Addressing an Amplification Vulnerability in Session Initiation Protocol (SIP) Forking Proxies, December 2008
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- PROPOSED STANDARD
- RFC 3261
- R. Sparks, Ed.
- sip (rai)
This document normatively updates RFC 3261, the Session Initiation Protocol (SIP), to address a security vulnerability identified in SIP proxy behavior. This vulnerability enables an attack against SIP networks where a small number of legitimate, even authorized, SIP requests can stimulate massive amounts of proxy-to-proxy traffic. This document strengthens loop-detection requirements on SIP proxies when they fork requests (that is, forward a request to more than one destination). It also corrects and clarifies the description of the loop-detection algorithm such proxies are required to implement. Additionally, this document defines a Max-Breadth mechanism for limiting the number of concurrent branches pursued for any given request. [STANDARDS-TRACK]
For the definition of Status, see RFC 2026.
For the definition of Stream, see RFC 4844.