AST-2014-016: Remote Crash Vulnerability in PJSIP channel driver

   Asterisk Project Security Advisory - AST-2014-016

         Product        Asterisk
         Summary        Remote Crash Vulnerability in PJSIP channel driver
    Nature of Advisory  Denial of Service
      Susceptibility    Remote Unauthenticated Sessions
         Severity       Critical
      Exploits Known    No
       Reported On      17 November 2014
       Reported By      Joshua Colp
        Posted On       20 November 2014
     Last Updated On    November 20, 2014
     Advisory Contact   Joshua Colp <jcolp AT digium DOT com>
         CVE Name       Pending

    Description  When handling an INVITE with Replaces message the
                 res_pjsip_refer module incorrectly assumes that it will be
                 operating on a channel that has just been created. If the
                 INVITE with Replaces message is sent in-dialog after a
                 session has been established this assumption will be
                 incorrect. The res_pjsip_refer module will then hang up a
                 channel that is actually owned by another thread. When this
                 other thread attempts to use the just hung up channel it
                 will end up using freed channel which will likely cause a
                 crash.

    Resolution  If REFER support is not required the res_pjsip_refer module
                can be unloaded to limit exposure otherwise the
                res_pjsip_refer module has been patched so it will not allow
                an in-dialog INVITE with Replaces message to be processed.

                               Affected Versions
                         Product                       Release
                                                       Series
                  Asterisk Open Source                  12.x    All versions
                  Asterisk Open Source                  13.x    All versions

                                  Corrected In
                            Product                              Release
                      Asterisk Open Source                    12.7.1, 13.0.1

                                    Patches
                                SVN URL                              Revision
   http://downloads.asterisk.org/pub/security/AST-2014-016-12.diff   Asterisk
                                                                     12
   http://downloads.asterisk.org/pub/security/AST-2014-016-13.diff   Asterisk
                                                                     13

    Links  https://issues.asterisk.org/jira/browse/ASTERISK-24471

    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-2014-016.pdf and
    http://downloads.digium.com/pub/security/AST-2014-016.html

                                Revision History
                      Date                       Editor      Revisions Made
    November 20 2014                           Joshua Colp  Initial Revision

               Asterisk Project Security Advisory - AST-2014-016
              Copyright (c) 2014 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.