draft-ietf-anima-bootstrapping-keyinfra-25.txt   draft-ietf-anima-bootstrapping-keyinfra-26.txt 
ANIMA WG M. Pritikin ANIMA WG M. Pritikin
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track M. Richardson Intended status: Standards Track M. Richardson
Expires: February 13, 2020 Sandelman Expires: February 15, 2020 Sandelman
T. Eckert T. Eckert
Futurewei USA Futurewei USA
M. Behringer M. Behringer
K. Watsen K. Watsen
Watsen Networks Watsen Networks
August 12, 2019 August 14, 2019
Bootstrapping Remote Secure Key Infrastructures (BRSKI) Bootstrapping Remote Secure Key Infrastructures (BRSKI)
draft-ietf-anima-bootstrapping-keyinfra-25 draft-ietf-anima-bootstrapping-keyinfra-26
Abstract Abstract
This document specifies automated bootstrapping of an Autonomic This document specifies automated bootstrapping of an Autonomic
Control Plane. To do this a Remote Secure Key Infrastructure (BRSKI) Control Plane. To do this a Remote Secure Key Infrastructure (BRSKI)
is created using manufacturer installed X.509 certificates, in is created using manufacturer installed X.509 certificates, in
combination with a manufacturer's authorizing service, both online combination with a manufacturer's authorizing service, both online
and offline. Bootstrapping a new device can occur using a routable and offline. Bootstrapping a new device can occur using a routable
address and a cloud service, or using only link-local connectivity, address and a cloud service, or using only link-local connectivity,
or on limited/disconnected networks. Support for lower security or on limited/disconnected networks. Support for lower security
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 13, 2020. This Internet-Draft will expire on February 15, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Prior Bootstrapping Approaches . . . . . . . . . . . . . 6 1.1. Prior Bootstrapping Approaches . . . . . . . . . . . . . 6
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
1.3. Scope of solution . . . . . . . . . . . . . . . . . . . . 10 1.3. Scope of solution . . . . . . . . . . . . . . . . . . . . 10
1.3.1. Support environment . . . . . . . . . . . . . . . . . 10 1.3.1. Support environment . . . . . . . . . . . . . . . . . 10
1.3.2. Constrained environments . . . . . . . . . . . . . . 11 1.3.2. Constrained environments . . . . . . . . . . . . . . 11
1.3.3. Network Access Controls . . . . . . . . . . . . . . . 11 1.3.3. Network Access Controls . . . . . . . . . . . . . . . 12
1.3.4. Bootstrapping is not Booting . . . . . . . . . . . . 12 1.3.4. Bootstrapping is not Booting . . . . . . . . . . . . 12
1.4. Leveraging the new key infrastructure / next steps . . . 12 1.4. Leveraging the new key infrastructure / next steps . . . 12
1.5. Requirements for Autonomic Network Infrastructure (ANI) 1.5. Requirements for Autonomic Network Infrastructure (ANI)
devices . . . . . . . . . . . . . . . . . . . . . . . . . 12 devices . . . . . . . . . . . . . . . . . . . . . . . . . 12
2. Architectural Overview . . . . . . . . . . . . . . . . . . . 13 2. Architectural Overview . . . . . . . . . . . . . . . . . . . 13
2.1. Behavior of a Pledge . . . . . . . . . . . . . . . . . . 15 2.1. Behavior of a Pledge . . . . . . . . . . . . . . . . . . 15
2.2. Secure Imprinting using Vouchers . . . . . . . . . . . . 16 2.2. Secure Imprinting using Vouchers . . . . . . . . . . . . 16
2.3. Initial Device Identifier . . . . . . . . . . . . . . . . 17 2.3. Initial Device Identifier . . . . . . . . . . . . . . . . 17
2.3.1. Identification of the Pledge . . . . . . . . . . . . 17 2.3.1. Identification of the Pledge . . . . . . . . . . . . 17
2.3.2. MASA URI extension . . . . . . . . . . . . . . . . . 18 2.3.2. MASA URI extension . . . . . . . . . . . . . . . . . 18
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Registrar) . . . . . . . . . . . . . . . . . . . . . . . . . 32 Registrar) . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.1. Pledge discovery of Proxy . . . . . . . . . . . . . . . . 33 4.1. Pledge discovery of Proxy . . . . . . . . . . . . . . . . 33
4.1.1. Proxy GRASP announcements . . . . . . . . . . . . . . 34 4.1.1. Proxy GRASP announcements . . . . . . . . . . . . . . 34
4.2. CoAP connection to Registrar . . . . . . . . . . . . . . 35 4.2. CoAP connection to Registrar . . . . . . . . . . . . . . 35
4.3. Proxy discovery and communication of Registrar . . . . . 36 4.3. Proxy discovery and communication of Registrar . . . . . 36
5. Protocol Details (Pledge - Registrar - MASA) . . . . . . . . 37 5. Protocol Details (Pledge - Registrar - MASA) . . . . . . . . 37
5.1. BRSKI-EST TLS establishment details . . . . . . . . . . . 39 5.1. BRSKI-EST TLS establishment details . . . . . . . . . . . 39
5.2. Pledge Requests Voucher from the Registrar . . . . . . . 40 5.2. Pledge Requests Voucher from the Registrar . . . . . . . 40
5.3. Registrar Authorization of 5.3. Registrar Authorization of
Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 41 Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.4. BRSKI-MASA TLS establishment details . . . . . . . . . . 42 5.4. BRSKI-MASA TLS establishment details . . . . . . . . . . 41
5.4.1. MASA authentication of 5.4.1. MASA authentication of
customer Registrar . . . . . . . . . . . . . . . . . 42 customer Registrar . . . . . . . . . . . . . . . . . 42
5.5. Registrar Requests Voucher from MASA . . . . . . . . . . 43 5.5. Registrar Requests Voucher from MASA . . . . . . . . . . 43
5.5.1. MASA renewal of expired vouchers . . . . . . . . . . 45 5.5.1. MASA renewal of expired vouchers . . . . . . . . . . 45
5.5.2. MASA verification of voucher-request signature 5.5.2. MASA pinning of registrar . . . . . . . . . . . . . . 45
consistency . . . . . . . . . . . . . . . . . . . . . 45 5.5.3. MASA checking of voucher request signature . . . . . 45
5.5.3. MASA authentication of registrar (certificate) . . . 45 5.5.4. MASA verification of domain registrar . . . . . . . . 46
5.5.4. MASA revocation checking of registrar (certificate) . 45
5.5.5. MASA verification of pledge prior-signed-voucher- 5.5.5. MASA verification of pledge prior-signed-voucher-
request . . . . . . . . . . . . . . . . . . . . . . . 46 request . . . . . . . . . . . . . . . . . . . . . . . 46
5.5.6. MASA pinning of registrar . . . . . . . . . . . . . . 46 5.5.6. MASA nonce handling . . . . . . . . . . . . . . . . . 47
5.5.7. MASA nonce handling . . . . . . . . . . . . . . . . . 46 5.6. MASA and Registrar Voucher Response . . . . . . . . . . . 47
5.6. MASA and Registrar Voucher Response . . . . . . . . . . . 46 5.6.1. Pledge voucher verification . . . . . . . . . . . . . 50
5.6.1. Pledge voucher verification . . . . . . . . . . . . . 49
5.6.2. Pledge authentication of provisional TLS connection . 50 5.6.2. Pledge authentication of provisional TLS connection . 50
5.7. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 51 5.7. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 51
5.8. Registrar audit log request . . . . . . . . . . . . . . . 52 5.8. Registrar audit-log request . . . . . . . . . . . . . . . 52
5.8.1. MASA audit log response . . . . . . . . . . . . . . . 53 5.8.1. MASA audit log response . . . . . . . . . . . . . . . 54
5.8.2. Registrar audit log verification . . . . . . . . . . 54 5.8.2. Calculation of domainID . . . . . . . . . . . . . . . 55
5.9. EST Integration for PKI bootstrapping . . . . . . . . . . 56 5.8.3. Registrar audit log verification . . . . . . . . . . 56
5.9.1. EST Distribution of CA Certificates . . . . . . . . . 56 5.9. EST Integration for PKI bootstrapping . . . . . . . . . . 57
5.9.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 56 5.9.1. EST Distribution of CA Certificates . . . . . . . . . 57
5.9.3. EST Client Certificate Request . . . . . . . . . . . 57 5.9.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 58
5.9.4. Enrollment Status Telemetry . . . . . . . . . . . . . 57 5.9.3. EST Client Certificate Request . . . . . . . . . . . 59
5.9.5. Multiple certificates . . . . . . . . . . . . . . . . 58 5.9.4. Enrollment Status Telemetry . . . . . . . . . . . . . 59
5.9.6. EST over CoAP . . . . . . . . . . . . . . . . . . . . 59 5.9.5. Multiple certificates . . . . . . . . . . . . . . . . 60
6. Clarification of transfer-encoding . . . . . . . . . . . . . 59 5.9.6. EST over CoAP . . . . . . . . . . . . . . . . . . . . 60
7. Reduced security operational modes . . . . . . . . . . . . . 59 6. Clarification of transfer-encoding . . . . . . . . . . . . . 60
7.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 59 7. Reduced security operational modes . . . . . . . . . . . . . 60
7.2. Pledge security reductions . . . . . . . . . . . . . . . 60 7.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 61
7.3. Registrar security reductions . . . . . . . . . . . . . . 61 7.2. Pledge security reductions . . . . . . . . . . . . . . . 61
7.4. MASA security reductions . . . . . . . . . . . . . . . . 62 7.3. Registrar security reductions . . . . . . . . . . . . . . 62
7.4.1. Issuing Nonceless vouchers . . . . . . . . . . . . . 62 7.4. MASA security reductions . . . . . . . . . . . . . . . . 63
7.4.2. Trusting Owners on First Use . . . . . . . . . . . . 63 7.4.1. Issuing Nonceless vouchers . . . . . . . . . . . . . 63
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 63 7.4.2. Trusting Owners on First Use . . . . . . . . . . . . 64
8.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 64 7.4.3. Updating or extending voucher trust anchors . . . . . 65
8.2. Well-known EST registration . . . . . . . . . . . . . . . 64 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 66
8.3. PKIX Registry . . . . . . . . . . . . . . . . . . . . . . 64 8.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 66
8.4. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 64 8.2. Well-known EST registration . . . . . . . . . . . . . . . 66
8.5. DNS Service Names . . . . . . . . . . . . . . . . . . . . 65 8.3. PKIX Registry . . . . . . . . . . . . . . . . . . . . . . 66
8.6. MUD File Extension for the MASA . . . . . . . . . . . . . 65 8.4. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 66
9. Applicability to the Autonomic 8.5. DNS Service Names . . . . . . . . . . . . . . . . . . . . 67
Control Plane . . . . . . . . . . . . . . . . . . . . . . . . 65 8.6. MUD File Extension for the MASA . . . . . . . . . . . . . 67
10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 66 9. Applicability to the Autonomic Control Plane (ACP) . . . . . 67
10.1. MASA audit log . . . . . . . . . . . . . . . . . . . . . 66 10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 68
10.2. What BRSKI-MASA reveals to the manufacturer . . . . . . 67 10.1. MASA audit log . . . . . . . . . . . . . . . . . . . . . 68
10.3. Manufacturers and Used or Stolen Equipment . . . . . . . 69 10.2. What BRSKI-EST reveals to the registrar . . . . . . . . 69
10.4. Manufacturers and Grey market equipment . . . . . . . . 70 10.3. What BRSKI-MASA reveals to the manufacturer . . . . . . 69
10.5. Some mitigations for meddling by manufacturers . . . . . 70 10.4. Manufacturers and Used or Stolen Equipment . . . . . . . 71
11. Security Considerations . . . . . . . . . . . . . . . . . . . 71 10.5. Manufacturers and Grey market equipment . . . . . . . . 72
11.1. Denial of Service (DoS) against MASA . . . . . . . . . . 72 10.6. Some mitigations for meddling by manufacturers . . . . . 73
11.2. Freshness in Voucher-Requests . . . . . . . . . . . . . 73 11. Security Considerations . . . . . . . . . . . . . . . . . . . 74
11.3. Trusting manufacturers . . . . . . . . . . . . . . . . . 74 11.1. Denial of Service (DoS) against MASA . . . . . . . . . . 75
11.4. Manufacturer Maintenance of trust anchors . . . . . . . 75 11.2. Availability of good random numbers . . . . . . . . . . 76
11.4.1. Compromise of Manufacturer IDevID signing keys . . . 77 11.3. Freshness in Voucher-Requests . . . . . . . . . . . . . 76
11.4.2. Compromise of MASA signing keys . . . . . . . . . . 77 11.4. Trusting manufacturers . . . . . . . . . . . . . . . . . 77
11.4.3. Compromise of MASA web service . . . . . . . . . . . 79 11.5. Manufacturer Maintenance of trust anchors . . . . . . . 78
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 80 11.5.1. Compromise of Manufacturer IDevID signing keys . . . 79
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 80 11.5.2. Compromise of MASA signing keys . . . . . . . . . . 80
13.1. Normative References . . . . . . . . . . . . . . . . . . 80 11.5.3. Compromise of MASA web service . . . . . . . . . . . 82
13.2. Informative References . . . . . . . . . . . . . . . . . 83 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 82
Appendix A. IPv4 and non-ANI operations . . . . . . . . . . . . 86 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 83
A.1. IPv4 Link Local addresses . . . . . . . . . . . . . . . . 87 13.1. Normative References . . . . . . . . . . . . . . . . . . 83
A.2. Use of DHCPv4 . . . . . . . . . . . . . . . . . . . . . . 87 13.2. Informative References . . . . . . . . . . . . . . . . . 86
Appendix B. mDNS / DNSSD proxy discovery options . . . . . . . . 87 Appendix A. IPv4 and non-ANI operations . . . . . . . . . . . . 89
Appendix C. MUD Extension . . . . . . . . . . . . . . . . . . . 88 A.1. IPv4 Link Local addresses . . . . . . . . . . . . . . . . 90
Appendix D. Example Vouchers . . . . . . . . . . . . . . . . . . 90 A.2. Use of DHCPv4 . . . . . . . . . . . . . . . . . . . . . . 90
D.1. Keys involved . . . . . . . . . . . . . . . . . . . . . . 90 Appendix B. mDNS / DNSSD proxy discovery options . . . . . . . . 90
D.1.1. MASA key pair for voucher signatures . . . . . . . . 90 Appendix C. MUD Extension . . . . . . . . . . . . . . . . . . . 91
D.1.2. Manufacturer key pair for IDevID signatures . . . . . 90 Appendix D. Example Vouchers . . . . . . . . . . . . . . . . . . 93
D.1.3. Registrar key pair . . . . . . . . . . . . . . . . . 91 D.1. Keys involved . . . . . . . . . . . . . . . . . . . . . . 93
D.1.4. Pledge key pair . . . . . . . . . . . . . . . . . . . 93 D.1.1. MASA key pair for voucher signatures . . . . . . . . 93
D.2. Example process . . . . . . . . . . . . . . . . . . . . . 94 D.1.2. Manufacturer key pair for IDevID signatures . . . . . 93
D.2.1. Pledge to Registrar . . . . . . . . . . . . . . . . . 95 D.1.3. Registrar key pair . . . . . . . . . . . . . . . . . 94
D.2.2. Registrar to MASA . . . . . . . . . . . . . . . . . . 98 D.1.4. Pledge key pair . . . . . . . . . . . . . . . . . . . 96
D.2.3. MASA to Registrar . . . . . . . . . . . . . . . . . . 103 D.2. Example process . . . . . . . . . . . . . . . . . . . . . 97
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 107 D.2.1. Pledge to Registrar . . . . . . . . . . . . . . . . . 98
D.2.2. Registrar to MASA . . . . . . . . . . . . . . . . . . 101
D.2.3. MASA to Registrar . . . . . . . . . . . . . . . . . . 106
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 110
1. Introduction 1. Introduction
BRSKI provides a solution for secure zero-touch (automated) bootstrap BRSKI provides a solution for secure zero-touch (automated) bootstrap
of new (unconfigured) devices that are called pledges in this of new (unconfigured) devices that are called pledges in this
document. document.
This document primarily provides for the needs of the ISP and This document primarily provides for the needs of the ISP and
Enterprise focused ANIMA Autonomic Control Plane (ACP) Enterprise focused ANIMA Autonomic Control Plane (ACP)
[I-D.ietf-anima-autonomic-control-plane]. This bootstrap process [I-D.ietf-anima-autonomic-control-plane]. This bootstrap process
satisfies the [RFC7575] section 3.3 of making all operations secure satisfies the [RFC7575] section 3.3 of making all operations secure
by default. Other users of the BRSKI protocol will need to provide by default. Other users of the BRSKI protocol will need to provide
separate applicability statements that include privacy and security separate applicability statements that include privacy and security
considerations appropriate to that deployment. Section 9 explains considerations appropriate to that deployment. Section 9 explains
the details applicability for this the ACP usage. the details applicability for this the ACP usage.
The BRSKI protocol requires a significant amount of communication
between manufacturer and owner: in it's default modes it provides a
cryptographic transfer of control to the initial owner. In it's
strongest modes, it leverages sales channel information to identify
the owner in advance. Resale of devices is possible, provided that
the manufacturer is willing to authorize the transfer. Mechanisms to
enable transfers of ownership without manufacturer authorization are
not included in this version of the protocol, but could be designed
into future versions.
This document describes how pledges discover (or are discovered by) This document describes how pledges discover (or are discovered by)
an element of the network domain to which the pledge belongs that an element of the network domain to which the pledge belongs that
will perform the bootstrap. This element (device) is called the will perform the bootstrap. This element (device) is called the
registrar. Before any other operation, pledge and registrar need to registrar. Before any other operation, pledge and registrar need to
establish mutual trust: establish mutual trust:
1. Registrar authenticating the pledge: "Who is this device? What 1. Registrar authenticating the pledge: "Who is this device? What
is its identity?" is its identity?"
2. Registrar authorizing the pledge: "Is it mine? Do I want it? 2. Registrar authorizing the pledge: "Is it mine? Do I want it?
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1.2. Terminology 1.2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
The following terms are defined for clarity: The following terms are defined for clarity:
domainID: The domain IDentity is a unique hash based upon a domainID: The domain IDentity is a unique hash based upon the
Registrar's certificate. If the certificate includes the Registrar CA's certificate. Section 5.8.2 specifies how it is
SubjectKeyIdentifier (Section 4.2.1.2 [RFC5280]), then it is to be calculated.
used as the domainID. If not, then the 160-bit SHA-1 hash as
described in that section is to be used. This value needs to be
calculated by both MASA (to populate the audit log), and by the
Registrar (to recognize itself).
drop-ship: The physical distribution of equipment containing the drop-ship: The physical distribution of equipment containing the
"factory default" configuration to a final destination. In zero- "factory default" configuration to a final destination. In zero-
touch scenarios there is no staging or pre-configuration during touch scenarios there is no staging or pre-configuration during
drop-ship. drop-ship.
imprint: The process where a device obtains the cryptographic key imprint: The process where a device obtains the cryptographic key
material to identify and trust future interactions with a network. material to identify and trust future interactions with a network.
This term is taken from Konrad Lorenz's work in biology with new This term is taken from Konrad Lorenz's work in biology with new
ducklings: during a critical period, the duckling would assume ducklings: during a critical period, the duckling would assume
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they are communicating with a proxy rather than directly with a they are communicating with a proxy rather than directly with a
registrar. registrar.
Circuit Proxy: A stateful implementation of the join proxy. This is Circuit Proxy: A stateful implementation of the join proxy. This is
the assumed type of proxy. the assumed type of proxy.
IPIP Proxy: A stateless proxy alternative. IPIP Proxy: A stateless proxy alternative.
MASA Service: A third-party Manufacturer Authorized Signing MASA Service: A third-party Manufacturer Authorized Signing
Authority (MASA) service on the global Internet. The MASA signs Authority (MASA) service on the global Internet. The MASA signs
vouchers. It also provides a repository for audit log information vouchers. It also provides a repository for audit-log information
of privacy protected bootstrapping events. It does not track of privacy protected bootstrapping events. It does not track
ownership. ownership.
MASA Audit Log: A list of previous owners maintained by the MASA on MASA Audit-Log: A list of previous owners maintained by the MASA on
a per device (per pledge) basis. Described in Section 5.8.1. a per device (per pledge) basis. Described in Section 5.8.1.
Ownership Tracker: An Ownership Tracker service on the global Ownership Tracker: An Ownership Tracker service on the global
Internet. The Ownership Tracker uses business processes to Internet. The Ownership Tracker uses business processes to
accurately track ownership of all devices shipped against domains accurately track ownership of all devices shipped against domains
that have purchased them. Although optional, this component that have purchased them. Although optional, this component
allows vendors to provide additional value in cases where their allows vendors to provide additional value in cases where their
sales and distribution channels allow for accurately tracking of sales and distribution channels allow for accurately tracking of
such ownership. Ownership tracking information is indicated in such ownership. Ownership tracking information is indicated in
vouchers as described in [RFC8366] vouchers as described in [RFC8366]
skipping to change at page 17, line 25 skipping to change at page 17, line 25
PKIX-shaped certificate installed during the manufacturing process. PKIX-shaped certificate installed during the manufacturing process.
This is the 802.1AR Initial Device Identifier (IDevID), and it This is the 802.1AR Initial Device Identifier (IDevID), and it
provides a basis for authenticating the pledge during the protocol provides a basis for authenticating the pledge during the protocol
exchanges described here. There is no requirement for a common root exchanges described here. There is no requirement for a common root
PKI hierarchy. Each device manufacturer can generate its own root PKI hierarchy. Each device manufacturer can generate its own root
certificate. Specifically, the IDevID enables: certificate. Specifically, the IDevID enables:
1. Uniquely identifying the pledge by the Distinguished Name (DN) 1. Uniquely identifying the pledge by the Distinguished Name (DN)
and subjectAltName (SAN) parameters in the IDevID. The unique and subjectAltName (SAN) parameters in the IDevID. The unique
identification of a pledge in the voucher objects are derived identification of a pledge in the voucher objects are derived
from those parameters as described below. Section 10.2 discussed from those parameters as described below. Section 10.3 discussed
privacy implications. privacy implications.
2. Provides a cryptographic authentication of the pledge to the 2. Provides a cryptographic authentication of the pledge to the
Registrar (see Section 5.3). Registrar (see Section 5.3).
3. Secure auto-discovery of the pledge's MASA by the registrar (see 3. Secure auto-discovery of the pledge's MASA by the registrar (see
Section 2.8). Section 2.8).
4. Signing of voucher-request by the pledge's IDevID (see 4. Signing of voucher-request by the pledge's IDevID (see
Section 3). Section 3).
5. Provides a cryptographic authentication of the pledge to the MASA 5. Provides a cryptographic authentication of the pledge to the MASA
(see Section 5.5.5). (see Section 5.5.5).
Section 7.2.13 of [IDevID] discusses keyUsage and extendedKeyUsage Section 7.2.13 (2009 edition) and section 8.10.3 (2018 edition) of
extensions in the IDevID certificate. Any restrictions included [IDevID] discusses keyUsage and extendedKeyUsage extensions in the
reduce the utility of the IDevID and so this specification RECOMMENDS IDevID certificate. Any restrictions included reduce the utility of
that no key usage restrictions be included. Additionally, [RFC5280] the IDevID and so this specification RECOMMENDS that no key usage
section 4.2.1.3 does not require key usage restrictions for end restrictions be included. Additionally, [RFC5280] section 4.2.1.3
entity certificates. does not require key usage restrictions for end entity certificates.
2.3.1. Identification of the Pledge 2.3.1. Identification of the Pledge
In the context of BRSKI, pledges are uniquely identified by a In the context of BRSKI, pledges have a 1:1 relationship with a
"serial-number". This serial-number is used both in the "serial- "serial-number". This serial-number is used both in the "serial-
number" field of voucher or voucher-requests (see Section 3) and in number" field of voucher or voucher-requests (see Section 3) and in
local policies on registrar or MASA (see Section 5). local policies on registrar or MASA (see Section 5).
The following fields are defined in [IDevID] and [RFC5280]: The serialNumber fields is defined in [RFC5280], and is a SHOULD
field in [IDevID]. IDevID certificates for use with this protocol
o The subject field's DN encoding MUST include the "serialNumber" MUST include the "serialNumber" attribute with the device's unique
attribute with the device's unique serial number. (from [IDevID] serial number (from [IDevID] section 7.2.8, and [RFC5280] section
section 7.2.8, and [RFC5280] section 4.1.2.4's list of standard 4.1.2.4's list of standard attributes).
attributes)
o The subject-alt field's encoding MAY include a non-critical
version of the RFC4108 defined HardwareModuleName. (from [IDevID]
section 7.2.9) If the IDevID is stored in a Trusted Platform
Module (TPM), then this field MAY contain the TPM identification
rather than the device's serial number. If both fields are
present, then the subject field takes precedence.
and they are used as follows by the pledge to build the "serial-
number" that is placed in the voucher-request. In order to build it,
the fields need to be converted into a serial-number of "type
string". The following methods are used depending on the first
available IDevID certificate field (attempted in this order):
1. [RFC4519] section 2.31 provides an example ("WI-3005") of the The serialNumber field is used as follows by the pledge to build the
Distinguished Name "serialNumber" attribute. [RFC4514] indicates "serial-number" that is placed in the voucher-request. In order to
this is a printable string so no encoding is necessary. build it, the fields need to be converted into a serial-number of
"type string".
2. The HardwareModuleName hwSerialNum OCTET STRING. This value is An example of a printable form of the "serialNumber" field is
base64 encoded to convert it to a printable string format. provided in [RFC4519] section 2.31 ("WI-3005"). That section further
provides equality and syntax attributes.
The above process to locate the serial-number MUST be performed by Due to the reality of existing device identity provisioning
the pledge when filling out the voucher-request. Signed voucher- processes, some manufacturers have stored serial-numbers in other
requests are always passed up to the MASA. fields. Registrar's SHOULD be configurable, on a per-manufacturer
basis, to look for serial-number equivalents in other fields.
As explained in Section 5.5 the Registrar MUST extract the serial- As explained in Section 5.5 the Registrar MUST extract the serial-
number again itself from the pledge's TLS certificate. It can number again itself from the pledge's TLS certificate. It can
consult the serial-number in the pledge-request if there are any consult the serial-number in the pledge-request if there are any
possible confusion about the source of the serial-number (hwSerialNum possible confusion about the source of the serial-number.
vs serialNumber).
2.3.2. MASA URI extension 2.3.2. MASA URI extension
This document defines a new PKIX non-critical certificate extension This document defines a new PKIX non-critical certificate extension
to carry the MASA URI. This extension is intended to be used in the to carry the MASA URI. This extension is intended to be used in the
IDevID certificate. The URI is represented as described in IDevID certificate. The URI is represented as described in
Section 7.4 of [RFC5280]. Section 7.4 of [RFC5280].
The URI provides the authority information. The BRSKI "/.well-known" The URI provides the authority information. The BRSKI "/.well-known"
tree ([RFC5785]) is described in Section 5. tree ([RFC5785]) is described in Section 5.
skipping to change at page 22, line 30 skipping to change at page 22, line 30
about the registrar/owner. about the registrar/owner.
The manufacturer can then apply policy based on the provided The manufacturer can then apply policy based on the provided
information, as well as other sources of information (such as sales information, as well as other sources of information (such as sales
records), to decide whether to approve the claim by the registrar to records), to decide whether to approve the claim by the registrar to
own the device; if the claim is accepted, a voucher is issued that own the device; if the claim is accepted, a voucher is issued that
directs the device to accept its new owner. directs the device to accept its new owner.
The voucher is returned to the registrar, but not immediately to the The voucher is returned to the registrar, but not immediately to the
device -- the registrar has an opportunity to examine the voucher, device -- the registrar has an opportunity to examine the voucher,
the MASA's audit logs, and other sources of information to determine the MASA's audit-logs, and other sources of information to determine
whether the device has been tampered with, and whether the bootstrap whether the device has been tampered with, and whether the bootstrap
should be accepted. should be accepted.
No filtering of information is possible in the signed voucher, so No filtering of information is possible in the signed voucher, so
this is a binary yes-or-no decision. If the registrar accepts the this is a binary yes-or-no decision. If the registrar accepts the
voucher as a proper one for its device, the voucher is returned to voucher as a proper one for its device, the voucher is returned to
the pledge for imprinting. the pledge for imprinting.
The voucher also includes a trust anchor that the pledge uses as The voucher also includes a trust anchor that the pledge uses as
representing the owner. This is used to successfully bootstrap from representing the owner. This is used to successfully bootstrap from
skipping to change at page 24, line 8 skipping to change at page 24, line 8
enrollment of pledges with domain certificates. enrollment of pledges with domain certificates.
The voucher provides a method for the distribution of a single PKI The voucher provides a method for the distribution of a single PKI
trust anchor (as the "pinned-domain-cert"). A distribution of the trust anchor (as the "pinned-domain-cert"). A distribution of the
full set of current trust anchors is possible using the optional EST full set of current trust anchors is possible using the optional EST
integration. integration.
The domain's registrar acts as an [RFC5272] Registration Authority, The domain's registrar acts as an [RFC5272] Registration Authority,
requesting certificates for pledges from the Key Infrastructure. requesting certificates for pledges from the Key Infrastructure.
The expectations of the PKI are unchanged from EST [[RFC7030]]. This The expectations of the PKI are unchanged from EST [RFC7030]. This
document does not place any additional architectural requirements on document does not place any additional architectural requirements on
the Public Key Infrastructure. the Public Key Infrastructure.
2.6. Certificate Time Validation 2.6. Certificate Time Validation
2.6.1. Lack of realtime clock 2.6.1. Lack of realtime clock
Many devices when bootstrapping do not have knowledge of the current Many devices when bootstrapping do not have knowledge of the current
time. Mechanisms such as Network Time Protocols cannot be secured time. Mechanisms such as Network Time Protocols cannot be secured
until bootstrapping is complete. Therefore bootstrapping is defined until bootstrapping is complete. Therefore bootstrapping is defined
skipping to change at page 24, line 39 skipping to change at page 24, line 39
check the above time fields in all certificates and signatures that check the above time fields in all certificates and signatures that
ir processes. ir processes.
If the voucher contains a nonce then the pledge MUST confirm the If the voucher contains a nonce then the pledge MUST confirm the
nonce matches the original pledge voucher-request. This ensures the nonce matches the original pledge voucher-request. This ensures the
voucher is fresh. See Section 5.2. voucher is fresh. See Section 5.2.
2.6.2. Infinite Lifetime of IDevID 2.6.2. Infinite Lifetime of IDevID
[RFC5280] explains that long lived pledge certificates "SHOULD be [RFC5280] explains that long lived pledge certificates "SHOULD be
assigned the GeneralizedTime value of 99991231235959Z". Registrars assigned the GeneralizedTime value of 99991231235959Z" for the
MUST support such lifetimes and SHOULD support ignoring pledge notAfter field.
lifetimes if they did not follow the RFC5280 recommendations.
For example, IDevID may have incorrect lifetime of N <= 3 years, Some deployed IDevID management systems are not compliant with the
rendering replacement pledges from storage useless after N years 802.1AR requirement for infinite lifetimes, and put in typical <= 3
unless registrars support ignoring such a lifetime. year certificate lifetimes. Registrars SHOULD be configurable on a
per-manufacturer basis to ignore pledge lifetimes when they did not
follow the RFC5280 recommendations.
2.7. Cloud Registrar 2.7. Cloud Registrar
There exist operationally open networks wherein devices gain There exist operationally open networks wherein devices gain
unauthenticated access to the Internet at large. In these use cases unauthenticated access to the Internet at large. In these use cases
the management domain for the device needs to be discovered within the management domain for the device needs to be discovered within
the larger Internet. The case where a device can boot and get access the larger Internet. The case where a device can boot and get access
to larger Internet are less likely within the ANIMA ACP scope but may to larger Internet are less likely within the ANIMA ACP scope but may
be more important in the future. In the ANIMA ACP scope, new devices be more important in the future. In the ANIMA ACP scope, new devices
will be quarantined behind a Join Proxy. will be quarantined behind a Join Proxy.
skipping to change at page 25, line 21 skipping to change at page 25, line 22
instance). In such a future situation, the device might use this instance). In such a future situation, the device might use this
management interface to learn that it should configure itself to management interface to learn that it should configure itself to
become the local registrar. become the local registrar.
In order to support these scenarios, the pledge MAY contact a well In order to support these scenarios, the pledge MAY contact a well
known URI of a cloud registrar if a local registrar cannot be known URI of a cloud registrar if a local registrar cannot be
discovered or if the pledge's target use cases do not include a local discovered or if the pledge's target use cases do not include a local
registrar. registrar.
If the pledge uses a well known URI for contacting a cloud registrar If the pledge uses a well known URI for contacting a cloud registrar
an Implicit Trust Anchor database (see [RFC7030]) MUST be used to a manufacturer-assigned Implicit Trust Anchor database (see
authenticate that service as described in [RFC6125]. This is [RFC7030]) MUST be used to authenticate that service as described in
consistent with the human user configuration of an EST server URI in [RFC6125]. This is consistent with the human user configuration of
[RFC7030] which also depends on RFC6125. an EST server URI in [RFC7030] which also depends on RFC6125.
2.8. Determining the MASA to contact 2.8. Determining the MASA to contact
The registrar needs to be able to contact a MASA that is trusted by The registrar needs to be able to contact a MASA that is trusted by
the pledge in order to obtain vouchers. There are three mechanisms the pledge in order to obtain vouchers. There are three mechanisms
described: described:
The device's Initial Device Identifier (IDevID) will normally contain The device's Initial Device Identifier (IDevID) will normally contain
the MASA URL as detailed in Section 2.3. This is the RECOMMENDED the MASA URL as detailed in Section 2.3. This is the RECOMMENDED
mechanism. mechanism.
skipping to change at page 28, line 4 skipping to change at page 28, line 4
} }
} }
Figure 6: JSON representation of example Voucher-Request Figure 6: JSON representation of example Voucher-Request
Example (2) The following example illustrates a registrar voucher- Example (2) The following example illustrates a registrar voucher-
request. The 'prior-signed-voucher-request' leaf is request. The 'prior-signed-voucher-request' leaf is
populated with the pledge's voucher-request (such as the populated with the pledge's voucher-request (such as the
prior example). The pledge's voucher-request is a prior example). The pledge's voucher-request is a
binary CMS signed object. In the JSON encoding used binary CMS signed object. In the JSON encoding used
here it must be base64 encoded. The nonce, created-on here it must be base64 encoded. The nonce and assertion
and assertion is carried forward. The serial-number is MAY be carried forward from the pledge request to the
extracted from the pledge's Client Certificate from the registrar request. The serial-number is extracted from
TLS connection. See Section 5.5. the pledge's Client Certificate from the TLS connection.
See Section 5.5.
{ {
"ietf-voucher-request:voucher": { "ietf-voucher-request:voucher": {
"assertion" : "proximity", "assertion" : "proximity",
"nonce": "62a2e7693d82fcda2624de58fb6722e5", "nonce": "62a2e7693d82fcda2624de58fb6722e5",
"created-on": "2017-01-01T00:00:02.000Z", "created-on": "2017-01-01T00:00:02.000Z",
"idevid-issuer": "base64encodedvalue==" "idevid-issuer": "base64encodedvalue=="
"serial-number": "JADA123456789" "serial-number": "JADA123456789"
"prior-signed-voucher-request": "base64encodedvalue==" "prior-signed-voucher-request": "base64encodedvalue=="
} }
skipping to change at page 34, line 21 skipping to change at page 34, line 21
infrastructure. The back-off timer for each MUST be independent of infrastructure. The back-off timer for each MUST be independent of
other connection attempts. other connection attempts.
Connection attempts SHOULD be run in parallel to avoid head of queue Connection attempts SHOULD be run in parallel to avoid head of queue
problems wherein an attacker running a fake proxy or registrar could problems wherein an attacker running a fake proxy or registrar could
perform protocol actions intentionally slowly. Connection attempts perform protocol actions intentionally slowly. Connection attempts
to different proxies SHOULD be sent with an interval of 3 to 5s. The to different proxies SHOULD be sent with an interval of 3 to 5s. The
pledge SHOULD continue to listen to for additional GRASP M_FLOOD pledge SHOULD continue to listen to for additional GRASP M_FLOOD
messages during the connection attempts. messages during the connection attempts.
Each connection attempt through a distinct Join Proxy MUST have a
unique nonce in the voucher-request.
Once a connection to a registrar is established (e.g. establishment Once a connection to a registrar is established (e.g. establishment
of a TLS session key) there are expectations of more timely of a TLS session key) there are expectations of more timely
responses, see Section 5.2. responses, see Section 5.2.
Once all discovered services are attempted (assuming that none Once all discovered services are attempted (assuming that none
succeeded) the device MUST return to listening for GRASP M_FLOOD. It succeeded) the device MUST return to listening for GRASP M_FLOOD. It
SHOULD periodically retry any manufacturer-specific mechanisms. The SHOULD periodically retry any manufacturer-specific mechanisms. The
pledge MAY prioritize selection order as appropriate for the pledge MAY prioritize selection order as appropriate for the
anticipated environment. anticipated environment.
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described as extensions to EST within the same "/.well-known" tree. described as extensions to EST within the same "/.well-known" tree.
For clarity this channel is referred to as "BRSKI-MASA". (See For clarity this channel is referred to as "BRSKI-MASA". (See
Figure 1). Figure 1).
The MASA URI is "https://" authority "/.well-known/est". The MASA URI is "https://" authority "/.well-known/est".
BRSKI uses existing CMS message formats for existing EST operations. BRSKI uses existing CMS message formats for existing EST operations.
BRSKI uses JSON [RFC8259] for all new operations defined here, and BRSKI uses JSON [RFC8259] for all new operations defined here, and
voucher formats. voucher formats.
While EST section 3.2 does not insist upon use of HTTP 1.1 persistent While EST section 3.2 does not insist upon use of HTTP persistent
connections, ([RFC7230] section 6.3) BRSKI-EST connections SHOULD use connections, ([RFC7230] section 6.3) BRSKI-EST connections SHOULD use
persistent connections. The intention of this guidance is to ensure persistent connections. The intention of this guidance is to ensure
the provisional TLS state occurs only once, and that the subsequent the provisional TLS state occurs only once, and that the subsequent
resolution of the provision state is not subject to a MITM attack resolution of the provision state is not subject to a MITM attack
during a critical phase. during a critical phase.
If non-persistent connections are used, then both the pledge and the If non-persistent connections are used, then both the pledge and the
registrar MUST remember the certificates seen, and also sent for the registrar MUST remember the certificates seen, and also sent for the
first connection. They MUST check each subsequent connections for first connection. They MUST check each subsequent connections for
the same certificates, and each end MUST use the same certificates as the same certificates, and each end MUST use the same certificates as
skipping to change at page 39, line 18 skipping to change at page 39, line 18
the circuit proxy (see Section 4) but the TLS handshake is with the the circuit proxy (see Section 4) but the TLS handshake is with the
registrar. The BRSKI-EST pledge is the TLS client and the BRSKI-EST registrar. The BRSKI-EST pledge is the TLS client and the BRSKI-EST
registrar is the TLS server. All security associations established registrar is the TLS server. All security associations established
are between the pledge and the registrar regardless of proxy are between the pledge and the registrar regardless of proxy
operations. operations.
Establishment of the BRSKI-EST TLS connection is as specified in EST Establishment of the BRSKI-EST TLS connection is as specified in EST
[RFC7030] section 4.1.1 "Bootstrap Distribution of CA Certificates" [RFC7030] section 4.1.1 "Bootstrap Distribution of CA Certificates"
[RFC7030] wherein the client is authenticated with the IDevID [RFC7030] wherein the client is authenticated with the IDevID
certificate, and the EST server (the registrar) is provisionally certificate, and the EST server (the registrar) is provisionally
authenticated with an unverified server certificate. authenticated with an unverified server certificate. Configuration
or distribution of the trust anchor database used for validating the
IDevID certificate is out-of-scope of this specification. Note that
the trust anchors in/excluded from the database will affect which
manufacturers' devices are acceptable to the registrar as pledges,
and can also be used to limit the set of MASAs that are trusted for
enrollment.
The signatures in the certificate MUST be validated even if a signing The signatures in the certificate MUST be validated even if a signing
key can not (yet) be validated. The certificate (or chain) MUST be key can not (yet) be validated. The certificate (or chain) MUST be
retained for later validation. retained for later validation.
A self-signed certificate for the Registrar is acceptable as the A self-signed certificate for the Registrar is acceptable as the
voucher will validate it. voucher will validate it.
[RFC5280] section 4.2.1.2 does not mandate that the
SubjectKeyIdentifier extension be present in non-CA certificates. It
is RECOMMENDED that Registrar certificates (even if self-signed),
always include the SubjectKeyIdentifier to be used as a DomainID, and
that a hash stronger than SHA-1 be used.
The pledge performs input validation of all data received until a The pledge performs input validation of all data received until a
voucher is verified as specified in Section 5.6.1 and the TLS voucher is verified as specified in Section 5.6.1 and the TLS
connection leaves the provisional state. Until these operations are connection leaves the provisional state. Until these operations are
complete the pledge could be communicating with an attacker. complete the pledge could be communicating with an attacker.
The pledge code needs to be written with the assumption that all data The pledge code needs to be written with the assumption that all data
is being transmitted at this point to an unauthenticated peer, and is being transmitted at this point to an unauthenticated peer, and
that received data, while inside a TLS connection, MUST be considered that received data, while inside a TLS connection, MUST be considered
untrusted. This particularly applies to HTTP headers and CMS untrusted. This particularly applies to HTTP headers and CMS
structures that make up the voucher. structures that make up the voucher.
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first certificate in the TLS server 'certificate_list' sequence first certificate in the TLS server 'certificate_list' sequence
(see [RFC5246]) presented by the registrar to the pledge. That (see [RFC5246]) presented by the registrar to the pledge. That
is, it is the end-entity certificate. This MUST be populated in a is, it is the end-entity certificate. This MUST be populated in a
pledge voucher-request if the "proximity" assertion is populated. pledge voucher-request if the "proximity" assertion is populated.
All other fields MAY be omitted in the pledge voucher-request. All other fields MAY be omitted in the pledge voucher-request.
An example JSON payload of a pledge voucher-request is in Section 3.3 An example JSON payload of a pledge voucher-request is in Section 3.3
Example 1. Example 1.
The registrar validates the client identity as described in EST
[RFC7030] section 3.3.2.
The registrar confirms that the assertion is 'proximity' and that The registrar confirms that the assertion is 'proximity' and that
pinned 'proximity-registrar-cert' is the Registrar's certificate. If pinned 'proximity-registrar-cert' is the Registrar's certificate. If
this validation fails, then there a On-Path Attacker (MITM), and the this validation fails, then there a On-Path Attacker (MITM), and the
connection MUST be closed after the returning an HTTP 401 error code. connection MUST be closed after the returning an HTTP 401 error code.
5.3. Registrar Authorization of Pledge 5.3. Registrar Authorization of Pledge
In a fully automated network all devices must be securely identified In a fully automated network all devices must be securely identified
and authorized to join the domain. and authorized to join the domain.
skipping to change at page 42, line 29 skipping to change at page 42, line 23
Registars SHOULD permit trust anchors to be pre-configured on a per- Registars SHOULD permit trust anchors to be pre-configured on a per-
vendor(MASA) basis. Registrars SHOULD include the ability to vendor(MASA) basis. Registrars SHOULD include the ability to
configure a TLS ClientCertificate on a per-MASA basis, or to use no configure a TLS ClientCertificate on a per-MASA basis, or to use no
client certificate. Registrars SHOULD also permit an HTTP Basic and client certificate. Registrars SHOULD also permit an HTTP Basic and
Digest authentication to be configured. Digest authentication to be configured.
The authentication of the BRSKI-MASA connection does not change the The authentication of the BRSKI-MASA connection does not change the
voucher-request process, as voucher-requests are already signed by voucher-request process, as voucher-requests are already signed by
the registrar. Instead, this authentication provides access control the registrar. Instead, this authentication provides access control
to the audit log. to the audit-log as described in Section 5.8.
Implementors are advised that contacting the MASA is to establish a Implementors are advised that contacting the MASA is to establish a
secured REST connection with a web service and that there are a secured REST connection with a web service and that there are a
number of authentication models being explored within the industry. number of authentication models being explored within the industry.
Registrars are RECOMMENDED to fail gracefully and generate useful Registrars are RECOMMENDED to fail gracefully and generate useful
administrative notifications or logs in the advent of unexpected HTTP administrative notifications or logs in the advent of unexpected HTTP
401 (Unauthorized) responses from the MASA. 401 (Unauthorized) responses from the MASA.
5.4.1. MASA authentication of customer Registrar 5.4.1. MASA authentication of customer Registrar
skipping to change at page 43, line 22 skipping to change at page 43, line 17
A third (and simplest, but least flexible) mechanism would be for the A third (and simplest, but least flexible) mechanism would be for the
MASA to simply store the Registrar's certificate pinned in a MASA to simply store the Registrar's certificate pinned in a
database. database.
A MASA without any supply chain integration can simply accept A MASA without any supply chain integration can simply accept
Registrars without any authentication, or can accept them on a blind Registrars without any authentication, or can accept them on a blind
Trust-on-First-Use basis as described in Section 7.4.2. Trust-on-First-Use basis as described in Section 7.4.2.
This document does not make a specific recommendation as there is This document does not make a specific recommendation as there is
likely different trade offs in different environments and product likely different tradeoffs in different environments and product
values. Even within the ANIMA ACP applicability, there is a values. Even within the ANIMA ACP applicability, there is a
significant difference between supply chain logistics for $100 CPE significant difference between supply chain logistics for $100 CPE
devices and $100,000 core routers. devices and $100,000 core routers.
5.5. Registrar Requests Voucher from MASA 5.5. Registrar Requests Voucher from MASA
When a registrar receives a pledge voucher-request it in turn submits When a registrar receives a pledge voucher-request it in turn submits
a registrar voucher-request to the MASA service via an HTTPS a registrar voucher-request to the MASA service via an HTTPS
interface ([RFC7231]). interface ([RFC7231]).
skipping to change at page 44, line 23 skipping to change at page 44, line 19
serial-number: The serial number of the pledge the registrar would serial-number: The serial number of the pledge the registrar would
like a voucher for. The registrar determines this value by like a voucher for. The registrar determines this value by
parsing the authenticated pledge IDevID certificate. See parsing the authenticated pledge IDevID certificate. See
Section 2.3. The registrar MUST verify that the serial number Section 2.3. The registrar MUST verify that the serial number
field it parsed matches the serial number field the pledge field it parsed matches the serial number field the pledge
provided in its voucher-request. This provides a sanity check provided in its voucher-request. This provides a sanity check
useful for detecting error conditions and logging. The registrar useful for detecting error conditions and logging. The registrar
MUST NOT simply copy the serial number field from a pledge voucher MUST NOT simply copy the serial number field from a pledge voucher
request as that field is claimed but not certified. request as that field is claimed but not certified.
idevid-issuer: The Issuer value from the value from the pledge idevid-issuer: The Issuer value from the pledge IDevID certificate
IDevID certificate is included to ensure a uniqueness of the is included to ensure a uniqueness of the serial-number. In the
serial-number. In the case of nonceless (offline) voucher- case of nonceless (offline) voucher-request, then an appropriate
request, then an appropriate value needs to be configured from the value needs to be configured from the same out-of-band source as
same out-of-band source as the serial-number. the serial-number.
prior-signed-voucher-request: The signed pledge voucher-request prior-signed-voucher-request: The signed pledge voucher-request
SHOULD be included in the registrar voucher-request. The entire SHOULD be included in the registrar voucher-request. The entire
CMS signed structure is to be included, base64 encoded for CMS signed structure is to be included, base64 encoded for
transport in the JSON structure. transport in the JSON structure.
A nonceless registrar voucher-request MAY be submitted to the MASA. A nonceless registrar voucher-request MAY be submitted to the MASA.
Doing so allows the registrar to request a voucher when the pledge is Doing so allows the registrar to request a voucher when the pledge is
offline, or when the registrar anticipates not being able to connect offline, or when the registrar anticipates not being able to connect
to the MASA while the pledge is being deployed. Some use cases to the MASA while the pledge is being deployed. Some use cases
require the registrar to learn the appropriate IDevID SerialNumber require the registrar to learn the appropriate IDevID SerialNumber
field and appropriate 'Accept header field' values from the physical field and appropriate 'Accept header field' values from the physical
device labeling or from the sales channel (out-of-scope for this device labeling or from the sales channel (out-of-scope for this
document). document).
All other fields MAY be omitted in the registrar voucher-request. All other fields MAY be omitted in the registrar voucher-request.
The "proximity-registrar-cert" field MUST NOT be present in the
registrar voucher-request.
Example JSON payloads of registrar voucher-requests are in Example JSON payloads of registrar voucher-requests are in
Section 3.3 Examples 2 through 4. Section 3.3 Examples 2 through 4.
The MASA verifies that the registrar voucher-request is internally The MASA verifies that the registrar voucher-request is internally
consistent but does not necessarily authenticate the registrar consistent but does not necessarily authenticate the registrar
certificate since the registrar is not known to the MASA in advance. certificate since the registrar MAY not be known to the MASA in
The MASA performs the actions and validation checks described in the advance. The MASA performs the actions and validation checks
following sub-sections before issuing a voucher. described in the following sub-sections before issuing a voucher.
5.5.1. MASA renewal of expired vouchers 5.5.1. MASA renewal of expired vouchers
As described in [RFC8366] vouchers are normally short lived to avoid As described in [RFC8366] vouchers are normally short lived to avoid
revocation issues. If the request is for a previous (expired) revocation issues. If the request is for a previous (expired)
voucher using the same registrar then the request for a renewed voucher using the same registrar (that is, a Registrar with the same
voucher SHOULD be automatically authorized. The MASA has sufficient Domain CA) then the request for a renewed voucher SHOULD be
information to determine this by examining the request, the registrar automatically authorized. The MASA has sufficient information to
authentication, and the existing audit log. The issuance of a determine this by examining the request, the registrar
authentication, and the existing audit-log. The issuance of a
renewed voucher is logged as detailed in Section 5.6. renewed voucher is logged as detailed in Section 5.6.
To inform the MASA that existing vouchers are not to be renewed one To inform the MASA that existing vouchers are not to be renewed one
can update or revoke the registrar credentials used to authorize the can update or revoke the registrar credentials used to authorize the
request (see Section 5.5.3 and Section 5.5.4). More flexible methods request (see Section 5.5.4 and Section 5.5.3). More flexible methods
will likely involve sales channel integration and authorizations will likely involve sales channel integration and authorizations
(details are out-of-scope of this document). (details are out-of-scope of this document).
5.5.2. MASA verification of voucher-request signature consistency 5.5.2. MASA pinning of registrar
The registrar's certificate chain is extracted from the signature
method. The entire registrar certificate chain was included in the
CMS structure, as specified in Section 5.5. This CA certificate will
be used to populate the "pinned-domain-cert" of the voucher being
issued.
If this domain CA is unknown to the MASA, then it is to be considered
a temporary trust anchor for the rest of the steps in this section.
The intention is not to authenticate the message as having come from
a fully validated origin, but to establish the consistency of the
domain PKI.
5.5.3. MASA checking of voucher request signature
As described in Section 5.5.2, the MASA has extracted Registrar's
domain CA. This is used to validate the CMS signature ([RFC5652]) on
the voucher-request.
Normal PKIX revocation checking is assumed during voucher-request
signature validation. This CA certificate MAY have Certificate
Revocation List distribution points, or Online Certificate Status
Protocol (OCSP) information ([RFC6960]). If they are present, the
MASA MUST be able to reach the relevant servers belonging to the
Registrar's domain CA to perform the revocation checks.
The use of OCSP Stapling is preferred.
5.5.4. MASA verification of domain registrar
The MASA MUST verify that the registrar voucher-request is signed by The MASA MUST verify that the registrar voucher-request is signed by
a registrar. This is confirmed by verifying that the id-kp-cmcRA a registrar. This is confirmed by verifying that the id-kp-cmcRA
extended key usage extension field (as detailed in EST RFC7030 extended key usage extension field (as detailed in EST RFC7030
section 3.6.1) exists in the certificate of the entity that signed section 3.6.1) exists in the certificate of the entity that signed
the registrar voucher-request. This verification is only a the registrar voucher-request. This verification is only a
consistency check that the unauthenticated domain CA intended the consistency check that the unauthenticated domain CA intended the
voucher-request signer to be a registrar. Performing this check voucher-request signer to be a registrar. Performing this check
provides value to the domain PKI by assuring the domain administrator provides value to the domain PKI by assuring the domain administrator
that the MASA service will only respect claims from authorized that the MASA service will only respect claims from authorized
Registration Authorities of the domain. Registration Authorities of the domain.
5.5.3. MASA authentication of registrar (certificate) Even when a domain CA is authenticated to the MASA, and there is
strong sales channel integration to understand who the legitimate
owner is, the above cmcRC check prevents arbitrary End-Entity
certificates (such as an LDevID certificate) from having vouchers
issued against them.
Other cases of inappropriate voucher issuance are detected by
examination of the audit log.
If a nonceless voucher-request is submitted the MASA MUST If a nonceless voucher-request is submitted the MASA MUST
authenticate the registrar as described in either EST [RFC7030] authenticate the registrar as described in either EST [RFC7030]
section 3.2.3, section 3.3.2, or by validating the registrar's section 3.2.3, section 3.3.2, or by validating the registrar's
certificate used to sign the registrar voucher-request. Any of these certificate used to sign the registrar voucher-request using a
methods reduce the risk of DDoS attacks and provide an authenticated configured trust anchor. Any of these methods reduce the risk of
identity as an input to sales channel integration and authorizations DDoS attacks and provide an authenticated identity as an input to
(details are out-of-scope of this document). sales channel integration and authorizations (details are out-of-
scope of this document).
In the nonced case, validation of the Registrar's identity (via TLS In the nonced case, validation of the Registrar's identity (via TLS
Client Certificate or HTTP authentication) MAY be omitted if the Client Certificate or HTTP authentication) MAY be omitted if the
device policy is to accept audit-only vouchers. device policy is to accept audit-only vouchers.
5.5.4. MASA revocation checking of registrar (certificate)
As noted in Section 5.5.3 the MASA performs registrar authentication
in a subset of situations (e.g. nonceless voucher requests). Normal
PKIX revocation checking is assumed during either EST client
authentication or voucher-request signature validation. Similarly,
as noted in Section 5.5.2, the MASA performs normal PKIX revocation
checking during signature consistency checks (a signature by a
registrar certificate that has been revoked is an inconsistency).
5.5.5. MASA verification of pledge prior-signed-voucher-request 5.5.5. MASA verification of pledge prior-signed-voucher-request
The MASA MAY verify that the registrar voucher-request includes the The MASA MAY verify that the registrar voucher-request includes the
'prior-signed-voucher-request' field. If so the prior-signed- 'prior-signed-voucher-request' field. If so the prior-signed-
voucher-request MUST include a 'proximity-registrar-cert' that is voucher-request MUST include a 'proximity-registrar-cert' that is
consistent with the certificate used to sign the registrar voucher- consistent with to the certificate used to sign the registrar
request. Additionally the voucher-request serial-number leaf MUST voucher-request. Additionally the voucher-request serial-number leaf
match the pledge serial-number that the MASA extracts from the MUST match the pledge serial-number that the MASA extracts from the
signing certificate of the prior-signed-voucher-request. signing certificate of the prior-signed-voucher-request. The
consistency check described above is checking that the 'proximity-
registrar-cert' SPKI fingerprint exists within the registrar voucher-
request CMS signature's certificate chain. This is substantially the
same as the pin validation described in in [RFC7469] section 2.6,
paragraph three.
If these checks succeed the MASA updates the voucher and audit log If these checks succeed the MASA updates the voucher and audit-log
assertion leafs with the "proximity" assertion. assertion leafs with the "proximity" assertion.
5.5.6. MASA pinning of registrar 5.5.6. MASA nonce handling
The registrar's certificate chain is extracted from the signature
method. The chain includes the domain CA certificate as specified in
Section 5.5.2. This certificate is used to populate the "pinned-
domain-cert" of the voucher being issued. The domainID (e.g., hash
of the root public key) is determined from the pinned-domain-cert and
is used to update the audit log.
5.5.7. MASA nonce handling
The MASA does not verify the nonce itself. If the registrar voucher- The MASA does not verify the nonce itself. If the registrar voucher-
request contains a nonce, and the prior-signed-voucher-request request contains a nonce, and the prior-signed-voucher-request
exists, then the MASA MUST verify that the nonce is consistent. exists, then the MASA MUST verify that the nonce is consistent.
(Recall from above that the voucher-request might not contain a (Recall from above that the voucher-request might not contain a
nonce, see Section 5.5 and Section 5.5.3). nonce, see Section 5.5 and Section 5.5.4).
The MASA populates the audit-log with the nonce that was verified. The MASA populates the audit-log with the nonce that was verified.
If a nonceless voucher is issued, then the audit log is to be If a nonceless voucher is issued, then the audit-log is to be
populated with the JSON value "null". populated with the JSON value "null".
5.6. MASA and Registrar Voucher Response 5.6. MASA and Registrar Voucher Response
The MASA voucher response to the registrar is forwarded without The MASA voucher response to the registrar is forwarded without
changes to the pledge; therefore this section applies to both the changes to the pledge; therefore this section applies to both the
MASA and the registrar. The HTTP signaling described applies to both MASA and the registrar. The HTTP signaling described applies to both
the MASA and registrar responses. the MASA and registrar responses.
When a voucher request arrives at the registrar, if it has a cached When a voucher request arrives at the registrar, if it has a cached
response from the MASA for the corresponding registrar voucher- response from the MASA for the corresponding registrar voucher-
request, that cached response can be used according to local policy; request, that cached response can be used according to local policy;
otherwise the registrar constructs a new registrar voucher-request otherwise the registrar constructs a new registrar voucher-request
and sends it to the MASA. and sends it to the MASA.
Registrar evaluation of the voucher itself is purely for transparency Registrar evaluation of the voucher itself is purely for transparency
and audit purposes to further inform log verification (see and audit purposes to further inform log verification (see
Section 5.8.2) and therefore a registrar could accept future voucher Section 5.8.3) and therefore a registrar could accept future voucher
formats that are opaque to the registrar. formats that are opaque to the registrar.
If the voucher-request is successful, the server (MASA responding to If the voucher-request is successful, the server (MASA responding to
registrar or registrar responding to pledge) response MUST contain an registrar or registrar responding to pledge) response MUST contain an
HTTP 200 response code. The server MUST answer with a suitable 4xx HTTP 200 response code. The server MUST answer with a suitable 4xx
or 5xx HTTP [RFC7230] error code when a problem occurs. In this or 5xx HTTP [RFC7230] error code when a problem occurs. In this
case, the response data from the MASA MUST be a plaintext human- case, the response data from the MASA MUST be a plaintext human-
readable (ASCII, English) error message containing explanatory readable (UTF-8) error message containing explanatory information
information describing why the request was rejected. describing why the request was rejected.
The registrar MAY respond with an HTTP 202 ("the request has been The registrar MAY respond with an HTTP 202 ("the request has been
accepted for processing, but the processing has not been completed") accepted for processing, but the processing has not been completed")
as described in EST [RFC7030] section 4.2.3 wherein the client "MUST as described in EST [RFC7030] section 4.2.3 wherein the client "MUST
wait at least the specified 'Retry-After' time before repeating the wait at least the specified 'Retry-After' time before repeating the
same request". (see [RFC7231] section 6.6.4) The pledge is same request". (see [RFC7231] section 6.6.4) The pledge is
RECOMMENDED to provide local feedback (blinked LED etc) during this RECOMMENDED to provide local feedback (blinked LED etc) during this
wait cycle if mechanisms for this are available. To prevent an wait cycle if mechanisms for this are available. To prevent an
attacker registrar from significantly delaying bootstrapping the attacker registrar from significantly delaying bootstrapping the
pledge MUST limit the 'Retry-After' time to 60 seconds. Ideally the pledge MUST limit the 'Retry-After' time to 60 seconds. Ideally the
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voucher that cannot be overridden. voucher that cannot be overridden.
A 404 (Not Found) response is appropriate when the request is for a A 404 (Not Found) response is appropriate when the request is for a
device that is not known to the MASA. device that is not known to the MASA.
A 406 (Not Acceptable) response is appropriate if a voucher of the A 406 (Not Acceptable) response is appropriate if a voucher of the
desired type or using the desired algorithms (as indicated by the desired type or using the desired algorithms (as indicated by the
Accept: header fields, and algorithms used in the signature) cannot Accept: header fields, and algorithms used in the signature) cannot
be issued such as because the MASA knows the pledge cannot process be issued such as because the MASA knows the pledge cannot process
that type. The registrar SHOULD use this response if it determines that type. The registrar SHOULD use this response if it determines
the pledge is unacceptable due to inventory control, MASA audit logs, the pledge is unacceptable due to inventory control, MASA audit-logs,
or any other reason. or any other reason.
A 415 (Unsupported Media Type) response is appropriate for a request A 415 (Unsupported Media Type) response is appropriate for a request
that has a voucher-request or Accept: value that is not understood. that has a voucher-request or Accept: value that is not understood.
The voucher response format is as indicated in the submitted Accept The voucher response format is as indicated in the submitted Accept
header fields or based on the MASA's prior understanding of proper header fields or based on the MASA's prior understanding of proper
format for this Pledge. Only the [RFC8366] "application/voucher- format for this Pledge. Only the [RFC8366] "application/voucher-
cms+json" media type is defined at this time. The syntactic details cms+json" media type is defined at this time. The syntactic details
of vouchers are described in detail in [RFC8366]. Figure 14 shows a of vouchers are described in detail in [RFC8366]. Figure 14 shows a
skipping to change at page 48, line 43 skipping to change at page 49, line 21
"assertion": "logging", "assertion": "logging",
"pinned-domain-cert": "base64encodedvalue==", "pinned-domain-cert": "base64encodedvalue==",
"serial-number": "JADA123456789" "serial-number": "JADA123456789"
} }
} }
Figure 14: An example voucher Figure 14: An example voucher
The MASA populates the voucher fields as follows: The MASA populates the voucher fields as follows:
nonce: The nonce from the pledge if available. See Section 5.5.7. nonce: The nonce from the pledge if available. See Section 5.5.6.
assertion: The method used to verify the relationship between pledge assertion: The method used to verify the relationship between pledge
and registrar. See Section 5.5.5. and registrar. See Section 5.5.5.
pinned-domain-cert: The domain CA cert. See Section 5.5.6. This pinned-domain-cert: The domain CA cert. See Section 5.5.2. This
figure is illustrative, for an example, see Appendix D.2 figure is illustrative, for an example, see Appendix D.2
serial-number: The serial-number as provided in the voucher-request. serial-number: The serial-number as provided in the voucher-request.
Also see Section 5.5.5. Also see Section 5.5.5.
domain-cert-revocation-checks: Set as appropriate for the pledge's domain-cert-revocation-checks: Set as appropriate for the pledge's
capabilities and as documented in [RFC8366]. The MASA MAY set capabilities and as documented in [RFC8366]. The MASA MAY set
this field to 'false' since setting it to 'true' would require this field to 'false' since setting it to 'true' would require
that revocation information be available to the pledge and this that revocation information be available to the pledge and this
document does not make normative requirements for [RFC6961] or document does not make normative requirements for [RFC6961] or
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significant time in the future, but (c) will typically be short significant time in the future, but (c) will typically be short
(on the order of a week or less). The RECOMMENDED period for (a) (on the order of a week or less). The RECOMMENDED period for (a)
is on the order of 20 minutes, so it will typically determine the is on the order of 20 minutes, so it will typically determine the
lifespan of the resulting voucher. 20 minutes is sufficient time lifespan of the resulting voucher. 20 minutes is sufficient time
to reach the post-provisional state in the pledge, at which point to reach the post-provisional state in the pledge, at which point
there is an established trust relationship between pledge and there is an established trust relationship between pledge and
registrar. The subsequent operations can take as long as required registrar. The subsequent operations can take as long as required
from that point onwards. The lifetime of the voucher has no from that point onwards. The lifetime of the voucher has no
impact on the lifespan of the ownership relationship. impact on the lifespan of the ownership relationship.
Whenever a voucher is issued the MASA MUST update the audit log Whenever a voucher is issued the MASA MUST update the audit-log
appropriately. The internal state requirements to maintain the audit sufficiently to generate the response as described in Section 5.8.1.
log are out-of-scope. See Section 5.8.1 for a discussion of The internal state requirements to maintain the audit-log are out-of-
reporting the log to a registrar. scope.
5.6.1. Pledge voucher verification 5.6.1. Pledge voucher verification
The pledge MUST verify the voucher signature using the manufacturer The pledge MUST verify the voucher signature using the manufacturer
installed trust anchor(s) associated with the manufacturer's MASA installed trust anchor(s) associated with the manufacturer's MASA
(this is likely included in the pledge's firmware). Management of (this is likely included in the pledge's firmware). Management of
the manufacturer installed trust anchor(s) is out-of-scope of this the manufacturer installed trust anchor(s) is out-of-scope of this
document; this protocol does not update these trust anchor(s). document; this protocol does not update these trust anchor(s).
The pledge MUST verify the serial-number field of the signed voucher The pledge MUST verify the serial-number field of the signed voucher
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Figure 15: Example Status Telemetry Figure 15: Example Status Telemetry
The server SHOULD respond with an HTTP 200 but MAY simply fail with The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error. The client ignores any response. Within the an HTTP 404 error. The client ignores any response. Within the
server logs the server SHOULD capture this telemetry information. server logs the server SHOULD capture this telemetry information.
Additional standard JSON fields in this POST MAY be added, see Additional standard JSON fields in this POST MAY be added, see
Section 8.4. A server that sees unknown fields should log them, but Section 8.4. A server that sees unknown fields should log them, but
otherwise ignore them. otherwise ignore them.
5.8. Registrar audit log request 5.8. Registrar audit-log request
After receiving the pledge status telemetry Section 5.7, the After receiving the pledge status telemetry Section 5.7, the
registrar SHOULD request the MASA audit log from the MASA service. registrar SHOULD request the MASA audit-log from the MASA service.
This is done with an HTTP POST using the operation path value of This is done with an HTTP POST using the operation path value of
"/.well-known/est/requestauditlog". "/.well-known/est/requestauditlog".
The registrar SHOULD HTTP POST the same registrar voucher-request as The registrar SHOULD HTTP POST the same registrar voucher-request as
it did when requesting a voucher (using the same Content-Type). It it did when requesting a voucher (using the same Content-Type). It
is posted to the /requestauditlog URI instead. The "idevid-issuer" is posted to the /requestauditlog URI instead. The "idevid-issuer"
and "serial-number" informs the MASA which log is requested so the and "serial-number" informs the MASA which log is requested so the
appropriate log can be prepared for the response. Using the same appropriate log can be prepared for the response. Using the same
media type and message minimizes cryptographic and message operations media type and message minimizes cryptographic and message operations
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as to avoid an extra crypto validation. as to avoid an extra crypto validation.
A registrar MAY request logs at future times. If the registrar A registrar MAY request logs at future times. If the registrar
generates a new request then the MASA is forced to perform the generates a new request then the MASA is forced to perform the
additional cryptographic operations to verify the new request. additional cryptographic operations to verify the new request.
A MASA that receives a request for a device that does not exist, or A MASA that receives a request for a device that does not exist, or
for which the requesting owner was never an owner returns an HTTP 404 for which the requesting owner was never an owner returns an HTTP 404
("Not found") code. ("Not found") code.
Rather than returning the audit log as a response to the POST (with a It is reasonable for a Registrar, that the MASA does not believe to
be the current owner, to request the audit-log. There are probably
reasons for this which are hard to predict in advance. For instance,
such a registrar may not be aware that the device has been resold; it
may be that the device has been resold inappropriately, and this is
how the original owner will learn of the occurance. It is also
possible that the device legitimately spends time in two different
networks.
Rather than returning the audit-log as a response to the POST (with a
return code 200), the MASA MAY instead return a 201 ("Created") return code 200), the MASA MAY instead return a 201 ("Created")
response ([RFC7231] sections 6.3.2 and 7.1) containing a URL to the response ([RFC7231] sections 6.3.2 and 7.1), with the URL to the
prepared (and idempotent, therefore cachable) audit response. prepared (and idempotent, therefore cachable) audit response in the
Location: header field.
In order to avoid enumeration of device audit logs, MASA that return In order to avoid enumeration of device audit-logs, MASA that return
URLs SHOULD take care to make the returned URL unguessable. URLs SHOULD take care to make the returned URL unguessable.
[W3C.WD-capability-urls-20140218] provides very good additional [W3C.WD-capability-urls-20140218] provides very good additional
guidance. For instance, rather than returning URLs containing a guidance. For instance, rather than returning URLs containing a
database number such as https://example.com/auditlog/1234 or the EUI database number such as https://example.com/auditlog/1234 or the EUI
of the device such https://example.com/auditlog/10-00-00-11-22-33, of the device such https://example.com/auditlog/10-00-00-11-22-33,
the MASA SHOULD return a randomly generated value (a "slug" in web the MASA SHOULD return a randomly generated value (a "slug" in web
parlance). The value is used to find the relevant database entry. parlance). The value is used to find the relevant database entry.
A MASA that returns a code 200 MAY also include a Location: header A MASA that returns a code 200 MAY also include a Location: header
for future reference by the registrar. for future reference by the registrar.
5.8.1. MASA audit log response 5.8.1. MASA audit log response
A log data file is returned consisting of all log entries associated A log data file is returned consisting of all log entries associated
with the device selected by the IDevID presented in the request. The with the device selected by the IDevID presented in the request. The
audit log may be abridged by removal of old or repeated values as audit log may be abridged by removal of old or repeated values as
explained below. The returned data is in JSON format ([RFC7159]), explained below. The returned data is in JSON format ([RFC8259]),
and the Content-Type SHOULD be "application/json". For example: and the Content-Type SHOULD be "application/json". For example:
{ {
"version":"1", "version":"1",
"events":[ "events":[
{ {
"date":"<date/time of the entry>", "date":"<date/time of the entry>",
"domainID":"<domainID extracted from voucher-request>", "domainID":"<domainID extracted from voucher-request>",
"nonce":"<any nonce if supplied (or NULL)>", "nonce":"<any nonce if supplied (or NULL)>",
"assertion":"<the value from the voucher assertion leaf>", "assertion":"<the value from the voucher assertion leaf>",
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], ],
"truncation": { "truncation": {
"nonced duplicates": "<total number of entries truncated>", "nonced duplicates": "<total number of entries truncated>",
"nonceless duplicates": "<total number of entries truncated>", "nonceless duplicates": "<total number of entries truncated>",
"arbitrary": "<number of domainID entries removed entirely>" "arbitrary": "<number of domainID entries removed entirely>"
} }
} }
Figure 16: Example of audit-log response Figure 16: Example of audit-log response
The domainID is a binary value calculated SubjectKeyIdentifier
according to Section 5.8.2. It is encoded once in base64 in order to
be transported in this JSON container.
Distribution of a large log is less than ideal. This structure can Distribution of a large log is less than ideal. This structure can
be optimized as follows: Nonced or Nonceless entries for the same be optimized as follows: Nonced or Nonceless entries for the same
domainID MAY be abridged from the log leaving only the single most domainID MAY be abridged from the log leaving only the single most
recent nonced or nonceless entry for that domainID. In the case of recent nonced or nonceless entry for that domainID. In the case of
truncation the 'event' truncation value SHOULD contain a count of the truncation the 'event' truncation value SHOULD contain a count of the
number of events for this domainID that were omitted. The log SHOULD number of events for this domainID that were omitted. The log SHOULD
NOT be further reduced but there could exist operational situation NOT be further reduced but there could exist operational situation
where maintaining the full log is not possible. In such situations where maintaining the full log is not possible. In such situations
the log MAY be arbitrarily abridged for length, with the number of the log MAY be arbitrarily abridged for length, with the number of
removed entries indicated as 'arbitrary'. removed entries indicated as 'arbitrary'.
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This document specifies a simple log format as provided by the MASA This document specifies a simple log format as provided by the MASA
service to the registrar. This format could be improved by service to the registrar. This format could be improved by
distributed consensus technologies that integrate vouchers with distributed consensus technologies that integrate vouchers with
technologies such as block-chain or hash trees or optimized logging technologies such as block-chain or hash trees or optimized logging
approaches. Doing so is out of the scope of this document but is an approaches. Doing so is out of the scope of this document but is an
anticipated improvement for future work. As such, the registrar anticipated improvement for future work. As such, the registrar
SHOULD anticipate new kinds of responses, and SHOULD provide operator SHOULD anticipate new kinds of responses, and SHOULD provide operator
controls to indicate how to process unknown responses. controls to indicate how to process unknown responses.
5.8.2. Registrar audit log verification 5.8.2. Calculation of domainID
The domainID is a binary value (a BIT STRING) that uniquely
identifies a Registrar by the "pinned-domain-cert"
If the "pinned-domain-cert" certificate includes the
SubjectKeyIdentifier (Section 4.2.1.2 [RFC5280]), then it is to be
used as the domainID. If not, then it is the SPKI Fingerprint as
described in [RFC7469] section 2.4 is to be used. This value needs
to be calculated by both MASA (to populate the audit-log), and by the
Registrar (to recognize itself).
[RFC5280] section 4.2.1.2 does not mandate that the
SubjectKeyIdentifier extension be present in non-CA certificates. It
is RECOMMENDED that Registrar certificates (even if self-signed),
always include the SubjectKeyIdentifier to be used as a domainID.
The domainID is determined from the certificate chain associated with
the pinned-domain-cert and is used to update the audit-log.
5.8.3. Registrar audit log verification
Each time the Manufacturer Authorized Signing Authority (MASA) issues Each time the Manufacturer Authorized Signing Authority (MASA) issues
a voucher, it appends details of the assignment to an internal audit a voucher, it appends details of the assignment to an internal audit
log for that device. The internal audit log is processed when log for that device. The internal audit log is processed when
responding to requests for details as described in Section 5.8. The responding to requests for details as described in Section 5.8. The
contents of the audit log can express a variety of trust levels, and contents of the audit log can express a variety of trust levels, and
this section explains what kind of trust a registrar can derive from this section explains what kind of trust a registrar can derive from
the entries. the entries.
While the audit log provides a list of vouchers that were issued by While the audit log provides a list of vouchers that were issued by
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registrar's that expected only new (not pre-owned) pledges. A registrar's that expected only new (not pre-owned) pledges. A
"logged" assertion informs the registrar that the prior vouchers "logged" assertion informs the registrar that the prior vouchers
were issued with minimal verification. A "proximity" assertion were issued with minimal verification. A "proximity" assertion
assures the registrar that the pledge was truly communicating with assures the registrar that the pledge was truly communicating with
the prior domain and thus provides assurance that the prior domain the prior domain and thus provides assurance that the prior domain
really has deployed the pledge. really has deployed the pledge.
A relatively simple policy is to white list known (internal or A relatively simple policy is to white list known (internal or
external) domainIDs. To require all vouchers to have a nonce. external) domainIDs. To require all vouchers to have a nonce.
Alternatively to require that all nonceless vouchers be from a subset Alternatively to require that all nonceless vouchers be from a subset
(e.g. only internal) domainIDs. If the policy is violated a simple (e.g. only internal) of domainIDs. If the policy is violated a
action is to revoke any locally issued credentials for the pledge in simple action is to revoke any locally issued credentials for the
question or to refuse to forward the voucher. The Registrar MUST pledge in question or to refuse to forward the voucher. The
then refuse any EST actions, and SHOULD inform a human via a log. A Registrar MUST then refuse any EST actions, and SHOULD inform a human
registrar MAY be configured to ignore (i.e. override the above via a log. A registrar MAY be configured to ignore (i.e. override
policy) the history of the device but it is RECOMMENDED that this the above policy) the history of the device but it is RECOMMENDED
only be configured if hardware assisted (i.e. TPM anchored) Network that this only be configured if hardware assisted (i.e. TPM
Endpoint Assessment (NEA) [RFC5209] is supported. anchored) Network Endpoint Assessment (NEA) [RFC5209] is supported.
5.9. EST Integration for PKI bootstrapping 5.9. EST Integration for PKI bootstrapping
The pledge SHOULD follow the BRSKI operations with EST enrollment The pledge SHOULD follow the BRSKI operations with EST enrollment
operations including "CA Certificates Request", "CSR Attributes" and operations including "CA Certificates Request", "CSR Attributes" and
"Client Certificate Request" or "Server-Side Key Generation", etc. "Client Certificate Request" or "Server-Side Key Generation", etc.
This is a relatively seamless integration since BRSKI REST calls This is a relatively seamless integration since BRSKI REST calls
provide an automated alternative to the manual bootstrapping method provide an automated alternative to the manual bootstrapping method
described in [RFC7030]. As noted above, use of HTTP 1.1 persistent described in [RFC7030]. As noted above, use of HTTP 1.1 persistent
connections simplifies the pledge state machine. connections simplifies the pledge state machine.
Although EST allows clients to obtain multiple certificates by Although EST allows clients to obtain multiple certificates by
sending multiple CSR requests; BRSKI does not support this mechanism sending multiple CSR requests, BRSKI does not support this mechanism
directly. This is because BRSKI pledges MUST use the CSR Attributes directly. This is because BRSKI pledges MUST use the CSR Attributes
request ([RFC7030] section 4.5). The registrar MUST validate the CSR request ([RFC7030] section 4.5). The registrar MUST validate the CSR
against the expected attributes. This implies that client requests against the expected attributes. This implies that client requests
will "look the same" and therefore result in a single logical will "look the same" and therefore result in a single logical
certificate being issued even if the client were to make multiple certificate being issued even if the client were to make multiple
requests. Registrars MAY contain more complex logic but doing so is requests. Registrars MAY contain more complex logic but doing so is
out-of-scope of this specification. BRSKI does not signal any out-of-scope of this specification. BRSKI does not signal any
enhancement or restriction to this capability. enhancement or restriction to this capability.
5.9.1. EST Distribution of CA Certificates 5.9.1. EST Distribution of CA Certificates
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created by a CA that is likely operated by a group that has no created by a CA that is likely operated by a group that has no
insight into different network services/protocols used. For example, insight into different network services/protocols used. For example,
the CA could even be outsourced. the CA could even be outsourced.
To alleviate these operational difficulties, the pledge MUST request To alleviate these operational difficulties, the pledge MUST request
the EST "CSR Attributes" from the EST server and the EST server needs the EST "CSR Attributes" from the EST server and the EST server needs
to be able to reply with the attributes necessary for use of the to be able to reply with the attributes necessary for use of the
certificate in its intended protocols/services. This approach allows certificate in its intended protocols/services. This approach allows
for minimal CA integrations and instead the local infrastructure (EST for minimal CA integrations and instead the local infrastructure (EST
server) informs the pledge of the proper fields to include in the server) informs the pledge of the proper fields to include in the
generated CSR. This approach is beneficial to automated generated CSR (such as rfc822Name). This approach is beneficial to
bootstrapping in the widest number of environments. automated bootstrapping in the widest number of environments.
If the hardwareModuleName in the X.509 IDevID is populated then it
SHOULD by default be propagated to the LDevID along with the
hwSerialNum. The EST server SHOULD support local policy concerning
this functionality.
In networks using the BRSKI enrolled certificate to authenticate the In networks using the BRSKI enrolled certificate to authenticate the
ACP (Autonomic Control Plane), the EST CSR attributes MUST include ACP (Autonomic Control Plane), the EST CSR attributes MUST include
the ACP Domain Information Fields defined in the ACP Domain Information Fields defined in
[I-D.ietf-anima-autonomic-control-plane] section 6.1.2. [I-D.ietf-anima-autonomic-control-plane] section 6.1.1.
The registrar MUST also confirm that the resulting CSR is formatted The registrar MUST also confirm that the resulting CSR is formatted
as indicated before forwarding the request to a CA. If the registrar as indicated before forwarding the request to a CA. If the registrar
is communicating with the CA using a protocol such as full CMC, which is communicating with the CA using a protocol such as full CMC, which
provides mechanisms to override the CSR attributes, then these provides mechanisms to override the CSR attributes, then these
mechanisms MAY be used even if the client ignores CSR Attribute mechanisms MAY be used even if the client ignores CSR Attribute
guidance. guidance.
5.9.3. EST Client Certificate Request 5.9.3. EST Client Certificate Request
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by the client. The MASA provides logs and status of credential by the client. The MASA provides logs and status of credential
enrollment. [RFC7030] assumes an end user and therefore does not enrollment. [RFC7030] assumes an end user and therefore does not
include a final success indication back to the server. This is include a final success indication back to the server. This is
insufficient for automated use cases. insufficient for automated use cases.
In order to communicate this indicator, the client HTTP POSTs the In order to communicate this indicator, the client HTTP POSTs the
following to the server at the new EST endpoint at "/.well-known/est/ following to the server at the new EST endpoint at "/.well-known/est/
enrollstatus". enrollstatus".
To indicate successful enrollment the client SHOULD first re- To indicate successful enrollment the client SHOULD first re-
negotiate the EST TLS session using the newly obtained credentials. establish the EST TLS session using the newly obtained credentials.
TLS 1.2 supports doing this in-band, but TLS 1.3 does not. The TLS 1.2 supports doing this in-band, but TLS 1.3 does not. The
client SHOULD therefore close the existing TLS connection, and start client SHOULD therefore close the existing TLS connection, and start
a new one. a new one.
In the case of a FAIL, the Reason string indicates why the most In the case of a FAIL, the Reason string indicates why the most
recent enrollment failed. The SubjectKeyIdentifier field MUST be recent enrollment failed. The SubjectKeyIdentifier field MUST be
included if the enrollment attempt was for a keypair that is locally included if the enrollment attempt was for a keypair that is locally
known to the client. If EST /serverkeygen was used and failed then known to the client. If EST /serverkeygen was used and failed then
the field is omitted from the status telemetry. the field is omitted from the status telemetry.
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bootstrapping of remote key infrastructures. Bootstrapping is bootstrapping of remote key infrastructures. Bootstrapping is
relevant for CoAP enrollment discussions as well. The definition of relevant for CoAP enrollment discussions as well. The definition of
EST and BRSKI over CoAP is not discussed within this document beyond EST and BRSKI over CoAP is not discussed within this document beyond
ensuring proxy support for CoAP operations. Instead it is ensuring proxy support for CoAP operations. Instead it is
anticipated that a definition of CoAP mappings will occur in anticipated that a definition of CoAP mappings will occur in
subsequent documents such as [I-D.ietf-ace-coap-est] and that CoAP subsequent documents such as [I-D.ietf-ace-coap-est] and that CoAP
mappings for BRSKI will be discussed either there or in future work. mappings for BRSKI will be discussed either there or in future work.
6. Clarification of transfer-encoding 6. Clarification of transfer-encoding
[RFC7030] defines it's endpoints to include a "Content-Transfer- [RFC7030] defines its endpoints to include a "Content-Transfer-
Encoding" heading, and the payloads to be [RFC4648] Base64 encoded Encoding" heading, and the payloads to be [RFC4648] Base64 encoded
DER. DER.
When used within BRSKI, the original RFC7030 EST endpoints remain When used within BRSKI, the original RFC7030 EST endpoints remain
Base64 encoded, but the new BRSKI end points which send and receive Base64 encoded, but the new BRSKI end points which send and receive
binary artifacts (specifically, /requestvoucher) are binary. That binary artifacts (specifically, /requestvoucher) are binary. That
is, no encoding is used. is, no encoding is used.
In the BRSKI context, the EST "Content-Transfer-Encoding" header In the BRSKI context, the EST "Content-Transfer-Encoding" header
field if present, SHOULD be ignored. This header field does not need field if present, SHOULD be ignored. This header field does not need
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devices are associated with which domains. These claims could be devices are associated with which domains. These claims could be
strengthened by using cryptographic log techniques to provide strengthened by using cryptographic log techniques to provide
append only, cryptographic assured, publicly auditable logs. append only, cryptographic assured, publicly auditable logs.
Vendor Service, Ownership Validation: This form of manufacturer Vendor Service, Ownership Validation: This form of manufacturer
service is trusted to accurately know which device is owned by service is trusted to accurately know which device is owned by
which domain. which domain.
7.2. Pledge security reductions 7.2. Pledge security reductions
The pledge can choose to accept vouchers using less secure methods. The following are a list of alternatives behaviours that the pledge
These methods enable offline and emergency (touch based) deployment can be programmed to implement. These behaviours are not mutually
use cases: exclusive, nor are they dependant upon other. Some of these methods
enable offline and emergency (touch based) deployment use cases.
Normative language is used as these behaviours are referenced in
later sections in a normative fashion.
1. The pledge MUST accept nonceless vouchers. This allows for a use 1. The pledge MUST accept nonceless vouchers. This allows for a use
case where the registrar can not connect to the MASA at the case where the registrar can not connect to the MASA at the
deployment time. Logging and validity periods address the deployment time. Logging and validity periods address the
security considerations of supporting these use cases. security considerations of supporting these use cases.
2. Many devices already support "trust on first use" for physical 2. Many devices already support "trust on first use" for physical
interfaces such as console ports. This document does not change interfaces such as console ports. This document does not change
that reality. Devices supporting this protocol MUST NOT support that reality. Devices supporting this protocol MUST NOT support
"trust on first use" on network interfaces. This is because "trust on first use" on network interfaces. This is because
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allows for unsecured imprint. allows for unsecured imprint.
4. A craft/serial console could include a command such as "est- 4. A craft/serial console could include a command such as "est-
enroll [2001:db8:0:1]:443" that begins the EST process from the enroll [2001:db8:0:1]:443" that begins the EST process from the
point after the voucher is validated. This process SHOULD point after the voucher is validated. This process SHOULD
include server certificate verification using an on-screen include server certificate verification using an on-screen
fingerprint. fingerprint.
It is RECOMMENDED that "trust on first use" or any method of skipping It is RECOMMENDED that "trust on first use" or any method of skipping
voucher validation (including use of craft serial console) only be voucher validation (including use of craft serial console) only be
available if hardware assisted Network Endpoint Assessment [RFC5209] available if hardware assisted Network Endpoint Assessment (NEA:
is supported. This recommendation ensures that domain network [RFC5209]) is supported. This recommendation ensures that domain
monitoring can detect inappropriate use of offline or emergency network monitoring can detect inappropriate use of offline or
deployment procedures when voucher-based bootstrapping is not used. emergency deployment procedures when voucher-based bootstrapping is
not used.
7.3. Registrar security reductions 7.3. Registrar security reductions
A registrar can choose to accept devices using less secure methods. A registrar can choose to accept devices using less secure methods.
These methods are acceptable when low security models are needed, as These methods are acceptable when low security models are needed, as
the security decisions are being made by the local administrator, but the security decisions are being made by the local administrator, but
they MUST NOT be the default behavior: they MUST NOT be the default behavior:
1. A registrar MAY choose to accept all devices, or all devices of a 1. A registrar MAY choose to accept all devices, or all devices of a
particular type, at the administrator's discretion. This could particular type, at the administrator's discretion. This could
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the need for ownership verification. the need for ownership verification.
A MASA that practices Trust-on-First-Use (TOFU) for Registrar A MASA that practices Trust-on-First-Use (TOFU) for Registrar
identity may wish to annotate the origin of the connection by IP identity may wish to annotate the origin of the connection by IP
address or netblock, and restrict future use of that identity from address or netblock, and restrict future use of that identity from
other locations. A MASA that does this SHOULD take care to not other locations. A MASA that does this SHOULD take care to not
create nuissance situations for itself when a customer has multiple create nuissance situations for itself when a customer has multiple
registrars, or uses outgoing IPv6 NAT44 connections that change registrars, or uses outgoing IPv6 NAT44 connections that change
frequently. frequently.
7.4.3. Updating or extending voucher trust anchors
A manufacturer could offer a management mechanism that allows the
list of voucher verification trust anchors to be extended.
[I-D.ietf-netconf-keystore] is one such interface that could be
implemented using YANG. Pretty much any configuration mechanism used
today could be extended to provide the needed additional update. A
manufacturer could even decide to install the domain CA trust anchors
received during the EST "cacerts" step as voucher verification
anchors. Some additional signals will be needed to clearly identify
which keys have voucher validation authority from among those signed
by the domain CA. This is future work.
With the above change to the list of anchors, vouchers can be issued
by an alternate MASA. This could be the previous owner (the seller),
or some other trusted third party who is mediating the sale. If it
was a third party, then the seller would need to have taken steps to
introduce the third party configuration to the device prior
disconnection. The third party (e.g. a wholesaler of used equipment)
could however use a mechanism described in Section 7.2 to take
control of the device after receiving it physically. This would
permit the third party to act as the MASA for future onboarding
actions. As the IDevID certificate probably can not be replaced, the
new owner's Registrar would have to support an override of the MASA
URL.
To be useful for resale or other transfers of ownership one of two
situations will need to occur. The simplest is that the device is
not put through any kind of factory default/reset before going
through onboarding again. Some other secure, physical signal would
be needed to initiate it. This is most suitable for redeploying a
device within the same Enterprise. This would entail having previous
configuration in the system until entirely replaced by the new owner,
and represents some level of risk.
The second mechanism is that there would need to be two levels of
factory reset. One would take the system back entirely to
manufacturer state, including removing any added trust anchors, and
the second (more commonly used) one would just restore the
configuration back to a known default without erasing trust anchors.
This weaker factor reset might leave valuable credentials on the
device and this may be unacceptable to some owners.
As a third option, the manufacturer's trust anchors could be entirely
overwitten with local trust anchors. A factory default would never
restore those anchors. This option comes with a lot of power, but
also a lot of responsability: if the new anchors are lost the
manufacturer may be unable to help.
8. IANA Considerations 8. IANA Considerations
This document requires the following IANA actions: This document requires the following IANA actions:
8.1. The IETF XML Registry 8.1. The IETF XML Registry
This document registers a URI in the "IETF XML Registry" [RFC3688]. This document registers a URI in the "IETF XML Registry" [RFC3688].
IANA has registered the following: IANA has registered the following:
URI: urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa URI: urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa
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Contact: IESG <iesg@ietf.org> Contact: IESG <iesg@ietf.org>
Description: The Bootstrapping Remote Secure Key Description: The Bootstrapping Remote Secure Key
Infrastructures Registrar Infrastructures Registrar
Reference: [This document] Reference: [This document]
8.6. MUD File Extension for the MASA 8.6. MUD File Extension for the MASA
The IANA is requested to list the name "masa" in the MUD extensions The IANA is requested to list the name "masa" in the MUD extensions
registry defined in [RFC8520]. Its use is documented in Appendix C. registry defined in [RFC8520]. Its use is documented in Appendix C.
9. Applicability to the Autonomic Control Plane 9. Applicability to the Autonomic Control Plane (ACP)
This document provides a solution to the requirements for secure This document provides a solution to the requirements for secure
bootstrap set out in Using an Autonomic Control Plane for Stable bootstrap set out in Using an Autonomic Control Plane for Stable
Connectivity of Network Operations, Administration, and Maintenance Connectivity of Network Operations, Administration, and Maintenance
[RFC8368], A Reference Model for Autonomic Networking [RFC8368], A Reference Model for Autonomic Networking
[I-D.ietf-anima-reference-model] and specifically the An Autonomic [I-D.ietf-anima-reference-model] and specifically the An Autonomic
Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane], section Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane], section
3.2 (Secure Bootstrap), and section 6.1 (ACP Domain, Certificate and 3.2 (Secure Bootstrap), and section 6.1 (ACP Domain, Certificate and
Network). Network).
The protocol described in this document has appeal in a number of The protocol described in this document has appeal in a number of
other non-ANIMA use cases. Such uses of the protocol will be other non-ANIMA use cases. Such uses of the protocol will be
deploying into other environments with different tradeoffs of deploying into other environments with different tradeoffs of
privacy, security, reliability and autonomy from manufacturers. As privacy, security, reliability and autonomy from manufacturers. As
such those use cases will need to provide their own applicability such those use cases will need to provide their own applicability
statements, and will need to address unique privacy and security statements, and will need to address unique privacy and security
considerations for the environments in which they are used. considerations for the environments in which they are used.
The autonomic control plane (ACP) that is bootstrapped by the BRSKI The autonomic control plane (ACP) that is bootstrapped by the BRSKI
protocol is typically used by medium to large Internet Service protocol is typically used in medium to large Internet Service
Provider organizations. Equivalent enterprises that has significant Provider organizations. Equivalent enterprises that has significant
layer-3 router connectivity also will find significant benefit, layer-3 router connectivity also will find significant benefit,
particularly if the Enterprise has many sites. (A network consisting particularly if the Enterprise has many sites. (A network consisting
of primarily layer-2 is not excluded, but the adjacencies that the of primarily layer-2 is not excluded, but the adjacencies that the
ACP will create and maintain will not reflect the topology until all ACP will create and maintain will not reflect the topology until all
devices participate in the ACP). devices participate in the ACP).
As specified in the ANIMA charter, this work "..focuses on As specified in the ANIMA charter, this work "..focuses on
professionally-managed networks." Such a network has an operator and professionally-managed networks." Such a network has an operator and
can do things like install, configure and operate the Registrar can do things like install, configure and operate the Registrar
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The BRSKI protocol is going into environments where there have The BRSKI protocol is going into environments where there have
already been quite a number of vendor proprietary management systems. already been quite a number of vendor proprietary management systems.
Those are not expected to go away quickly, but rather to leverage the Those are not expected to go away quickly, but rather to leverage the
secure credentials that are provisioned by BRSKI. The connectivity secure credentials that are provisioned by BRSKI. The connectivity
requirements of said management systems are provided by the ACP. requirements of said management systems are provided by the ACP.
10. Privacy Considerations 10. Privacy Considerations
10.1. MASA audit log 10.1. MASA audit log
The MASA audit log includes a hash of the domainID for each Registrar The MASA audit log includes the domainID for each domain a voucher
a voucher has been issued to. This information is closely related to has been issued to. This information is closely related to the
the actual domain identity. A MASA may need additional defenses actual domain identity. A MASA may need additional defenses against
against Denial of Service attacks (Section 11.1), and this may Denial of Service attacks (Section 11.1), and this may involve
involve collecting additional (unspecified here) information. This collecting additional (unspecified here) information. This could
could provide sufficient information for the MASA service to build a provide sufficient information for the MASA service to build a
detailed understanding the devices that have been provisioned within detailed understanding the devices that have been provisioned within
a domain. a domain.
There are a number of design choices that mitigate this risk. The There are a number of design choices that mitigate this risk. The
domain can maintain some privacy since it has not necessarily been domain can maintain some privacy since it has not necessarily been
authenticated and is not authoritatively bound to the supply chain. authenticated and is not authoritatively bound to the supply chain.
Additionally the domainID captures only the unauthenticated subject Additionally the domainID captures only the unauthenticated subject
key identifier of the domain. A privacy sensitive domain could key identifier of the domain. A privacy sensitive domain could
theoretically generate a new domainID for each device being deployed. theoretically generate a new domainID for each device being deployed.
Similarly a privacy sensitive domain would likely purchase devices Similarly a privacy sensitive domain would likely purchase devices
that support proximity assertions from a manufacturer that does not that support proximity assertions from a manufacturer that does not
require sales channel integrations. This would result in a require sales channel integrations. This would result in a
significant level of privacy while maintaining the security significant level of privacy while maintaining the security
characteristics provided by Registrar based audit log inspection. characteristics provided by Registrar based audit log inspection.
10.2. What BRSKI-MASA reveals to the manufacturer 10.2. What BRSKI-EST reveals to the registrar
During the provisional phase of the BRSKI-EST connection between the
Pledge and the Registrar, each party reveals its certificates to each
other. For the Pledge, this includes the serialNumber attribute, the
MASA URL, and the identity that signed the IDevID certificate.
TLS 1.2 reveals the certificate identities to on-path observers,
including the Join Proxy.
TLS 1.3 reveals the certificate identities only to the end parties,
but as the connection is provisional, an on-path attacker will see
the certificates. This includes not just malicious attackers, but
also Registrars that are visible to the Pledge, but which are not
part of the the intended domain.
10.3. What BRSKI-MASA reveals to the manufacturer
The so-called "call-home" mechanism that occurs as part of the BRSKI- The so-called "call-home" mechanism that occurs as part of the BRSKI-
MASA connection standardizes what has been deemed by some as a MASA connection standardizes what has been deemed by some as a
sinister mechanism for corporate oversight of individuals. sinister mechanism for corporate oversight of individuals.
([livingwithIoT] and [IoTstrangeThings] for a small sample). ([livingwithIoT] and [IoTstrangeThings] for a small sample).
As the Autonomic Control Plane (ACP) usage of BRSKI is not targeted As the Autonomic Control Plane (ACP) usage of BRSKI is not targeted
at individual usage of IoT devices, but rather at the Enterprise and at individual usage of IoT devices, but rather at the Enterprise and
ISP creation of networks in a zero-touch fashion, the "call-home" ISP creation of networks in a zero-touch fashion, the "call-home"
represents a different kind of concern. represents a different kind of concern.
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manufacturer: manufacturer:
o the identity of the device being enrolled (down to the serial- o the identity of the device being enrolled (down to the serial-
number!). number!).
o an identity of the domain owner in the form of the domain trust o an identity of the domain owner in the form of the domain trust
anchor. However, this is not a global PKI anchored name within anchor. However, this is not a global PKI anchored name within
the WebPKI, so this identity could be pseudonymous. If there is the WebPKI, so this identity could be pseudonymous. If there is
sales channel integration, then the MASA will have authenticated sales channel integration, then the MASA will have authenticated
the domain owner, either via pinned certificate, or perhaps the domain owner, either via pinned certificate, or perhaps
another HTTP authentication method, as per Section 5.5.3. another HTTP authentication method, as per Section 5.5.4.
o the time the device is activated, o the time the device is activated,
o the IP address of the domain Owner's Registrar. For ISPs and o the IP address of the domain Owner's Registrar. For ISPs and
Enterprises, the IP address provides very clear geolocation of the Enterprises, the IP address provides very clear geolocation of the
owner. No amount of IP address privacy extensions ([RFC4941]) can owner. No amount of IP address privacy extensions ([RFC4941]) can
do anything about this, as a simple whois lookup likely identifies do anything about this, as a simple whois lookup likely identifies
the ISP or Enterprise from the upper bits anyway. A passive the ISP or Enterprise from the upper bits anyway. A passive
attacker who observes the connection definitely may conclude that attacker who observes the connection definitely may conclude that
the given enterprise/ISP is a customer of the particular equipment the given enterprise/ISP is a customer of the particular equipment
vendor. The precise model that is being enrolled will remain vendor. The precise model that is being enrolled will remain
private. private.
Based upon the above information, the manufacturer is able to track a
specific device from pseudonymous domain identity to the next
pseudonymous domain identity. If there is sales-channel integration,
then the identities are not pseudonymous.
The above situation is to be distinguished from a residential/ The above situation is to be distinguished from a residential/
individual person who registers a device from a manufacturer: that an individual person who registers a device from a manufacturer: that an
enterprise/ISP purchases routing products is hardly worth mentioning. enterprise/ISP purchases routing products is hardly worth mentioning.
Deviations would, however, be notable.
Deviations from a historical trend or an establish baseline would,
however, be notable.
The situation is not improved by the enterprise/ISP using The situation is not improved by the enterprise/ISP using
anonymization services such as ToR [Dingledine2004], as a TLS 1.2 anonymization services such as ToR [Dingledine2004], as a TLS 1.2
connection will reveal the ClientCertificate used, clearly connection will reveal the ClientCertificate used, clearly
identifying the enterprise/ISP involved. TLS 1.3 is better in this identifying the enterprise/ISP involved. TLS 1.3 is better in this
regard, but an active attacker can still discover the parties regard, but an active attacker can still discover the parties
involved by performing a Man-In-The-Middle-Attack on the first involved by performing a Man-In-The-Middle-Attack on the first
attempt (breaking/killing it with a TCP RST), and then letting attempt (breaking/killing it with a TCP RST), and then letting
subsequent connection pass through. subsequent connection pass through.
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point of view as the same set of services (and the same set of point of view as the same set of services (and the same set of
Distributed Denial of Service mitigations) may be used. Distributed Denial of Service mitigations) may be used.
Unfortunately, as the BRSKI-MASA connections include TLS Unfortunately, as the BRSKI-MASA connections include TLS
ClientCertificate exchanges, this may easily be observed in TLS 1.2, ClientCertificate exchanges, this may easily be observed in TLS 1.2,
and a traffic analysis may reveal it even in TLS 1.3. This does not and a traffic analysis may reveal it even in TLS 1.3. This does not
make such a plan irrelevant. There may be other organizational make such a plan irrelevant. There may be other organizational
reasons to keep the marketing site (which is often subject to reasons to keep the marketing site (which is often subject to
frequent re-designs, outsourcing, etc.) separate from the MASA, which frequent re-designs, outsourcing, etc.) separate from the MASA, which
may need to operate reliably for decades. may need to operate reliably for decades.
10.3. Manufacturers and Used or Stolen Equipment 10.4. Manufacturers and Used or Stolen Equipment
As explained above, the manufacturer receives information each time As explained above, the manufacturer receives information each time
that a device which is in factory-default mode does a zero-touch that a device which is in factory-default mode does a zero-touch
bootstrap, and attempts to enroll into a domain owner's registrar. bootstrap, and attempts to enroll into a domain owner's registrar.
The manufacturer is therefore in a position to decline to issue a The manufacturer is therefore in a position to decline to issue a
voucher if it detects that the new owner is not the same as the voucher if it detects that the new owner is not the same as the
previous owner. previous owner.
1. This can be seen as a feature if the equipment is believed to 1. This can be seen as a feature if the equipment is believed to
skipping to change at page 69, line 34 skipping to change at page 72, line 13
ownership simply occurs. ownership simply occurs.
3. A manufacturer could however decide not to issue a new voucher in 3. A manufacturer could however decide not to issue a new voucher in
response to a transfer of ownership. This is essentially the response to a transfer of ownership. This is essentially the
same as the stolen case, with the manufacturer having decided same as the stolen case, with the manufacturer having decided
that the sale was not legitimate. that the sale was not legitimate.
4. There is a fourth case, if the manufacturer is providing 4. There is a fourth case, if the manufacturer is providing
protection against stolen devices. The manufacturer then has a protection against stolen devices. The manufacturer then has a
responsibility to protect the legitimate owner against fraudulent responsibility to protect the legitimate owner against fraudulent
claims that the equipment was stolen. Such a claim would cause claims that the equipment was stolen. In the absense of such
the manufacturer to refuse to issue a new voucher. Should the manufacturer protection, such a claim would cause the
device go through a deep factory reset (for instance, replacement manufacturer to refuse to issue a new voucher. Should the device
of a damaged main board component, the device would not go through a deep factory reset (for instance, replacement of a
bootstrap. damaged main board component, the device would not bootstrap.
5. Finally, there is a fifth case: the manufacturer has decided to 5. Finally, there is a fifth case: the manufacturer has decided to
end-of-line the device, or the owner has not paid a yearly end-of-line the device, or the owner has not paid a yearly
support amount, and the manufacturer refuses to issue new support amount, and the manufacturer refuses to issue new
vouchers at that point. This last case is not new to the vouchers at that point. This last case is not new to the
industry: many license systems are already deployed that have industry: many license systems are already deployed that have
significantly worse effect. significantly worse effect.
This section has outlined five situations in which a manufacturer This section has outlined five situations in which a manufacturer
could use the voucher system to enforce what are clearly license could use the voucher system to enforce what are clearly license
terms. A manufacturer that attempted to enforce license terms via terms. A manufacturer that attempted to enforce license terms via
vouchers would find it rather ineffective as the terms would only be vouchers would find it rather ineffective as the terms would only be
enforced when the device is enrolled, and this is not (to repeat), a enforced when the device is enrolled, and this is not (to repeat), a
daily or even monthly occurrence. daily or even monthly occurrence.
10.4. Manufacturers and Grey market equipment 10.5. Manufacturers and Grey market equipment
Manufacturers of devices often sell different products into different Manufacturers of devices often sell different products into different
regional markets. Which product is available in which market can be regional markets. Which product is available in which market can be
driven by price differentials, support issues (some markets may driven by price differentials, support issues (some markets may
require manuals and tech-support to be done in the local language), require manuals and tech-support to be done in the local language),
government export regulation (such as whether strong crypto is government export regulation (such as whether strong crypto is
permitted to be exported, or permitted to be used in a particular permitted to be exported, or permitted to be used in a particular
market). When an domain owner obtains a device from a different market). When an domain owner obtains a device from a different
market (they can be new) and transfers it to a different location, market (they can be new) and transfers it to a different location,
this is called a Grey Market. this is called a Grey Market.
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differentiation by reducing the cost of doing it. differentiation by reducing the cost of doing it.
An issue that manufacturers will need to deal with in the above An issue that manufacturers will need to deal with in the above
automated process is when a device is shipped to one country with one automated process is when a device is shipped to one country with one
set of rules (or laws or entitlements), but the domain registry is in set of rules (or laws or entitlements), but the domain registry is in
another one. Which rules apply is something will have to be worked another one. Which rules apply is something will have to be worked
out: the manufacturer could come to believe they are dealing with out: the manufacturer could come to believe they are dealing with
Grey market equipment, when it is simply dealing with a global Grey market equipment, when it is simply dealing with a global
enterprise. enterprise.
10.5. Some mitigations for meddling by manufacturers 10.6. Some mitigations for meddling by manufacturers
The most obvious mitigation is not to buy the product. Pick The most obvious mitigation is not to buy the product. Pick
manufacturers that are up-front about their policies, who do not manufacturers that are up-front about their policies, who do not
change them gratuitiously. change them gratuitiously.
A manufacturer could provide a mechanism to manage the trust anchors Section Section 7.4.3 describes some ways in which a manufacturer
and built-in certificates (IDevID) as an extension. This is a could provide a mechanism to manage the trust anchors and built-in
substantial amount of work, and may be an area for future certificates (IDevID) as an extension. There are a variety of
mechanism, and some may take a substantial amount of work to get
exactly correct. These mechanisms do not change the flow of the
protocol described here, but rather allow the starting trust
assumptions to be changed. This is an an area for future
standardization work. standardization work.
Replacement of the voucher validation anchors (usually pointing to Replacement of the voucher validation anchors (usually pointing to
the original manufacturer's MASA) with those of the new owner permits the original manufacturer's MASA) with those of the new owner permits
the new owner to issue vouchers to subsequent owners. This would be the new owner to issue vouchers to subsequent owners. This would be
done by having the selling (old) owner to run a MASA. done by having the selling (old) owner to run a MASA.
In order to automatically find the new MASA, the mechanism describe
in this document is to look for the MASA URL extension in the IDevID.
A new owner could override this in their Registrar, or the
manufacturer could provide a mechanism to update or replace the
IDevID prior to sale.
Once the voucher trust anchor and the IDevID is replaced, then the
device will no longer trust the manufacturer in any way. When a new
owner performs a bootstrap, the device will point to a MASA that has
been chosen, and will validate vouchers from this new entity.
The BRSKI protocol depends upon a trust anchor on the device and an The BRSKI protocol depends upon a trust anchor on the device and an
identity on the device. Management of these entities facilitates a identity on the device. Management of these entities facilitates a
few new operational modes without making any changes to the BRSKI few new operational modes without making any changes to the BRSKI
protocol. Those modes include: offline modes where the domain owner protocol. Those modes include: offline modes where the domain owner
operates an internal MASA for all devices, resell modes where the operates an internal MASA for all devices, resell modes where the
first domain owner becomes the MASA for the next (resold-to) domain first domain owner becomes the MASA for the next (resold-to) domain
owner, and services where an aggregator acquires a large variety of owner, and services where an aggregator acquires a large variety of
devices, and then acts as a pseudonymized MASA for a variety of devices, and then acts as a pseudonymized MASA for a variety of
devices from a variety of manufacturers. devices from a variety of manufacturers.
Some manufacturers may wish to consider replacement of the IDevID as Although replacement of the IDevID is not required for all modes
an indication that the device's warrantee is terminated. For others, described above, a manufacturers could support such a thing. Some
the privacy requirements of some deployments might consider this a may wish to consider replacement of the IDevID as an indication that
standard operating practice. the device's warrantee is terminated. For others, the privacy
requirements of some deployments might consider this a standard
operating practice.
As discussed at the end of Section 5.8.1, new work could be done to As discussed at the end of Section 5.8.1, new work could be done to
use a distributed consensus technology for the audit log. This would use a distributed consensus technology for the audit log. This would
permit the audit log to continue to be useful, even when there is a permit the audit log to continue to be useful, even when there is a
chain of MASA due to changes of ownership. chain of MASA due to changes of ownership.
11. Security Considerations 11. Security Considerations
This document details a protocol for bootstrapping that balances This document details a protocol for bootstrapping that balances
operational concerns against security concerns. As detailed in the operational concerns against security concerns. As detailed in the
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unbounded number of devices. Ensuring a registrar is representative unbounded number of devices. Ensuring a registrar is representative
of a valid manufacturer customer, even without validating ownership of a valid manufacturer customer, even without validating ownership
of specific pledge devices, helps to mitigate this. Pledge of specific pledge devices, helps to mitigate this. Pledge
signatures on the pledge voucher-request, as forwarded by the signatures on the pledge voucher-request, as forwarded by the
registrar in the prior-signed-voucher-request field of the registrar registrar in the prior-signed-voucher-request field of the registrar
voucher-request, significantly reduce this risk by ensuring the MASA voucher-request, significantly reduce this risk by ensuring the MASA
can confirm proximity between the pledge and the registrar making the can confirm proximity between the pledge and the registrar making the
request. Supply chain integration ("know your customer") is an request. Supply chain integration ("know your customer") is an
additional step that MASA providers and device vendors can explore. additional step that MASA providers and device vendors can explore.
11.2. Freshness in Voucher-Requests 11.2. Availability of good random numbers
Although the nonce used by the Pledge in the voucher-request does not
require a strong cryptographic randomness, the use of TLS in all of
the protocols in this document does.
In particular implementations should pay attention to the advance in
[RFC4086] section 3, particulary section 3.4. Devices which are
reset to factory default in order to perform a second bootstrap with
a new owner MUST NOT seed their random number generators in the same
way.
11.3. Freshness in Voucher-Requests
A concern has been raised that the pledge voucher-request should A concern has been raised that the pledge voucher-request should
contain some content (a nonce) provided by the registrar and/or MASA contain some content (a nonce) provided by the registrar and/or MASA
in order for those actors to verify that the pledge voucher-request in order for those actors to verify that the pledge voucher-request
is fresh. is fresh.
There are a number of operational problems with getting a nonce from There are a number of operational problems with getting a nonce from
the MASA to the pledge. It is somewhat easier to collect a random the MASA to the pledge. It is somewhat easier to collect a random
value from the registrar, but as the registrar is not yet vouched value from the registrar, but as the registrar is not yet vouched
for, such a registrar nonce has little value. There are privacy and for, such a registrar nonce has little value. There are privacy and
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but if this is a consideration the target network is RECOMMENDED to but if this is a consideration the target network is RECOMMENDED to
take the following steps: take the following steps:
o Ongoing network monitoring for unexpected bootstrapping attempts o Ongoing network monitoring for unexpected bootstrapping attempts
by pledges. by pledges.
o Retrieval and examination of MASA log information upon the o Retrieval and examination of MASA log information upon the
occurence of any such unexpected events. Rm will be listed in the occurence of any such unexpected events. Rm will be listed in the
logs along with nonce information for analysis. logs along with nonce information for analysis.
11.3. Trusting manufacturers 11.4. Trusting manufacturers
The BRSKI extensions to EST permit a new pledge to be completely The BRSKI extensions to EST permit a new pledge to be completely
configured with domain specific trust anchors. The link from built- configured with domain specific trust anchors. The link from built-
in manufacturer-provided trust anchors to domain-specific trust in manufacturer-provided trust anchors to domain-specific trust
anchors is mediated by the signed voucher artifact. anchors is mediated by the signed voucher artifact.
If the manufacturer's IDevID signing key is not properly validated, If the manufacturer's IDevID signing key is not properly validated,
then there is a risk that the network will accept a pledge that then there is a risk that the network will accept a pledge that
should not be a member of the network. As the address of the should not be a member of the network. As the address of the
manufacturer's MASA is provided in the IDevID using the extension manufacturer's MASA is provided in the IDevID using the extension
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device category (e.g, a light bulb, or a cable-modem) are signed device category (e.g, a light bulb, or a cable-modem) are signed
by an certificate authority specifically for this. This is done by an certificate authority specifically for this. This is done
by CableLabs today. It is used for authentication and by CableLabs today. It is used for authentication and
authorization as part of TR-79: [docsisroot] and [TR069]. authorization as part of TR-79: [docsisroot] and [TR069].
The existing WebPKI provides a reasonable anchor between manufacturer The existing WebPKI provides a reasonable anchor between manufacturer
name and public key. It authenticates the key. It does not provide name and public key. It authenticates the key. It does not provide
a reasonable authorization for the manufacturer, so it is not a reasonable authorization for the manufacturer, so it is not
directly useable on it's own. directly useable on it's own.
11.4. Manufacturer Maintenance of trust anchors 11.5. Manufacturer Maintenance of trust anchors
BRSKI depends upon the manufacturer building in trust anchors to the BRSKI depends upon the manufacturer building in trust anchors to the
pledge device. The voucher artifact which is signed by the MASA will pledge device. The voucher artifact which is signed by the MASA will
be validated by the pledge using that anchor. This implies that the be validated by the pledge using that anchor. This implies that the
manufacturer needs to maintain access to a signing key that the manufacturer needs to maintain access to a signing key that the
pledge can validate. pledge can validate.
The manufacturer will need to maintain the ability to make signatures The manufacturer will need to maintain the ability to make signatures
that can be validated for the lifetime that the device could be that can be validated for the lifetime that the device could be
onboarded. Whether this onboarding lifetime is less than the device onboarded. Whether this onboarding lifetime is less than the device
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or how strong the economic incentives are to maintain an appropriate or how strong the economic incentives are to maintain an appropriate
level of security. level of security.
This next section examines the risk due to a compromised MASA key. This next section examines the risk due to a compromised MASA key.
This is followed by examination of the risk of a compromised This is followed by examination of the risk of a compromised
manufacturer IDevID signing key. The third section sections below manufacturer IDevID signing key. The third section sections below
examines the situation where MASA web server itself is under attacker examines the situation where MASA web server itself is under attacker
control, but that the MASA signing key itself is safe in a not- control, but that the MASA signing key itself is safe in a not-
directly connected hardware module. directly connected hardware module.
11.4.1. Compromise of Manufacturer IDevID signing keys 11.5.1. Compromise of Manufacturer IDevID signing keys
An attacker that has access to the key that the manufacturer uses to An attacker that has access to the key that the manufacturer uses to
sign IDevID certificates can create counterfeit devices. Such sign IDevID certificates can create counterfeit devices. Such
devices can claim to be from a particular manufacturer, but be devices can claim to be from a particular manufacturer, but be
entirely different devices: Trojan horses in effect. entirely different devices: Trojan horses in effect.
As the attacker controls the MASA URL in the certificate, the As the attacker controls the MASA URL in the certificate, the
registrar can be convinced to talk to the attackers' MASA. The registrar can be convinced to talk to the attackers' MASA. The
Registrar does not need to be in any kind of promiscuous mode to be Registrar does not need to be in any kind of promiscuous mode to be
vulnerable. vulnerable.
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In addition to creating fake devices, the attacker may also be able In addition to creating fake devices, the attacker may also be able
to issue revocations for existing certificates if the IDevID to issue revocations for existing certificates if the IDevID
certificate process relies upon CRL lists that are distributed. certificate process relies upon CRL lists that are distributed.
There does not otherwise seem to be any risk from this compromise to There does not otherwise seem to be any risk from this compromise to
devices which are already deployed, or which are sitting locally in devices which are already deployed, or which are sitting locally in
boxes waiting for deployment (local spares). The issue is that boxes waiting for deployment (local spares). The issue is that
operators will be unable to trust devices which have been in an operators will be unable to trust devices which have been in an
uncontrolled warehouse as they do not know if those are real devices. uncontrolled warehouse as they do not know if those are real devices.
11.4.2. Compromise of MASA signing keys 11.5.2. Compromise of MASA signing keys
There are two periods of time in which to consider: when the MASA key There are two periods of time in which to consider: when the MASA key
has fallen into the hands of an attacker, and after the MASA has fallen into the hands of an attacker, and after the MASA
recognizes that the key has been compromised. recognizes that the key has been compromised.
11.4.2.1. Attacker opportunties with compromised MASA key 11.5.2.1. Attacker opportunties with compromised MASA key
An attacker that has access to the MASA signing key could create An attacker that has access to the MASA signing key could create
vouchers. These vouchers could be for existing deployed devices, or vouchers. These vouchers could be for existing deployed devices, or
for devices which are still in a warehouse. In order to exploit for devices which are still in a warehouse. In order to exploit
these vouchers two things need to occur: the device has to go through these vouchers two things need to occur: the device has to go through
a factory default boot cycle, and the registrar has to be convinced a factory default boot cycle, and the registrar has to be convinced
to contact the attacker's MASA. to contact the attacker's MASA.
If the attacker controls a Registrar which is visible to the device, If the attacker controls a Registrar which is visible to the device,
then there is no difficulty in delivery of the false voucher. A then there is no difficulty in delivery of the false voucher. A
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devices with low overall implementation quality, the end users might devices with low overall implementation quality, the end users might
be familiar with needing to reset the device regularly. be familiar with needing to reset the device regularly.
The authors are unable to come up with an attack scenario where a The authors are unable to come up with an attack scenario where a
compromised voucher signature enables an attacker to introduce a compromised voucher signature enables an attacker to introduce a
compromised pledge into an existing operator's network. This is the compromised pledge into an existing operator's network. This is the
case because the operator controls the communication between case because the operator controls the communication between
Registrar and MASA, and there is no opportunity to introduce the fake Registrar and MASA, and there is no opportunity to introduce the fake
voucher through that conduit. voucher through that conduit.
11.4.2.2. Risks after key compromise is known 11.5.2.2. Risks after key compromise is known
Once the operator of the MASA realizes that the voucher signing key Once the operator of the MASA realizes that the voucher signing key
has been compromised it has to do a few things. has been compromised it has to do a few things.
First, it MUST issue a firmware update to all devices that had that First, it MUST issue a firmware update to all devices that had that
key as a trust anchor, such that they will no longer trust vouchers key as a trust anchor, such that they will no longer trust vouchers
from that key. This will affect devices in the field which are from that key. This will affect devices in the field which are
operating, but those devices, being in operation, are not performing operating, but those devices, being in operation, are not performing
onboarding operations, so this is not a critical patch. onboarding operations, so this is not a critical patch.
skipping to change at page 79, line 23 skipping to change at page 82, line 12
voucher means that the window to deliver a fake voucher is very voucher means that the window to deliver a fake voucher is very
short. A nonceless, long-lived voucher would be the only option for short. A nonceless, long-lived voucher would be the only option for
the attacker, and devices in the warehouse would be vulnerable to the attacker, and devices in the warehouse would be vulnerable to
such a thing. such a thing.
A key operational recommendation is for manufacturers to sign A key operational recommendation is for manufacturers to sign
nonceless, long-lived vouchers with a different key that they sign nonceless, long-lived vouchers with a different key that they sign
short-lived vouchers. That key needs significantly better short-lived vouchers. That key needs significantly better
protection. If both keys come from a common trust-anchor (the protection. If both keys come from a common trust-anchor (the
manufacturer's CA), then a compromise of the manufacturer's CA would manufacturer's CA), then a compromise of the manufacturer's CA would
be a bigger problem. compromise both keys. Such a compromise of the manufacturer's CA
likely compromises all keys outlined in this section.
11.4.3. Compromise of MASA web service 11.5.3. Compromise of MASA web service
An attacker that takes over the MASA web service has a number of An attacker that takes over the MASA web service has a number of
attacks. The most obvious one is simply to take the database listing attacks. The most obvious one is simply to take the database listing
customers and devices and to sell this data to other attackers who customers and devices and to sell this data to other attackers who
will now know where to find potentially vulnerable devices. will now know where to find potentially vulnerable devices.
The second most obvious thing that the attacker can do is to kill the The second most obvious thing that the attacker can do is to kill the
service, or make it operate unreliably, making customers frustrated. service, or make it operate unreliably, making customers frustrated.
This could have a serious affect on ability to deploy new services by This could have a serious affect on ability to deploy new services by
customers, and would be a significant issue during disaster recovery. customers, and would be a significant issue during disaster recovery.
skipping to change at page 82, line 24 skipping to change at page 85, line 13
<https://www.rfc-editor.org/info/rfc5386>. <https://www.rfc-editor.org/info/rfc5386>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009, RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/info/rfc5652>. <https://www.rfc-editor.org/info/rfc5652>.
[RFC5660] Williams, N., "IPsec Channels: Connection Latching", [RFC5660] Williams, N., "IPsec Channels: Connection Latching",
RFC 5660, DOI 10.17487/RFC5660, October 2009, RFC 5660, DOI 10.17487/RFC5660, October 2009,
<https://www.rfc-editor.org/info/rfc5660>. <https://www.rfc-editor.org/info/rfc5660>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/info/rfc6066>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509 within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer (PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>. 2011, <https://www.rfc-editor.org/info/rfc6125>.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013, DOI 10.17487/RFC6762, February 2013,
<https://www.rfc-editor.org/info/rfc6762>. <https://www.rfc-editor.org/info/rfc6762>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>. <https://www.rfc-editor.org/info/rfc6763>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., [RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030, "Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013, DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>. <https://www.rfc-editor.org/info/rfc7030>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing", Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014, RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>. <https://www.rfc-editor.org/info/rfc7230>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231, Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014, DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>. <https://www.rfc-editor.org/info/rfc7231>.
[RFC7469] Evans, C., Palmer, C., and R. Sleevi, "Public Key Pinning
Extension for HTTP", RFC 7469, DOI 10.17487/RFC7469, April
2015, <https://www.rfc-editor.org/info/rfc7469>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016, RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>. <https://www.rfc-editor.org/info/rfc7950>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG", [RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016, RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>. <https://www.rfc-editor.org/info/rfc7951>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
skipping to change at page 84, line 38 skipping to change at page 87, line 33
and J. Nobre, "A Reference Model for Autonomic and J. Nobre, "A Reference Model for Autonomic
Networking", draft-ietf-anima-reference-model-10 (work in Networking", draft-ietf-anima-reference-model-10 (work in
progress), November 2018. progress), November 2018.
[I-D.ietf-anima-stable-connectivity] [I-D.ietf-anima-stable-connectivity]
Eckert, T. and M. Behringer, "Using Autonomic Control Eckert, T. and M. Behringer, "Using Autonomic Control
Plane for Stable Connectivity of Network OAM", draft-ietf- Plane for Stable Connectivity of Network OAM", draft-ietf-
anima-stable-connectivity-10 (work in progress), February anima-stable-connectivity-10 (work in progress), February
2018. 2018.
[I-D.ietf-netconf-keystore]
Watsen, K., "A YANG Data Model for a Keystore", draft-
ietf-netconf-keystore-12 (work in progress), July 2019.
[I-D.richardson-anima-state-for-joinrouter] [I-D.richardson-anima-state-for-joinrouter]
Richardson, M., "Considerations for stateful vs stateless Richardson, M., "Considerations for stateful vs stateless
join router in ANIMA bootstrap", draft-richardson-anima- join router in ANIMA bootstrap", draft-richardson-anima-
state-for-joinrouter-02 (work in progress), January 2018. state-for-joinrouter-02 (work in progress), January 2018.
[imprinting] [imprinting]
"Wikipedia article: Imprinting", July 2015, "Wikipedia article: Imprinting", July 2015,
<https://en.wikipedia.org/wiki/Imprinting_(psychology)>. <https://en.wikipedia.org/wiki/Imprinting_(psychology)>.
[IoTstrangeThings] [IoTstrangeThings]
skipping to change at page 107, line 26 skipping to change at page 110, line 26
Email: mcr+ietf@sandelman.ca Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/ URI: http://www.sandelman.ca/
Toerless Eckert Toerless Eckert
Futurewei Technologies Inc. USA Futurewei Technologies Inc. USA
2330 Central Expy 2330 Central Expy
Santa Clara 95050 Santa Clara 95050
USA USA
Email: ttef@cs.fau.de Email: tte+ietf@cs.fau.de
Michael H. Behringer Michael H. Behringer
Email: Michael.H.Behringer@gmail.com Email: Michael.H.Behringer@gmail.com
Kent Watsen Kent Watsen
Watsen Networks Watsen Networks
Email: kent+ietf@watsen.net Email: kent+ietf@watsen.net
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