I2RS working group S. Hares
Internet-Draft Huawei
Intended status: Standards Track D. Migault
Expires: February 28, 2016 J. Halpern
August 27, 2015

I2RS Security Related Requirements


This presents security-related requirements for the I2RS protocol for mutual authentication, transport protocols, data transfer and transactions.

Status of This Memo

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Table of Contents

1. Introduction

The Interface to the Routing System (I2RS) provides read and write access to information and state within the routing process. The I2RS client interacts with one or more I2RS agents to collect information from network routing systems.

This document describes the requirements for the I2RS protocol in the security-related areas of mutual authentication of the I2RS client and agent, the transport protocol carrying the I2RS protocol messages, and the atomicity of the transactions. These requirements align with the description of the I2RS architecture found in [I-D.ietf-i2rs-architecture] document.

[I-D.haas-i2rs-ephemeral-state-reqs] discusses I2RS roles-based write conflict resolution in the ephemeral data store using the I2RS Client Identity, I2RS Secondary Identity and priority. The draft [I-D.ietf-i2rs-traceability] describes the traceability framework and its requirements for I2RS. The draft [I-D.ietf-i2rs-pub-sub-requirements] describes the requirements for I2RS to be able to publish information or have a remote client subscribe to an information data stream.

1.1. Definitions

This document utilizes the definitions found in the following drafts: [RFC4949], and [I-D.ietf-i2rs-architecture]

Specifically, this document utilizes the following definitions:

access control

[RFC4949] defines access control as the following:
1)(I))protection of system resources against unauthorized use;
2)(I)process by which use of system resources is regulated according to a security policy and is permitted only by authorized entities (users, programs, processes, or other systems) according to that policy;
3)(I) (formal model) Limitations on interactions between subjects and objects in an information system;
4)(O) "The prevention of unauthorized use of a resource, including the prevention of use of a resource in an unauthorized manner.";
5.(O) /U.S. Government/ A system using physical, electronic, or human controls to identify or admit personnel with properly authorized access to a SCIF.


[RFC4949] describes authentication as the process of verifying (i.e., establishing the truth of) an attribute value claimed by or for a system entity or system resource. Authentication has two steps: identify and verify.
Data Confidentiality

[RFC4949] describes data confidentiality as having two properties: a) data is not disclosed to system entities unless they have been authorized to know, and b) data is not disclosed to unauthorized individuals, entities or processes. The key point is that confidentiality implies that the originator has the ability to authorize where the information goes. Confidentiality is important for both read and write scope of the data.
Data Integrity

[RFC4949] states data integrity includes
1. (I)The property that data has not been changed, destroyed, or
2. (O) "The property that information has not been modified or destroyed in an unauthorized manner."

Data Privacy

[RFC4949] describes data privacy as a synonym for data confidentiality. This I2RS document will utilize data privacy as a synonym for data confidentiality.
Mutual Authentication

[RFC4949] implies that mutual authentication exists between two interacting system entities. Mutual authentication in I2RS implies that both sides move from a state of mutual suspicion to mutually authenticated communication afte each system has been identified and validated by its peer system.

[RFC4949] describes role as:
1) (I) A job function or employment position to which people or other system entities may be assigned in a system. (See: role- based access control. Compare: duty, billet, principal, user.)
2) (O) /Common Criteria/ A pre-defined set of rules establishing the allowed interactions between a user and the TOE.

The I2RS uses the common criteria definition.


[RFC4949] describes role-based access control as: (I) A form of identity-based access control wherein the system entities that are identified and controlled are functional positions in an organization or process.
Security audit trail

[RFC4949] (page 254) describes a security audit trail as a chronological record of system activities that is sufficient to enable the reconstruction and examination of the sequence environments and activities surrounding or leading to an operation, procedure, or event in a security-relevant transaction from inception to final results. Requirements to support a security audit is not covered in this document. The draft [I-D.ietf-i2rs-traceability] describes traceability for I2RS interface and protocol. Traceability is not equivalent to a security audit trail.

I2RS the following phrase that incorporates an [RFC4949] definition:

I2RS protocol data integrity

The transfer of data via the I2RS protocol has the property of data integrity described in [RFC4949].

2. Security-Related Requirements

The security for the I2RS protocol requires mutually authenticated I2RS clients and I2RS agents. The I2RS client and I2RS agent using the I2RS protocol MUST be able to exchange data over a secure transport, but some functions may operate on non-secure transport. The I2RS protocol MUST BE able to provide atomicity of a transaction, but it is not required to have multi-message atomicity and rollback mechanism transactions. Multiple messages transactions may be impacted by the interdependency of data. This section discusses these details of these security requirements.

2.1. Mutual authentication of I2RS client and I2RS Agent

The I2RS architecture [I-D.ietf-i2rs-architecture] sets the following requirements:

2.2. Transport Requirements Based on Mutual Authentication

SEC-REQ-09: The I2RS protocol MUST be able to transfer data over a secure transport and optionally be able to transfer data over a non-secure transport. A secure transport MUST provide data confidentiality, data integrity, and replay prevention.

Note:The non-secure transport be used for publishing telemetry data that was specifically indicated to non-confidential in the data model. The configuration of ephemeral data in the I2RS Agent by the I2RS client SHOULD be done over a secure transport. It is anticipated that the passing of most I2RS ephemeral state operational status SHOULD be done over a secure transport. Data models SHOULD clearly annotate what data nodes can be passed over an insecure connection. The default transport is a secure transport.

SEC-REQ-10: A secure transport MUST be associated with a key management solution that can guarantee that only the entities having sufficient privileges can get the keys to encrypt/decrypt the sensitive data. Per BCP107 [RFC4107] this key management system SHOULD be automatic, but MAY BE manual if the following constraints from BCP107:

Most I2RS environments (I2RS Client - I2S Agents) will not have this environment, but a few I2RS use case provide limited non-secure light-weight telemetry messages that have these requirements. An I2RS data model must indicate which portions can be served by manual key management.

SEC-REQ-11: The I2RS protocol MUST be able to support multiple secure transport sessions providing protocol and data communication between an I2RS Agent and an I2RS client. However, a single I2RS Agent to I2RS client connection MAY elect to use a single secure transport session or a single non-secure transport session.

SEC-REQ-12: The I2RS Client and I2RS Agent protocol SHOULD implement mechanisms that mitigate DoS attacks

2.3. Data Confidentiality Requirements

SEC-REQ-13: In a critical infrastructure, certain data within routing elements is sensitive and read/write operations on such data MUST be controlled in order to protect its confidentiality. For example, most carriers do not want a router's configuration and data flow statistics known by hackers or their competitors. While carriers may share peering information, most carriers do not share configuration and traffic statistics. To achieve this, access control to sensitive data needs to be provided, and the confidentiality protection on such data during transportation needs to be enforced.

2.4. Data Integrity Requirements

SEC-REQ-14: An integrity protection mechanism for I2RS SHOULD be able to ensure the following: 1) the data being protected is not modified without detection during its transportation and 2) the data is actually from where it is expected to come from 3) the data is not repeated from some earlier interaction of the protocol. That is, when both confidentiality and integrity of data is properly protected, it is possible to ensure that encrypted data is not modified or replayed without detection.

SEC-REQ-15: The integrity that the message data is not repeated means that I2RS client to I2RS agent transport SHOULD protect against replay attack

Requirements SEC-REQ-13 and SEC-REQ-14 are SHOULD requirements only because it is recognized that some I2RS Client to I2RS agent communication occurs over a non-secure channel. The I2RS client to I2RS agent over a secure channel would implement these features. In order to provide some traceability or notification for the non-secure protocol, SEC-REQ-16 suggests traceability and notification are important to include for any non-secure protocol.

SEC-REQ-17: The I2RS message traceability and notification requirements requirements found in [I-D.ietf-i2rs-traceability] and [I-D.ietf-i2rs-pub-sub-requirements] SHOULD be supported in communication channel that is non-secure to trace or notify about potential security issues

2.5. Role-Based Data Model Security

The [I-D.ietf-i2rs-architecture] defines a role or security role as specifying read, write, or notification access by a I2RS client to data within an agent's data model.

SEC-REQ-18: The rules around what role is permitted to access and manipulate what information plus a secure transport (which protects the data in transit) SHOULD ensure that data of any level of sensitivity is reasonably protected from being observed by those without permission to view it, so that privacy requirements are met.

SEC-REQ-19: Role security MUST work when multiple transport connections are being used between the I2RS client and I2RS agent as the I2RS architecture [I-D.ietf-i2rs-architecture] states. These transport message streams may start/stop without affecting the existence of the client/agent data exchange. TCP supports a single stream of data. SCTP [RFC4960] provides security for multiple streams plus end-to-end transport of data.

SEC-REQ-20: I2RS clients MAY be used by multiple applications to configure routing via I2RS agents, receive status reports, turn on the I2RS audit stream, or turn on I2RS traceability. Application software using I2RS client functions may host several multiple secure identities, but each connection will use only one identifier with one priority. Therefore, the security of each I2RS Client to I2RS Agent connection is unique.

Please note the security of the application to I2RS client connection is outside of the I2RS protocol or I2RS interface.

3. Acknowledgement

The author would like to thank Wes George, Ahmed Abro, Qin Wu, Eric Yu, Joel Halpern, Scott Brim, Nancy Cam-Winget, DaCheng Zhang, Alia Atlas, and Jeff Haas for their contributions to the I2RS security requirements discussion and this document.

4. IANA Considerations

This draft includes no request to IANA.

5. Security Considerations

This is a document about security requirements for the I2RS protocol and data modules. The whole document is security considerations.

6. References

6.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC4107] Bellovin, S. and R. Housley, "Guidelines for Cryptographic Key Management", BCP 107, RFC 4107, DOI 10.17487/RFC4107, June 2005.

6.2. Informative References

[I-D.haas-i2rs-ephemeral-state-reqs] Haas, J., "I2RS Ephemeral State Requirements", Internet-Draft draft-haas-i2rs-ephemeral-state-reqs-00, May 2015.
[I-D.ietf-i2rs-architecture] Atlas, A., Halpern, J., Hares, S., Ward, D. and T. Nadeau, "An Architecture for the Interface to the Routing System", Internet-Draft draft-ietf-i2rs-architecture-09, March 2015.
[I-D.ietf-i2rs-problem-statement] Atlas, A., Nadeau, T. and D. Ward, "Interface to the Routing System Problem Statement", Internet-Draft draft-ietf-i2rs-problem-statement-06, January 2015.
[I-D.ietf-i2rs-pub-sub-requirements] Voit, E., Clemm, A. and A. Prieto, "Requirements for Subscription to YANG Datastores", Internet-Draft draft-ietf-i2rs-pub-sub-requirements-02, March 2015.
[I-D.ietf-i2rs-rib-info-model] Bahadur, N., Folkes, R., Kini, S. and J. Medved, "Routing Information Base Info Model", Internet-Draft draft-ietf-i2rs-rib-info-model-06, March 2015.
[I-D.ietf-i2rs-traceability] Clarke, J., Salgueiro, G. and C. Pignataro, "Interface to the Routing System (I2RS) Traceability: Framework and Information Model", Internet-Draft draft-ietf-i2rs-traceability-03, May 2015.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007.
[RFC4960] Stewart, R., "Stream Control Transmission Protocol", RFC 4960, DOI 10.17487/RFC4960, September 2007.

Authors' Addresses

Susan Hares Huawei 7453 Hickory Hill Saline, MI 48176 USA EMail: shares@ndzh.com
Daniel Migault Ericsson 8400 boulevard Decarie Montreal, QC HAP 2N2 Canada EMail: daniel.migault@ericsson.com
Joel Halpern Ericsson US EMail: joel.halpern@ericsson.com