Asterisk Project Security Advisory - AST-2012-008 Product Asterisk Summary Skinny Channel Driver Remote Crash Vulnerability Nature of Advisory Denial of Service Susceptibility Remote authenticated sessions Severity Minor Exploits Known No Reported On May 22, 2012 Reported By Christoph Hebeisen Posted On May 29, 2012 Last Updated On May 29, 2012 Advisory Contact Matt Jordan < mjordan AT digium DOT com > CVE Name CVE-2012-2948 Description As reported by Telus Labs: "A Null-pointer dereference has been identified in the SCCP (Skinny) channel driver of Asterisk. When an SCCP client closes its connection to the server, a pointer in a structure is set to Null. If the client was not in the on-hook state at the time the connection was closed, this pointer is later dereferenced. A remote attacker with a valid SCCP ID can can use this vulnerability by closing a connection to the Asterisk server in certain call states (e.g. "Off hook") to crash the server. Successful exploitation of this vulnerability would result in termination of the server, causing denial of service to legitimate users." Resolution The pointer to the device in the structure is now checked before it is dereferenced in the channel event callbacks and message handling functions. Affected Versions Product Release Series Asterisk Open Source 1.8.x All Versions Asterisk Open Source 10.x All Versions Certified Asterisk 1.8.11-cert 1.8.11-cert1 Corrected In Product Release Asterisk Open Source 1.8.12.1, 10.4.1 Certified Asterisk 1.8.11-cert2 Patches SVN URL Revision http://downloads.asterisk.org/pub/security/AST-2012-008-1.8.diff v1.8 http://downloads.asterisk.org/pub/security/AST-2012-008-10.diff v10 http://downloads.asterisk.org/pub/security/AST-2012-008-1.8.11-cert.diff v1.8.11-cert Links https://issues.asterisk.org/jira/browse/ASTERISK-19905 Asterisk Project Security Advisories are posted at http://www.asterisk.org/security This document may be superseded by later versions; if so, the latest version will be posted at http://downloads.digium.com/pub/security/AST-2012-008.pdf and http://downloads.digium.com/pub/security/AST-2012-008.html Revision History Date Editor Revisions Made 05/25/2012 Matt Jordan Initial Release Asterisk Project Security Advisory - AST-2012-008 Copyright (c) 2012 Digium, Inc. All Rights Reserved. Permission is hereby granted to distribute and publish this advisory in its original, unaltered form.
Stabilization happening in bug 418189.
CVE-2012-2948 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2012-2948): chan_skinny.c in the Skinny (aka SCCP) channel driver in Certified Asterisk 1.8.11-cert before 1.8.11-cert2 and Asterisk Open Source 1.8.x before 1.8.12.1 and 10.x before 10.4.1 allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) by closing a connection in off-hook mode.
This issue was resolved and addressed in GLSA 201206-05 at http://security.gentoo.org/glsa/glsa-201206-05.xml by GLSA coordinator Sean Amoss (ackle).
