AST-2011-014: Remote crash possibility with SIP and the “automon” feature enabled

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2011-014

         Product        Asterisk                                              
         Summary        Remote crash possibility with SIP and the "automon"   
                        feature enabled                                       
    Nature of Advisory  Remote crash vulnerability in a feature that is       
                        disabled by default                                   
      Susceptibility    Remote unauthenticated sessions                       
         Severity       Moderate                                              
      Exploits Known    Yes                                                   
       Reported On      November 2, 2011                                      
       Reported By      Kristijan Vrban                                       
        Posted On       2011-11-03                                            
     Last Updated On    December 7, 2011                                      
     Advisory Contact   Terry Wilson <twilson at digium.com>                     
         CVE Name       

    Description  When the "automon" feature is enabled in features.conf, it   
                 is possible to send a sequence of SIP requests that cause    
                 Asterisk to dereference a NULL pointer and crash.            

    Resolution  Applying the referenced patches that check that the pointer   
                is not NULL before accessing it will resolve the issue. The   
                "automon" feature can be disabled in features.conf as a       
                workaround.                                                   

                               Affected Versions
                Product              Release Series  
         Asterisk Open Source           1.6.2.x      All versions             
         Asterisk Open Source            1.8.x       All versions             

                                  Corrected In
                   Product                              Release               
            Asterisk Open Source                   1.6.2.21, 1.8.7.2          

                                     Patches                          
                              Download URL                            Revision 
   http://downloads.asterisk.org/pub/security/AST-2011-014-1.6.2.diff 1.6.2.20 
   http://downloads.asterisk.org/pub/security/AST-2011-014-1.8.diff   1.8.7.1  

            Links          

    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-2011-014.pdf and             
    http://downloads.digium.com/pub/security/AST-2011-014.html                

                                Revision History
           Date                 Editor                 Revisions Made         

               Asterisk Project Security Advisory - AST-2011-014
              Copyright (c) 2011 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.