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AST-2012-008: Skinny Channel Driver Remote Crash Vulnerability

From: Asterisk Security Team (securityasterisk.org)
Date: Tue May 29 2012 - 16:55:52 CDT

               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, 10.4.1
             Certified Asterisk 1.8.11-cert2

                                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
    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

                                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.