[asterisk-security] AST-2018-004: Crash when receiving SUBSCRIBE request

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2018-004

          Product         Asterisk                                            
          Summary         Crash when receiving SUBSCRIBE request              
     Nature of Advisory   Remote Crash                                        
       Susceptibility     Remote Unauthenticated Sessions                     
          Severity        Major                                               
       Exploits Known     No                                                  
        Reported On       January 30, 2018                                    
        Reported By       Sandro Gauci                                        
         Posted On        February 21, 2018                                   
      Last Updated On     February 21, 2018                                   
      Advisory Contact    Joshua Colp <jcolp AT digium DOT com>               
          CVE Name       CVE-2018-7284                                        

    Description  When processing a SUBSCRIBE request the res_pjsip_pubsub     
                 module stores the accepted formats present in the Accept     
                 headers of the request. This code did not limit the number   
                 of headers it processed despite having a fixed limit of 32.  
                 If more than 32 Accept headers were present the code would   
                 write outside of its memory and cause a crash.               

    Resolution  The res_pjsip_pubsub module has been changed to enforce a     
                limit on the maximum number of Accept headers it will         
                process. To receive this change upgrade to the version of     
                Asterisk where this is resolved or apply the appropriate      
                provided patch.                                               

                               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               13.19.2, 14.7.6, 15.2.2         
            Certified Asterisk                      13.18-cert3               

                                     Patches                          
                                SVN URL                               Revision  
   http://downloads.asterisk.org/pub/security/AST-2018-004-13.diff    Asterisk  
                                                                      13        
   http://downloads.asterisk.org/pub/security/AST-2018-004-14.diff    Asterisk  
                                                                      14        
   http://downloads.asterisk.org/pub/security/AST-2018-004-15.diff    Asterisk  
                                                                      15        
   http://downloads.asterisk.org/pub/security/AST-2018-004-13.18.diff Certified 
                                                                      Asterisk  
                                                                      13.18     

       Links     https://issues.asterisk.org/jira/browse/ASTERISK-27640       

    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-2018-004.pdf and             
    http://downloads.digium.com/pub/security/AST-2018-004.html                

                                Revision History
          Date                 Editor                  Revisions Made         
    February 5, 2018   Joshua Colp              Initial Revision              
    February 21, 2018  Joshua Colp              Added CVE                     

               Asterisk Project Security Advisory - AST-2018-004
               Copyright © 2018 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.