AST-2017-012: Remote Crash Vulnerability in RTCP Stack

Asterisk Project Security Advisory - AST-2017-012 Product Asterisk Summary Remote Crash Vulnerability in RTCP Stack Nature of Advisory Denial of Service Susceptibility Remote Unauthenticated Sessions Severity Moderate Exploits Known No Reported On October 30, 2017 Reported By Tzafrir Cohen and Vitezslav Novy Posted On December 13, 2017 Last Updated On December 12, 2017 Advisory Contact Jcolp AT digium DOT com CVE Name Description If a compound RTCP packet is received containing more than one report (for example a Receiver Report and a Sender Report) the RTCP stack will incorrectly store report information outside of allocated memory potentially causing a crash. For all versions of Asterisk this vulnerability requires an active call to be established. For versions of Asterisk 13.17.2, 14.6.2, 15.0.0, 13.13-cert6 and greater an additional level of security is placed upon RTCP packets. If the probation period for incoming RTP traffic has passed any received RTCP packets must contain the same SSRC as the RTP traffic. If the RTCP packets do not then they are dropped. This ensures other parties can not inject RTCP packets without they themselves establishing an active call. Resolution The RTCP stack has been changed so the report information is always stored in allocated memory. The provided patches can be applied to the appropriate version or the latest version of Asterisk can be installed to receive the fix. Affected Versions Product Release Series Asterisk Open Source 13.x All Versions Asterisk Open Source 14.x All Versions Asterisk Open Source 15.x All Versions Certified Asterisk 13.13 All Versions Corrected In Product Release Asterisk Open Source 13.18.4, 14.7.4, 15.1.4 Certified Asterisk 13.13-cert9 Patches SVN URL Revision http://downloads.asterisk.org/pub/security/AST-2017-012-13.diff Asterisk 13 http://downloads.asterisk.org/pub/security/AST-2017-012-14.diff Asterisk 14 http://downloads.asterisk.org/pub/security/AST-2017-012-15.diff Asterisk 15 http://downloads.asterisk.org/pub/security/AST-2017-012-13.13.diff Certified Asterisk 13.13 Links https://issues.asterisk.org/jira/browse/ASTERISK-27382 https://issues.asterisk.org/jira/browse/ASTERISK-27429 Asterisk Project Security Advisories are posted at http://www.asterisk.org/security This document may be superseded by later versions; if so, the latest version will be posted at http://downloads.digium.com/pub/security/AST-2017-012.pdf and http://downloads.digium.com/pub/security/AST-2017-012.html Revision History Date Editor Revisions Made November 30, 2017 Joshua Colp Initial Revision Asterisk Project Security Advisory - AST-2017-012 Copyright © 2017 Digium, Inc. All Rights Reserved. Permission is hereby granted to distribute and publish this advisory in its original, unaltered form.