A new Request for Comments is now available in online RFC libraries. RFC 5393 Title: Addressing an Amplification Vulnerability in Session Initiation Protocol (SIP) Forking Proxies Author: R. Sparks, Ed., S. Lawrence, A. Hawrylyshen, B. Campen Status: Standards Track Date: December 2008 Mailbox: RjS@nostrum.com, scott.lawrence@nortel.com, alan.ietf@polyphase.ca, bcampen@estacado.net Pages: 20 Characters: 48722 Updates: RFC3261 I-D Tag: draft-ietf-sip-fork-loop-fix-08.txt URL: http://www.rfc-editor.org/rfc/rfc5393.txt 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] This document is a product of the Session Initiation Protocol Working Group of the IETF. This is now a Proposed Standard Protocol. STANDARDS TRACK: This document specifies an Internet standards track protocol for the Internet community,and requests discussion and suggestions for improvements. Please refer to the current edition of the Internet Official Protocol Standards (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. This announcement is sent to the IETF-Announce and rfc-dist lists. To subscribe or unsubscribe, see http://www.ietf.org/mailman/listinfo/ietf-announce http://mailman.rfc-editor.org/mailman/listinfo/rfc-dist For searching the RFC series, see http://www.rfc-editor.org/rfcsearch.html. For downloading RFCs, see http://www.rfc-editor.org/rfc.html. Requests for special distribution should be addressed to either the author of the RFC in question, or to rfc-editor@rfc-editor.org. Unless specifically noted otherwise on the RFC itself, all RFCs are for unlimited distribution. The RFC Editor Team USC/Information Sciences Institute _______________________________________________ IETF-Announce@ietf.org https://www.ietf.org/mailman/listinfo/ietf-announce