Since this document contains examples of SIP session establishment,
the security considerations in RFC 3261 [1] apply. RFC 3261
describes the basic threats including registration hijacking, server
impersonation, message body tampering, session modifying or teardown,
and denial of service and amplification attacks. The use of HTTP
Digest as shown in this document provides one-way authentication and
protection against replay attacks. TLS transport is used in
registration scenarios due to the lack of integrity protection in
HTTP Digest and the danger of registration hijacking without it, as
described in RFC 3261 [1]. A full discussion of the weaknesses of
HTTP Digest is provided in RFC 3261 [1]. The use of TLS and the
Secure SIP (sips) URI scheme provides a better level of security
including two-way authentication. S/MIME can provide end-to-end
confidentiality and integrity protection of message bodies, as
described in RFC 3261.
5. References
5.1. Normative References
[1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002.
[2] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with
SDP", RFC 3264, April 2002.
[3] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach,
P., Luotonen, A. and L. Stewart, "HTTP authentication: Basic and
Digest Access Authentication", RFC 2617, June 1999.
[4] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
5.2. Informative References
[5] Johnston, A., Donovan, S., Sparks, R., Cunningham, C. and K.
Summers, "Session Initiation Protocol (SIP) Public Switched
Telephone Network (PSTN) Call Flows", BCP 76, RFC 3666, December
2003.
6. Intellectual Property Statement
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intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
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7. Acknowledgments
This document is has been a group effort by the SIP and SIPPING WGs.
The authors wish to thank everyone who has read, reviewed, commented,
or made suggestions to improve this document.
Thanks to Rohan Mahy, Adam Roach, Gonzalo Camarillo, Cullen Jennings,
and Tom Taylor for their detailed comments during the final review.
Thanks to Dean Willis for his early contributions to the development
of this document.
The authors wish to thank Kundan Singh for performing parser
validation of messages.
The authors wish to thank the following individuals for their
participation in the review of this call flows document: Aseem
Agarwal, Rafi Assadi, Ben Campbell, Sunitha Kumar, Jon Peterson, Marc
Petit-Huguenin, Vidhi Rastogi, and Bodgey Yin Shaohua.
The authors also wish to thank the following individuals for their
assistance: Jean-Francois Mule, Hemant Agrawal, Henry Sinnreich,
David Devanatham, Joe Pizzimenti, Matt Cannon, John Hearty, the whole
MCI WorldCom IPOP Design team, Scott Orton, Greg Osterhout, Pat
Sollee, Doug Weisenberg, Danny Mistry, Steve McKinnon, and Denise
Ingram, Denise Caballero, Tom Redman, Ilya Slain, Pat Sollee, John
Truetken, and others from MCI WorldCom, 3Com, Cisco, Lucent and
Nortel.
8. Authors’ Addresses
All listed authors actively contributed large amounts of text to this
document.
Alan Johnston
MCI
100 South 4th Street
St. Louis, MO 63102
USA
EMail: alan.johnston@mci.com
Steve Donovan
dynamicsoft, Inc.
5100 Tennyson Parkway
Suite 1200
Plano, Texas 75024
USA
EMail: sdonovan@dynamicsoft.com
Robert Sparks
dynamicsoft, Inc.
5100 Tennyson Parkway
Suite 1200
Plano, Texas 75024
USA
EMail: rsparks@dynamicsoft.com
Chris Cunningham
dynamicsoft, Inc.
5100 Tennyson Parkway
Suite 1200
Plano, Texas 75024
USA
EMail: ccunningham@dynamicsoft.com
Kevin Summers
Sonus
1701 North Collins Blvd, Suite 3000
Richardson, TX 75080
USA
EMail: kevin.summers@sonusnet.com
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