Asterisk Project Security Advisory - AST-2013-002 Product Asterisk Summary Denial of Service in HTTP server Nature of Advisory Denial of Service Susceptibility Remote Unauthenticated Sessions Severity Major Exploits Known None Reported On January 21, 2013 Reported By Christoph Hebeisen, TELUS Security Labs Posted On March 27, 2013 Last Updated On March 27, 2013 Advisory Contact Mark Michelson CVE Name CVE-2013-2686 Description AST-2012-014 [1], fixed in January of this year, contained a fix for Asterisk's HTTP server since it was susceptible to a remotely-triggered crash. The fix put in place fixed the possibility for the crash to be triggered, but a possible denial of service still exists if an attacker sends one or more HTTP POST requests with very large Content-Length values. [1] http://downloads.asterisk.org/pub/security/AST-2012-014.html Resolution Content-Length is now capped at a maximum value of 1024 bytes. Any attempt to send an HTTP POST with content-length greater than this cap will not result in any memory allocated. The POST will be responded to with an HTTP 413 "Request Entity Too Large" response. Affected Versions Product Release Series Asterisk Open Source 1.8.x 1.8.19.1, 1.8.20.0, 1.8.20.1 Asterisk Open Source 10.x 10.11.1, 10.12.0, 10.12.1 Asterisk Open Source 11.x 11.1.2, 11.2.0, 11.2.1 Certified Asterisk 1.8.15 1.8.15-cert1 Asterisk Digiumphones 10.x-digiumphones 10.11.1-digiumphones, 10.12.0-digiumphones, 10.12.1-digiumphones Corrected In Product Release Asterisk Open Source 1.8.20.2, 10.12.2, 11.2.2 Certified Asterisk 1.8.15-cert2 Asterisk Digiumphones 10.12.2-digiumphones Patches SVN URL Revision http://downloads.asterisk.org/pub/security/AST-2012-014-1.8.diff Asterisk 1.8 http://downloads.asterisk.org/pub/security/AST-2012-014-10.diff Asterisk 10 http://downloads.asterisk.org/pub/security/AST-2012-014-11.diff Asterisk 11 http://downloads.asterisk.org/pub/security/AST-2012-014-1.8.15-cert.diff Certified Asterisk 1.8.15 +------------------------------------------------------------------------+ | Links | https://issues.asterisk.org/jira/browse/ASTERISK-20967 | | | http://telussecuritylabs.com/threats/show/TSL20130327-01 | +------------------------------------------------------------------------+ Asterisk Project Security Advisories are posted at http://www.asterisk.org/security This document may be superseded by later versions; if so, the latest version will be posted at http://downloads.digium.com/pub/security/AST-2013-002.pdf and http://downloads.digium.com/pub/security/AST-2013-002.html Revision History Date Editor Revisions Made February 12, 2013 Mark Michelson Initial Draft March 27, 2013 Matt Jordan Updated CVE Asterisk Project Security Advisory - AST-2013-002 Copyright (c) 2013 Digium, Inc. All Rights Reserved. Permission is hereby granted to distribute and publish this advisory in its original, unaltered form.