[asterisk-security] AST-2017-002: Buffer Overrun in PJSIP transaction layer

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2017-002

         Product        Asterisk                                              
         Summary        Buffer Overrun in PJSIP transaction layer             
    Nature of Advisory  Buffer Overrun/Crash                                  
      Susceptibility    Remote Unauthenticated Sessions                       
         Severity       Critical                                              
      Exploits Known    No                                                    
       Reported On      12 April, 2017                                        
       Reported By      Sandro Gauci                                          
        Posted On       
     Last Updated On    April 13, 2017                                        
     Advisory Contact   Mark Michelson <mark DOT michelson AT digium DOT      
                        com>                                                  
         CVE Name       

    Description  A remote crash can be triggered by sending a SIP packet to   
                 Asterisk with a specially crafted CSeq header and a Via      
                 header with no branch parameter. The issue is that the       
                 PJSIP RFC 2543 transaction key generation algorithm does     
                 not allocate a large enough buffer. By overrunning the       
                 buffer, the memory allocation table becomes corrupted,       
                 leading to an eventual crash.                                
                                                                              
                 This issue is in PJSIP, and so the issue can be fixed        
                 without performing an upgrade of Asterisk at all. However,   
                 we are releasing a new version of Asterisk with the bundled  
                 PJProject updated to include the fix.                        
                                                                              
                 If you are running Asterisk with chan_sip, this issue does   
                 not affect you.                                              

    Resolution  A patch created by the Asterisk team has been submitted and   
                accepted by the PJProject maintainers.                        

                               Affected Versions       
                         Product                       Release  
                                                       Series   
                  Asterisk Open Source                  11.x    Unaffected    
                  Asterisk Open Source                  13.x    All versions  
                  Asterisk Open Source                  14.x    All versions  
                   Certified Asterisk                   13.13   All versions  

                                  Corrected In               
                            Product                              Release      
                     Asterisk Open Source                    13.15.1, 14.4.1  
                      Certified Asterisk                       13.13-cert4    

                                    Patches
                 SVN URL                              Revision                

    Links  https://issues.asterisk.org/jira/browse/ASTERISK-26938             

    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-2017-002.pdf and             
    http://downloads.digium.com/pub/security/AST-2017-002.html                

                                Revision History
         Date           Editor                   Revisions Made               
    12 April, 2017  Mark Michelson  Initial report created                    

               Asterisk Project Security Advisory - AST-2017-002
              Copyright (c) 2017 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.