[asterisk-security] AST-2014-008: Denial of Service in PJSIP Channel Driver Subscriptions

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2014-008

         Product        Asterisk                                              
         Summary        Denial of Service in PJSIP Channel Driver             
                        Subscriptions                                         
    Nature of Advisory  Denial of Service                                     
      Susceptibility    Remote authenticated sessions                         
         Severity       Moderate                                              
      Exploits Known    No                                                    
       Reported On      28 May, 2014                                          
       Reported By      Mark Michelson                                        
        Posted On       June 12, 2014                                         
     Last Updated On    June 12, 2014                                         
     Advisory Contact   Mark Michelson <mmichelson AT digium DOT com>         
         CVE Name       CVE-2014-4048                                         

    Description  When a SIP transaction timeout caused a subscription to be   
                 terminated, the action taken by Asterisk was guaranteed to   
                 deadlock the thread on which SIP requests are serviced.      
                                                                              
                 Note that this behavior could only happen on established     
                 subscriptions, meaning that this could only be exploited if  
                 an attacker bypassed authentication and successfully         
                 subscribed to a real resource on the Asterisk server.        

    Resolution  The socket-servicing thread is now no longer capable of       
                dispatching synchronous tasks to other threads since that     
                may result in deadlocks.                                      

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

                                  Corrected In  
                     Product                              Release             
               Asterisk Open Source                        12.3.1             

                                    Patches                        
                               SVN URL                              Revision  
   http://downloads.asterisk.org/pub/security/AST-2014-008-12.diff Asterisk   
                                                                   12         

       Links     https://issues.asterisk.org/jira/browse/ASTERISK-23802       

    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-2014-008.pdf and             
    http://downloads.digium.com/pub/security/AST-2014-008.html                

                                Revision History
          Date                  Editor                 Revisions Made         
    June 6, 2014       Mark Michelson            Document Creation            
    June 12, 2014      Matt Jordan               Added CVE                    

               Asterisk Project Security Advisory - AST-2014-008
              Copyright (c) 2014 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.