[asterisk-security] AST-2014-014: High call load may result in hung channels in ConfBridge.

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2014-014

         Product        Asterisk                                              
         Summary        High call load may result in hung channels in         
                        ConfBridge.                                           
    Nature of Advisory  Denial of Service                                     
      Susceptibility    Remote Unauthenticated Sessions                       
         Severity       Moderate                                              
      Exploits Known    No                                                    
       Reported On      19 October, 2014                                      
       Reported By      Ben Klang                                             
        Posted On       20 November 2014                                      
     Last Updated On    November 20, 2014                                     
     Advisory Contact   Joshua Colp <jcolp AT digium DOT com>                 
         CVE Name       Pending                                               

    Description  The ConfBridge application uses an internal bridging API to  
                 implement conference bridges. This internal API uses a       
                 state model for channels within the conference bridge and    
                 transitions between states as different things occur. Under  
                 load it is possible for some state transitions to be         
                 delayed causing the channel to transition from being hung    
                 up to waiting for media. As the channel has been hung up     
                 remotely no further media will arrive and the channel will   
                 stay within ConfBridge indefinitely.                         

    Resolution  The underlying bridging code that ConfBridge uses has been    
                fixed so state changes can not occur that will take a         
                channel out of the hung up state.                             

                               Affected Versions       
                         Product                       Release  
                                                       Series   
                  Asterisk Open Source                  11.x    All versions  
                   Certified Asterisk                   11.6    All versions  

                                  Corrected In                    
                              Product                              Release    
                        Asterisk Open Source                       11.14.1    
                         Certified Asterisk                       11.6-cert8  

                                     Patches                         
                                SVN URL                              Revision  
    http://downloads.asterisk.org/pub/security/AST-2014-014-11.diff  Asterisk  
                                                                        11     
   http://downloads.asterisk.org/pub/security/AST-2014-014-11.6.diff Certified 
                                                                     Asterisk  
                                                                       11.6    

    Links  https://issues.asterisk.org/jira/browse/ASTERISK-24440             

    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-2014-014.pdf and             
    http://downloads.digium.com/pub/security/AST-2014-014.html                

                                Revision History
          Date           Editor                  Revisions Made               
    20 November, 2014  Joshua Colp  Initial Advisory created                  

               Asterisk Project Security Advisory - AST-2014-014
              Copyright (c) 2014 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.