draft-ietf-sipcore-digest-scheme-14.txt   draft-ietf-sipcore-digest-scheme-15.txt 
SIP Core R. Shekh-Yusef SIP Core R. Shekh-Yusef
Internet-Draft Avaya Internet-Draft Avaya
Updates: 3261 (if approved) October 30, 2019 Updates: 3261 (if approved) November 3, 2019
Intended status: Standards Track Intended status: Standards Track
Expires: May 2, 2020 Expires: May 6, 2020
The Session Initiation Protocol (SIP) Digest Authentication Scheme The Session Initiation Protocol (SIP) Digest Authentication Scheme
draft-ietf-sipcore-digest-scheme-14 draft-ietf-sipcore-digest-scheme-15
Abstract Abstract
This document updates RFC 3261 by updating the Digest Access This document updates RFC 3261 by updating the Digest Access
Authentication scheme used by the Session Initiation Protocol (SIP) Authentication scheme used by the Session Initiation Protocol (SIP)
to add support for more secure digest algorithms, e.g., SHA-256 and to add support for more secure digest algorithms, e.g., SHA-256 and
SHA-512-256, to replace the broken MD5 algorithm. SHA-512-256, to replace the obsolete MD5 algorithm.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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 May 2, 2020. This Internet-Draft will expire on May 6, 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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allowed, since it provides integrity checks over the bodies and allowed, since it provides integrity checks over the bodies and
provides mutual authentication. provides mutual authentication.
2.7. Augmented BNF for SIP 2.7. Augmented BNF for SIP
This document updates the Augmented BNF [RFC5234] for SIP as follows. This document updates the Augmented BNF [RFC5234] for SIP as follows.
It extends the request-digest as follows to allow for different It extends the request-digest as follows to allow for different
digest sizes: digest sizes:
request-digest = LDQUOT 32*LHEX RDQUOT request-digest = LDQUOT *LHEX RDQUOT
The number of hex digits is implied by the length of the value of the The number of hex digits is implied by the length of the value of the
algorithm used. algorithm used, with the minimum size of 32. A parameter with an
empty value (empty string) is allowed when the UAC has not yet
received a challenge.
It extends the algorithm parameter as follows to allow for any It extends the algorithm parameter as follows to allow for any
algorithm in the registry to be used: algorithm in the registry to be used:
algorithm = "algorithm" EQUAL ( "MD5" / "MD5-sess" / "SHA-256" / algorithm = "algorithm" EQUAL ( "MD5" / "MD5-sess" / "SHA-256" /
"SHA-256-sess" / "SHA-512-256" / "SHA-512-256-sess" / token ) "SHA-256-sess" / "SHA-512-256" / "SHA-512-256-sess" / token )
3. Security Considerations 3. Security Considerations
This specification adds new secure algorithms to be used with the This specification adds new secure algorithms to be used with the
Digest mechanism to authenticate users. The broken MD5 algorithm Digest mechanism to authenticate users. The obsolete MD5 algorithm
remains only for backward compatibility with [RFC2617] but its use is remains only for backward compatibility with [RFC2617] but its use is
NOT RECOMMENDED. NOT RECOMMENDED.
This opens the system to the potential of a downgrade attack by an This opens the system to the potential of a downgrade attack by an
on-path attacker. The most effective way of dealing with this type on-path attacker. The most effective way of dealing with this type
of attack is to either validate the client and challenge it of attack is to either validate the client and challenge it
accordingly, or remove the support for backward compatibility by not accordingly, or remove the support for backward compatibility by not
supporting MD5. supporting MD5.
See section 5 of [RFC7616] for a detailed security discussion of the See section 5 of [RFC7616] for a detailed security discussion of the
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This document has no actions for IANA. This document has no actions for IANA.
5. Acknowledgments 5. Acknowledgments
The author would like to thank the following individuals for their The author would like to thank the following individuals for their
careful reviews, comments, and suggestions: Paul Kyzivat, Olle careful reviews, comments, and suggestions: Paul Kyzivat, Olle
Johansson, Dale Worley, Michael Procter, Inaki Baz Castillo, Tolga Johansson, Dale Worley, Michael Procter, Inaki Baz Castillo, Tolga
Asveren, Christer Holmberg, Brian Rosen, Jean Mahoney, Adam Roach, Asveren, Christer Holmberg, Brian Rosen, Jean Mahoney, Adam Roach,
Barry Leiba, Roni Even, Eric Vyncke, Benjamin Kaduk, Alissa Cooper, Barry Leiba, Roni Even, Eric Vyncke, Benjamin Kaduk, Alissa Cooper,
Roman Danyliw, and Alexey Melnikov. . Roman Danyliw, and Alexey Melnikov, and Maxim Sobolev. .
6. References 6. References
6.1. Normative References 6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
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