[asterisk-security] AST-2016-002: File descriptor exhaustion in chan_sip

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2016-002

         Product        Asterisk                                              
         Summary        File descriptor exhaustion in chan_sip                
    Nature of Advisory  Denial of Service                                     
      Susceptibility    Remote Unauthenticated Sessions                       
         Severity       Minor                                                 
      Exploits Known    Yes                                                   
       Reported On      September 17, 2015                                    
       Reported By      Alexander Traud                                       
        Posted On       February 3, 2016                                      
     Last Updated On    February 3, 2016                                      
     Advisory Contact   Richard Mudgett <rmudgett AT digium DOT com>          
         CVE Name       Pending                                               

    Description  Setting the sip.conf timert1 value to a value higher than    
                 1245 can cause an integer overflow and result in large       
                 retransmit timeout times. These large timeout values hold    
                 system file descriptors hostage and can cause the system to  
                 run out of file descriptors.                                 

    Resolution  Setting the sip.conf timert1 value to 1245 or lower will not  
                exhibit the vulnerability. The default timert1 value is 500.  
                Asterisk has been patched to detect the integer overflow and  
                calculate the previous retransmission timer value.            

                               Affected Versions       
                         Product                       Release  
                                                       Series   
                  Asterisk Open Source                  1.8.x   All versions  
                  Asterisk Open Source                  11.x    All versions  
                  Asterisk Open Source                  12.x    All versions  
                  Asterisk Open Source                  13.x    All versions  
                   Certified Asterisk                  1.8.28   All versions  
                   Certified Asterisk                   11.6    All versions  
                   Certified Asterisk                   13.1    All versions  

                                  Corrected In
          Product                              Release                        
    Asterisk Open Source                   11.21.1, 13.7.1                    
     Certified Asterisk                11.6-cert12, 13.1-cert3                

                                      Patches                          
                                 SVN URL                               Revision  
   http://downloads.asterisk.org/pub/security/AST-2016-002-1.8.28.diff Certified 
                                                                       Asterisk  
                                                                       1.8.28    
   http://downloads.asterisk.org/pub/security/AST-2016-002-11.6.diff   Certified 
                                                                       Asterisk  
                                                                       11.6      
   http://downloads.asterisk.org/pub/security/AST-2016-002-13.1.diff   Certified 
                                                                       Asterisk  
                                                                       13.1      
   http://downloads.asterisk.org/pub/security/AST-2016-002-1.8.diff    Asterisk  
                                                                       1.8       
   http://downloads.asterisk.org/pub/security/AST-2016-002-11.diff     Asterisk  
                                                                       11        
   http://downloads.asterisk.org/pub/security/AST-2016-002-12.diff     Asterisk  
                                                                       12        
   http://downloads.asterisk.org/pub/security/AST-2016-002-13.diff     Asterisk  
                                                                       13        

    Links  https://issues.asterisk.org/jira/browse/ASTERISK-25397             

    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-2016-002.pdf and             
    http://downloads.digium.com/pub/security/AST-2016-002.html                

                                Revision History
           Date             Editor                 Revisions Made             
    September 29, 2015  Richard Mudgett  Initial document created             

               Asterisk Project Security Advisory - AST-2016-002
              Copyright (c) 2015 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.