Asterisk Project Security Advisory - AST-2017-014

         Product        Asterisk                                              
         Summary        Crash in PJSIP resource when missing a contact        
                        header                                                
    Nature of Advisory  Remote Crash                                          
      Susceptibility    Remote Unauthenticated Sessions                       
         Severity       Moderate                                              
      Exploits Known    No                                                    
       Reported On      December 12, 2017                                     
       Reported By      Ross Beer                                             
        Posted On       
     Last Updated On    December 22, 2017                                     
     Advisory Contact   Kevin Harwell <kharwell AT digium DOT com>            
         CVE Name       

    Description  A select set of SIP messages create a dialog in Asterisk.    
                 Those SIP messages must contain a contact header. For those  
                 messages, if the header was not present and using the PJSIP  
                 channel driver, it would cause Asterisk to crash. The        
                 severity of this vulnerability is somewhat mitigated if      
                 authentication is enabled. If authentication is enabled a    
                 user would have to first be authorized before reaching the   
                 crash point.                                                 

    Resolution  When using the Asterisk PJSIP resource, and one of the SIP    
                messages that create a dialog is received Asterisk now        
                checks to see if the message contains a contact header. If    
                it does not Asterisk now responds with a "400 Missing         
                Contact header".                                              

                               Affected Versions       
                         Product                       Release  
                                                       Series   
                  Asterisk Open Source                  13.x    All versions  
                  Asterisk Open Source                  14.x    All versions  
                  Asterisk Open Source                  15.x    All versions  
                   Certified Asterisk                   13.18   All versions  

                                  Corrected In
          Product                              Release                        
    Asterisk Open Source               13.18.5, 14.7.5, 15.1.5                
     Certified Asterisk                      13.18-cert2                      

                                     Patches                          
                                SVN URL                               Revision  
   http://downloads.asterisk.org/pub/security/AST-2017-014-13.diff    Asterisk  
                                                                      13        
   http://downloads.asterisk.org/pub/security/AST-2017-014-14.diff    Asterisk  
                                                                      14        
   http://downloads.asterisk.org/pub/security/AST-2017-014-15.diff    Asterisk  
                                                                      15        
   http://downloads.asterisk.org/pub/security/AST-2017-014-13.18.diff Certified 
                                                                      Asterisk  
                                                                      13.18     

    Links  https://issues.asterisk.org/jira/browse/ASTERISK-27480             

    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-2017-014.pdf and             
    http://downloads.digium.com/pub/security/AST-2017-014.html                

                                Revision History
                     Date                       Editor       Revisions Made   
    December 20, 2017                        Kevin Harwell  Initial Revision  

               Asterisk Project Security Advisory - AST-2017-014
              Copyright (c) 2017 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.