsec
used, for example for IP flows, IPSec [RFC4301]. For IP over [RFC4301]). For IP-over-Ethernet (Layer 2) flows using an underlying
Ethernet (Layer 2) flows using an underlying sub-net, MACSec sub-net, MACsec [IEEE802.1AE-2018] may be appropriate. For some use
[IEEE802.1AE-2018] may be appropriate. For some use cases packet cases, packet integrity protection without encryption may be
integrity protection without encryption may be sufficient. sufficient.
However, if the DetNet nodes cannot decrypt IPsec traffic, then However, if the DetNet nodes cannot decrypt IPsec traffic, then
DetNet flow identification for encrypted IP traffic flows must be DetNet flow identification for encrypted IP traffic flows must be
performed in a different way than it would be for unencrypted IP performed in a different way than it would be for unencrypted IP
DetNet flows. The DetNet IP Data Plane identifies unencrypted flows DetNet flows. The DetNet IP data plane identifies unencrypted flows
via a 6-tuple that consists of two IP addresses, the transport via a 6-tuple that consists of two IP addresses, the transport
protocol ID, two transport protocol port numbers and the DSCP in the protocol ID, two transport protocol port numbers, and the DSCP in the
IP header. When IPsec is used, the transport header is encrypted and IP header. When IPsec is used, the transport header is encrypted and
the next protocol ID is an IPsec protocol, usually ESP, and not a the next protocol ID is an IPsec protocol, usually Encapsulating
transport protocol, leaving only three components of the 6-tuple, Security Payload (ESP), and not a transport protocol, leaving only
which are the two IP addresses and the DSCP. If the IPsec sessions three components of the 6-tuple, which are the two IP addresses and
are established by a controller, then this controller could also the DSCP. If the IPsec sessions are established by a controller,
transmit (in the clear) the Security Parameter Index (SPI) and thus then this controller could also transmit (in the clear) the Security
the SPI could be used (in addition to the pair of IP addresses) for Parameter Index (SPI) and thus the SPI could be used (in addition to
flow identification. Identification of DetNet flows over IPsec is the pair of IP addresses) for flow identification. Identification of
further discussed in Section 5.1.2.3. of [RFC8939]. DetNet flows over IPsec is further discussed in Section 5.1.2.3 of
[RFC8939].
Sections below discuss threats specific to IP and MPLS in more Sections below discuss threats specific to IP and MPLS in more
detail. detail.
10.1. IP 10.1. IP
The IP protocol has a long history of security considerations and IP has a long history of security considerations and architectural
architectural protection mechanisms. From a data plane perspective protection mechanisms. From a data plane perspective, DetNet does
DetNet does not add or modify any IP header information, so the not add or modify any IP header information, so the carriage of
carriage of DetNet traffic over an IP data plane does not introduce DetNet traffic over an IP data plane does not introduce any new
any new security issues that were not there before, apart from those security issues that were not there before, apart from those already
already described in the data-plane-independent threats section described in the data-plane-independent threats section (Section 5).
Section 5, Security Threats.
Thus the security considerations for a DetNet based on an IP data Thus, the security considerations for a DetNet based on an IP data
plane are purely inherited from the rich IP Security literature and plane are purely inherited from the rich IP security literature and
code/application base, and the data-plane-independent section of this code/application base, and the data-plane-independent section of this
document. document.
Maintaining security for IP segments of a DetNet may be more Maintaining security for IP segments of a DetNet may be more
challenging than for the MPLS segments of the network, given that the challenging than for the MPLS segments of the network given that the
IP segments of the network may reach the edges of the network, which IP segments of the network may reach the edges of the network, which
are more likely to involve interaction with potentially malevolent are more likely to involve interaction with potentially malevolent
outside actors. Conversely MPLS is inherently more secure than IP outside actors. Conversely, MPLS is inherently more secure than IP
since it is internal to routers and it is well-known how to protect since it is internal to routers and it is well known how to protect
it from outside influence. it from outside influence.
Another way to look at DetNet IP security is to consider it in the Another way to look at DetNet IP security is to consider it in the
light of VPN security; as an industry we have a lot of experience light of VPN security. As an industry, we have a lot of experience
with VPNs running through networks with other VPNs, it is well known with VPNs running through networks with other VPNs -- it is well
how to secure the network for that. However for a DetNet we have the known how to secure the network for that. However, for a DetNet, we
additional subtlety that any possible interaction of one packet with have the additional subtlety that any possible interaction of one
another can have a potentially deleterious effect on the time packet with another can have a potentially deleterious effect on the
properties of the flows. So the network must provide sufficient time properties of the flows. So the network must provide sufficient
isolation between flows, for example by protecting the forwarding isolation between flows, for example, by protecting the forwarding
bandwidth and related resources so that they are available to detnet bandwidth and related resources so that they are available to DetNet
traffic, by whatever means are appropriate for the data plane of that traffic, by whatever means are appropriate for the data plane of that
network, for example through the use of queueing mechanisms. network, for example, through the use of queuing mechanisms.
In a VPN, bandwidth is generally guaranteed over a period of time, In a VPN, bandwidth is generally guaranteed over a period of time
whereas in DetNet it is not aggregated over time. This implies that whereas in DetNet, it is not aggregated over time. This implies that
any VPN-type protection mechanism must also maintain the DetNet any VPN-type protection mechanism must also maintain the DetNet
timing constraints. timing constraints.
10.2. MPLS 10.2. MPLS
An MPLS network carrying DetNet traffic is expected to be a "well- An MPLS network carrying DetNet traffic is expected to be a "well-
managed" network. Given that this is the case, it is difficult for managed" network. Given that this is the case, it is difficult for
an attacker to pass a raw MPLS encoded packet into a network because an attacker to pass a raw MPLS-encoded packet into a network because
operators have considerable experience at excluding such packets at operators have considerable experience at excluding such packets at
the network boundaries, as well as excluding MPLS packets being the network boundaries as well as excluding MPLS packets being
inserted through the use of a tunnel. inserted through the use of a tunnel.
MPLS security is discussed extensively in [RFC5920] ("Security MPLS security is discussed extensively in [RFC5920] ("Security
Framework for MPLS and GMPLS Networks") to which the reader is Framework for MPLS and GMPLS Networks") to which the reader is
referred. referred.
[RFC6941] builds on [RFC5920] by providing additional security [RFC6941] builds on [RFC5920] by providing additional security
considerations that are applicable to the MPLS-TP extensions considerations that are applicable to the MPLS-TP extensions
appropriate to the MPLS Transport Profile [RFC5921], and thus to the appropriate to the MPLS Transport Profile [RFC5921] and thus to the
operation of DetNet over some types of MPLS network. operation of DetNet over some types of MPLS network.
[RFC5921] introduces to MPLS new Operations, Administration, and [RFC5921] introduces to MPLS new Operations, Administration, and
Maintenance (OAM) capabilities, a transport-oriented path protection Maintenance (OAM) capabilities; a transport-oriented path protection
mechanism, and strong emphasis on static provisioning supported by mechanism; and strong emphasis on static provisioning supported by
network management systems. network management systems.
The operation of DetNet over an MPLS network builds on MPLS and The operation of DetNet over an MPLS network builds on MPLS and
pseudowire encapsulation. Thus for guidance on securing the DetNet pseudowire encapsulation. Thus, for guidance on securing the DetNet
elements of DetNet over MPLS the reader is also referred to the elements of DetNet over MPLS, the reader is also referred to the
security considerations of [RFC4385], [RFC5586], [RFC3985], security considerations of [RFC4385], [RFC5586], [RFC3985],
[RFC6073], and [RFC6478]. [RFC6073], and [RFC6478].
Having attended to the conventional aspects of network security it is Having attended to the conventional aspects of network security, it
necessary to attend to the dynamic aspects. The closest experience is necessary to attend to the dynamic aspects. The closest
that the IETF has with securing protocols that are sensitive to experience that the IETF has with securing protocols that are
manipulation of delay are the two way time transfer protocols (TWTT), sensitive to manipulation of delay are the two-way time transfer
which are NTP [RFC5905] and Precision Time Protocol [IEEE1588]. The (TWTT) protocols, which are NTP [RFC5905] and the Precision Time
security requirements for these are described in [RFC7384]. Protocol [IEEE1588]. The security requirements for these are
described in [RFC7384].
One particular problem that has been observed in operational tests of One particular problem that has been observed in operational tests of
TWTT protocols is the ability for two closely but not completely TWTT protocols is the ability for two closely but not completely
synchronized flows to beat and cause a sudden phase hit to one of the synchronized flows to beat and cause a sudden phase hit to one of the
flows. This can be mitigated by the careful use of a scheduling flows. This can be mitigated by the careful use of a scheduling
system in the underlying packet transport. system in the underlying packet transport.
Some investigations into protection of MPLS systems against dynamic Some investigations into protection of MPLS systems against dynamic
attacks exist, such as [I-D.ietf-mpls-opportunistic-encrypt]; perhaps attacks exist, such as [MPLS-OPP-ENCRYPT]; perhaps deployment of
deployment of DetNets will encourage additional such investigations. DetNets will encourage additional such investigations.
11. IANA Considerations 11. IANA Considerations
This document includes no requests from IANA. This document has no IANA actions.
12. Security Considerations 12. Security Considerations
The security considerations of DetNet networks are presented The security considerations of DetNet networks are presented
throughout this document. throughout this document.
13. Privacy Considerations 13. Privacy Considerations
Privacy in the context of DetNet is maintained by the base Privacy in the context of DetNet is maintained by the base
technologies specific to the DetNet and user traffic. For example technologies specific to the DetNet and user traffic. For example,
TSN can use MACsec, IP can use IPsec, applications can use IP TSN can use MACsec, IP can use IPsec, and applications can use IP
transport protocol-provided methods e.g. TLS and DTLS. MPLS transport protocol-provided methods, e.g., TLS and DTLS. MPLS
typically uses L2/L3 VPNs combined with the previously mentioned typically uses L2/L3 VPNs combined with the previously mentioned
privacy methods. privacy methods.
However, note that reconnaissance threats such as traffic analysis However, note that reconnaissance threats such as traffic analysis
and monitoring of electrical side channels can still cause there to and monitoring of electrical side channels can still cause there to
be privacy considerations even when traffic is encrypted. be privacy considerations even when traffic is encrypted.
14. Contributors 14. References
The Editor would like to recognize the contributions of the following
individuals to this draft.
Subir Das (Applied Communication Sciences)
150 Mount Airy Road, Basking Ridge, New Jersey, 07920, USA
email sdas@appcomsci.com
John Dowdell (Airbus Defence and Space)
Celtic Springs, Newport, NP10 8FZ, United Kingdom
email john.dowdell.ietf@gmail.com
Henrik Austad (SINTEF Digital)
Klaebuveien 153, Trondheim, 7037, Norway
email henrik@austad.us
Norman Finn (Huawei)
3101 Rio Way, Spring Valley, California 91977, USA
email nfinn@nfinnconsulting.com
Stewart Bryant (Futurewei Technologies)
email: stewart.bryant@gmail.com
David Black (Dell EMC)
176 South Street, Hopkinton, MA 01748, USA
email: david.black@dell.com
Carsten Bormann (Universitat Bremen TZI)
Postfach 330440, D-28359 Bremen, Germany
email: cabo@tzi.org
15. References
15.1. Normative References 14.1. Normative References
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655, "Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019, DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>. <https://www.rfc-editor.org/info/rfc8655>.
[RFC8938] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S. [RFC8938] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane Bryant, "Deterministic Networking (DetNet) Data Plane
Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020, Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
<https://www.rfc-editor.org/info/rfc8938>. <https://www.rfc-editor.org/info/rfc8938>.
skipping to change at page 54, line 20 skipping to change at line 2511
[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S. [RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane: Bryant, "Deterministic Networking (DetNet) Data Plane:
IP", RFC 8939, DOI 10.17487/RFC8939, November 2020, IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
<https://www.rfc-editor.org/info/rfc8939>. <https://www.rfc-editor.org/info/rfc8939>.
[RFC8964] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant, [RFC8964] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant,
S., and J. Korhonen, "Deterministic Networking (DetNet) S., and J. Korhonen, "Deterministic Networking (DetNet)
Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January
2021, <https://www.rfc-editor.org/info/rfc8964>. 2021, <https://www.rfc-editor.org/info/rfc8964>.
15.2. Informative References 14.2. Informative References
[ARINC664P7] [ARINC664P7]
ARINC, "ARINC 664 Aircraft Data Network, Part 7, Avionics ARINC, "Aircraft Data Network Part 7 Avionics Full-Duplex
Full-Duplex Switched Ethernet Network", 2009. Switched Ethernet Network", ARINC 664 P7, September 2009.
[I-D.ietf-detnet-flow-information-model] [BCP107] Bellovin, S. and R. Housley, "Guidelines for Cryptographic
Varga, B., Farkas, J., Cummings, R., Jiang, Y., and D. Key Management", BCP 107, RFC 4107, June 2005.
Fedyk, "DetNet Flow and Service Information Model", draft-
ietf-detnet-flow-information-model-14 (work in progress),
January 2021.
[I-D.ietf-detnet-ip-oam] <https://www.rfc-editor.org/info/bcp107>
Mirsky, G., Chen, M., and D. Black, "Operations,
Administration and Maintenance (OAM) for Deterministic
Networks (DetNet) with IP Data Plane", draft-ietf-detnet-
ip-oam-01 (work in progress), January 2021.
[I-D.ietf-detnet-ip-over-mpls] [BCP72] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Varga, B., Berger, L., Fedyk, D., Bryant, S., and J. Text on Security Considerations", BCP 72, RFC 3552, July
Korhonen, "DetNet Data Plane: IP over MPLS", draft-ietf- 2003.
detnet-ip-over-mpls-09 (work in progress), October 2020.
[I-D.ietf-detnet-ip-over-tsn] <https://www.rfc-editor.org/info/bcp72>
Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet
Data Plane: IP over IEEE 802.1 Time Sensitive Networking
(TSN)", draft-ietf-detnet-ip-over-tsn-05 (work in
progress), December 2020.
[I-D.ietf-detnet-mpls-oam] [DETNET-IP-OAM]
Mirsky, G., Chen, M., and D. Black, "Operations,
Administration and Maintenance (OAM) for Deterministic
Networks (DetNet) with IP Data Plane", Work in Progress,
Internet-Draft, draft-ietf-detnet-ip-oam-02, 30 March
2021, <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-ip-oam-02>.
[DETNET-MPLS-OAM]
Mirsky, G. and M. Chen, "Operations, Administration and Mirsky, G. and M. Chen, "Operations, Administration and
Maintenance (OAM) for Deterministic Networks (DetNet) with Maintenance (OAM) for Deterministic Networks (DetNet) with
MPLS Data Plane", draft-ietf-detnet-mpls-oam-02 (work in MPLS Data Plane", Work in Progress, Internet-Draft, draft-
progress), January 2021. ietf-detnet-mpls-oam-03, 30 March 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
mpls-oam-03>.
[I-D.ietf-detnet-mpls-over-udp-ip] [DETNET-SERVICE-MODEL]
Varga, B., Farkas, J., Berger, L., Malis, A., and S. Varga, B., Ed. and J. Farkas, "DetNet Service Model", Work
Bryant, "DetNet Data Plane: MPLS over UDP/IP", draft-ietf- in Progress, Internet-Draft, draft-varga-detnet-service-
detnet-mpls-over-udp-ip-08 (work in progress), December model-02, May 2017,
2020. <https://datatracker.ietf.org/doc/html/draft-varga-detnet-
service-model-02>.
[I-D.ietf-detnet-yang] [DETNET-YANG]
Geng, X., Chen, M., Ryoo, Y., Fedyk, D., Rahman, R., and Geng, X., Chen, M., Ryoo, Y., Fedyk, D., Rahman, R., and
Z. Li, "Deterministic Networking (DetNet) Configuration Z. Li, "Deterministic Networking (DetNet) YANG Model",
YANG Model", draft-ietf-detnet-yang-09 (work in progress), Work in Progress, Internet-Draft, draft-ietf-detnet-yang-
November 2020. 12, 19 May 2021, <https://datatracker.ietf.org/doc/html/
draft-ietf-detnet-yang-12>.
[I-D.ietf-ipsecme-g-ikev2]
Smyslov, V. and B. Weis, "Group Key Management using
IKEv2", draft-ietf-ipsecme-g-ikev2-02 (work in progress),
January 2021.
[I-D.ietf-mpls-opportunistic-encrypt]
Farrel, A. and S. Farrell, "Opportunistic Security in MPLS
Networks", draft-ietf-mpls-opportunistic-encrypt-03 (work
in progress), March 2017.
[I-D.varga-detnet-service-model]
Varga, B. and J. Farkas, "DetNet Service Model", draft-
varga-detnet-service-model-02 (work in progress), May
2017.
[IEEE1588] [IEEE1588] IEEE, "IEEE 1588 Standard for a Precision Clock
IEEE, "IEEE 1588 Standard for a Precision Clock
Synchronization Protocol for Networked Measurement and Synchronization Protocol for Networked Measurement and
Control Systems Version 2", 2008. Control Systems", IEEE Std. 1588-2008,
DOI 10.1109/IEEESTD.2008.4579760, July 2008,
<https://doi.org/10.1109/IEEESTD.2008.4579760>.
[IEEE802.1AE-2018] [IEEE802.1AE-2018]
IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC IEEE, "IEEE Standard for Local and metropolitan area
Security (MACsec)", 2018, networks-Media Access Control (MAC) Security", IEEE Std.
<https://ieeexplore.ieee.org/document/8585421>. 802.1AE-2018, DOI 10.1109/IEEESTD.2018.8585421, December
2018, <https://ieeexplore.ieee.org/document/8585421>.
[IEEE802.1BA] [IEEE802.1BA]
IEEE Standards Association, "IEEE Standard for Local and IEEE, "IEEE Standard for Local and metropolitan area
Metropolitan Area Networks -- Audio Video Bridging (AVB) networks--Audio Video Bridging (AVB) Systems", IEEE Std.
Systems", 2011, 802.1BA-2011, DOI 10.1109/IEEESTD.2011.6032690, September
<https://ieeexplore.ieee.org/document/6032690>. 2011, <https://ieeexplore.ieee.org/document/6032690>.
[IEEE802.1Q] [IEEE802.1Q]
IEEE Standards Association, "IEEE Standard for Local and IEEE, "IEEE Standard for Local and metropolitan area
metropolitan area networks--Bridges and Bridged Networks - networks--Bridges and Bridged Networks", IEEE Std. 802.1Q-
Annex J - Connectivity Fault Management", 2014, 2014, DOI 10.1109/IEEESTD.2014.6991462, December 2014,
<https://ieeexplore.ieee.org/document/6991462>. <https://ieeexplore.ieee.org/document/6991462>.
[IEEE802.1Qbv-2015] [IEEE802.1Qbv-2015]
IEEE Standards Association, "IEEE Standard for Local and IEEE, "IEEE Standard for Local and metropolitan area
metropolitan area networks -- Bridges and Bridged Networks networks -- Bridges and Bridged Networks - Amendment 25:
- Amendment 25: Enhancements for Scheduled Traffic", 2015, Enhancements for Scheduled Traffic", IEEE Std. 802.1Qbv-
2015, DOI 10.1109/IEEESTD.2016.8613095, March 2016,
<https://ieeexplore.ieee.org/document/8613095>. <https://ieeexplore.ieee.org/document/8613095>.
[IEEE802.1Qch-2017] [IEEE802.1Qch-2017]
IEEE Standards Association, "IEEE Standard for Local and IEEE, "IEEE Standard for Local and metropolitan area
metropolitan area networks--Bridges and Bridged Networks-- networks--Bridges and Bridged Networks--Amendment 29:
Amendment 29: Cyclic Queuing and Forwarding", 2017, Cyclic Queuing and Forwarding", IEEE Std. 802.1Qch-2017,
DOI 10.1109/IEEESTD.2017.7961303, June 2017,
<https://ieeexplore.ieee.org/document/7961303>. <https://ieeexplore.ieee.org/document/7961303>.
[IETF_YANG_SEC] [IETF-YANG-SEC]
IETF, "YANG Module Security Considerations", 2018, IETF, "YANG module security considerations", October 2018,
<https://trac.ietf.org/trac/ops/wiki/yang-security- <https://trac.ietf.org/trac/ops/wiki/yang-security-
guidelines>. guidelines>.
[IT_DEF] Wikipedia, "IT Definition", 2020, [IPSECME-G-IKEV2]
<https://en.wikiquote.org/wiki/Information_technology>. Smyslov, V. and B. Weis, "Group Key Management using
IKEv2", Work in Progress, Internet-Draft, draft-ietf-
ipsecme-g-ikev2-02, 11 January 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-ipsecme-
g-ikev2-02>.
[OT_DEF] Wikipedia, "OT Definition", 2020, [IT-DEF] Wikipedia, "Information technology", March 2020,
<https://en.wikipedia.org/wiki/Operational_technology>. <https://en.wikiquote.org/w/
index.php?title=Information_technology&oldid=2749907>.
[MPLS-OPP-ENCRYPT]
Farrel, A. and S. Farrell, "Opportunistic Security in MPLS
Networks", Work in Progress, Internet-Draft, draft-ietf-
mpls-opportunistic-encrypt-03, 28 March 2017,
<https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
opportunistic-encrypt-03>.
[NS-DEF] Wikipedia, "Network segmentation", December 2020,
<https://en.wikipedia.org/w/
index.php?title=Network_segmentation&oldid=993163264>.
[OT-DEF] Wikipedia, "Operational technology", March 2021,
<https://en.wikipedia.org/w/
index.php?title=Operational_technology&oldid=1011704361>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS "Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474, Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998, DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>. <https://www.rfc-editor.org/info/rfc2474>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998, Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/info/rfc2475>. <https://www.rfc-editor.org/info/rfc2475>.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552,
DOI 10.17487/RFC3552, July 2003,
<https://www.rfc-editor.org/info/rfc3552>.
[RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation
Edge-to-Edge (PWE3) Architecture", RFC 3985, Edge-to-Edge (PWE3) Architecture", RFC 3985,
DOI 10.17487/RFC3985, March 2005, DOI 10.17487/RFC3985, March 2005,
<https://www.rfc-editor.org/info/rfc3985>. <https://www.rfc-editor.org/info/rfc3985>.
[RFC4107] Bellovin, S. and R. Housley, "Guidelines for Cryptographic
Key Management", BCP 107, RFC 4107, DOI 10.17487/RFC4107,
June 2005, <https://www.rfc-editor.org/info/rfc4107>.
[RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) [RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253, Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
January 2006, <https://www.rfc-editor.org/info/rfc4253>. January 2006, <https://www.rfc-editor.org/info/rfc4253>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the [RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>. December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC4302] Kent, S., "IP Authentication Header", RFC 4302, [RFC4302] Kent, S., "IP Authentication Header", RFC 4302,
DOI 10.17487/RFC4302, December 2005, DOI 10.17487/RFC4302, December 2005,
skipping to change at page 59, line 27 skipping to change at line 2752
<https://www.rfc-editor.org/info/rfc7835>. <https://www.rfc-editor.org/info/rfc7835>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
[RFC8578] Grossman, E., Ed., "Deterministic Networking Use Cases", [RFC8578] Grossman, E., Ed., "Deterministic Networking Use Cases",
RFC 8578, DOI 10.17487/RFC8578, May 2019, RFC 8578, DOI 10.17487/RFC8578, May 2019,
<https://www.rfc-editor.org/info/rfc8578>. <https://www.rfc-editor.org/info/rfc8578>.
[RS_DEF] Wikipedia, "RS Definition", 2020, [RFC9016] Varga, B., Farkas, J., Cummings, R., Jiang, Y., and D.
<https://en.wikipedia.org/wiki/Network_segmentation>. Fedyk, "Flow and Service Information Model for
Deterministic Networking (DetNet)", RFC 9016,
DOI 10.17487/RFC9016, March 2021,
<https://www.rfc-editor.org/info/rfc9016>.
[RFC9023] Varga, B., Ed., Farkas, J., Malis, A., and S. Bryant,
"Deterministic Networking (DetNet) Data Plane: IP over
IEEE 802.1 Time-Sensitive Networking (TSN)", RFC 9023,
DOI 10.17487/RFC9023, June 2021,
<https://www.rfc-editor.org/info/rfc9023>.
[RFC9025] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
MPLS over UDP/IP", RFC 9025, DOI 10.17487/RFC9025, April
2021, <https://www.rfc-editor.org/info/rfc9025>.
[RFC9056] Varga, B., Ed., Berger, L., Fedyk, D., Bryant, S., and J.
Korhonen, "Deterministic Networking (DetNet) Data Plane:
IP over MPLS", RFC 9056, DOI 10.17487/RFC9056, June 2021,
<https://www.rfc-editor.org/info/rfc9056>.
Contributors
The Editor would like to recognize the contributions of the following
individuals to this document.
Stewart Bryant
Futurewei Technologies
Email: sb@stewartbryant.com
David Black
Dell EMC
176 South Street
Hopkinton, Massachusetts 01748
United States of America
Henrik Austad
SINTEF Digital
Klaebuveien 153
7037 Trondheim
Norway
Email: henrik@austad.us
John Dowdell
Airbus Defence and Space
Celtic Springs
Newport, NP10 8FZ
United Kingdom
Email: john.dowdell.ietf@gmail.com
Norman Finn
3101 Rio Way
Spring Valley, California 91977
United States of America
Email: nfinn@nfinnconsulting.com
Subir Das
Applied Communication Sciences
150 Mount Airy Road
Basking Ridge, New Jersey 07920
United States of America
Email: sdas@appcomsci.com
Carsten Bormann
Universitat Bremen TZI
Postfach 330440 D-28359 Bremen
Germany
Email: cabo@tzi.org
Authors' Addresses Authors' Addresses
Ethan Grossman (editor) Ethan Grossman (editor)
Dolby Laboratories, Inc. Dolby Laboratories, Inc.
1275 Market Street 1275 Market Street
San Francisco, CA 94103 San Francisco, CA 94103
USA United States of America
Phone: +1 415 465 4339
Email: ethan@ieee.org Email: ethan@ieee.org
URI: http://www.dolby.com URI: https://www.dolby.com
Tal Mizrahi Tal Mizrahi
Huawei Network.IO Innovation Lab Huawei
Email: tal.mizrahi.phd@gmail.com Email: tal.mizrahi.phd@gmail.com
Andrew J. Hacker
MistIQ Technologies, Inc Andrew J. Hacker
Thought LLC
Harrisburg, PA Harrisburg, PA
USA United States of America
Email: ajhacker@mistiqtech.com Email: andrew@thought.live
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