[asterisk-security] AST-2011-002: Multiple array overflow and crash vulnerabilities in UDPTL code

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2011-002

        Product       Asterisk                                                
        Summary       Multiple array overflow and crash vulnerabilities in    
                      UDPTL code                                              
   Nature of Advisory Exploitable Stack and Heap Array Overflows              
     Susceptibility   Remote Unauthenticated Sessions                         
        Severity      Critical                                                
     Exploits Known   No                                                      
      Reported On     January 27, 2011                                        
      Reported By     Matthew Nicholson                                       
       Posted On      February 21, 2011                                       
    Last Updated On   February 21, 2011                                       
    Advisory Contact  Matthew Nicholson <mnicholson at digium.com>               
        CVE Name      

   Description When decoding UDPTL packets, multiple stack and heap based     
               arrays can be made to overflow by specially crafted packets.   
               Systems doing T.38 pass through or termination are vulnerable. 

   Resolution The UDPTL decoding routines have been modified to respect the   
              limits of exploitable arrays.                                   
                                                                              
              In asterisk versions not containing the fix for this issue,     
              disabling T.38 support will prevent this vulnerability from     
              being exploited. T.38 support can be disabled in chan_sip by    
              setting the t38pt_udptl option to "no" (it is off by default).  
                                                                              
              t38pt_udptl = no                                                
                                                                              
              The chan_ooh323 module should also be disabled by adding the    
              following line in modles.conf.                                  
                                                                              
              noload => chan_ooh323                                           

                               Affected Versions
                Product              Release Series 
         Asterisk Open Source            1.4.x      All versions              
         Asterisk Open Source            1.6.x      All versions              
       Asterisk Business Edition         C.x.x      All versions              
              AsteriskNOW                 1.5       All versions              
      s800i (Asterisk Appliance)         1.2.x      All versions              

                                  Corrected In
              Product                               Release                   
        Asterisk Open Source        1.4.39.2, 1.6.1.22, 1.6.2.16.2, 1.8.2.4   
     Asterisk Business Edition                      C.3.6.3                   

                                    Patches                            
                                   URL                                 Branch 
   http://downloads.asterisk.org/pub/security/AST-2011-002-1.4.diff    1.4    
   http://downloads.asterisk.org/pub/security/AST-2011-002-1.6.1.diff  1.6.1  
   http://downloads.asterisk.org/pub/security/AST-2011-002-1.6.2.diff  1.6.2  
   http://downloads.asterisk.org/pub/security/AST-2011-002-1.8.diff    1.8    

          Links         

   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-2011-002.pdf and              
   http://downloads.digium.com/pub/security/AST-2011-002.html                 

                                Revision History
        Date                Editor                    Revisions Made          
   02/21/11        Matthew Nicholson         Initial Release                  

               Asterisk Project Security Advisory - AST-2011-002
              Copyright (c) 2011 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.