[asterisk-security] AST-2013-002: Denial of Service in HTTP server

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2013-002

          Product         Asterisk                                            
          Summary         Denial of Service in HTTP server                    
     Nature of Advisory   Denial of Service                                   
       Susceptibility     Remote Unauthenticated Sessions                     
          Severity        Major                                               
       Exploits Known     None                                                
        Reported On       January 21, 2013                                    
        Reported By       Christoph Hebeisen, TELUS Security Labs             
         Posted On        March 27, 2013                                      
      Last Updated On     March 27, 2013                                      
      Advisory Contact    Mark Michelson <mmichelson AT digium DOT com>       
          CVE Name        CVE-2013-2686                                       

   Description AST-2012-014 [1], fixed in January of this year, contained a   
               fix for Asterisk's HTTP server since it was susceptible to a   
               remotely-triggered crash.                                      
                                                                              
               The fix put in place fixed the possibility for the crash to be 
               triggered, but a possible denial of service still exists if an 
               attacker sends one or more HTTP POST requests with very large  
               Content-Length values.                                         
                                                                              
               [1]                                                            
               http://downloads.asterisk.org/pub/security/AST-2012-014.html   

    Resolution  Content-Length is now capped at a maximum value of 1024       
                bytes. Any attempt to send an HTTP POST with content-length   
                greater than this cap will not result in any memory           
                allocated. The POST will be responded to with an HTTP 413     
                "Request Entity Too Large" response.                          

                               Affected Versions
           Product          Release Series    
    Asterisk Open Source         1.8.x        1.8.19.1, 1.8.20.0, 1.8.20.1    
    Asterisk Open Source         10.x         10.11.1, 10.12.0, 10.12.1       
    Asterisk Open Source         11.x         11.1.2, 11.2.0, 11.2.1          
     Certified Asterisk         1.8.15        1.8.15-cert1                    
    Asterisk Digiumphones  10.x-digiumphones  10.11.1-digiumphones,           
                                              10.12.0-digiumphones,           
                                              10.12.1-digiumphones            

                                  Corrected In
                 Product                              Release                 
          Asterisk Open Source               1.8.20.2, 10.12.2, 11.2.2        
           Certified Asterisk                      1.8.15-cert2               
          Asterisk Digiumphones                10.12.2-digiumphones           

                                     Patches                             
                                SVN URL                                  Revision  
http://downloads.asterisk.org/pub/security/AST-2012-014-1.8.diff         Asterisk  
                                                                         1.8       
http://downloads.asterisk.org/pub/security/AST-2012-014-10.diff          Asterisk  
                                                                         10        
http://downloads.asterisk.org/pub/security/AST-2012-014-11.diff          Asterisk  
                                                                         11        
http://downloads.asterisk.org/pub/security/AST-2012-014-1.8.15-cert.diff Certified 
                                                                         Asterisk  
                                                                         1.8.15    

   +------------------------------------------------------------------------+
   |  Links   | https://issues.asterisk.org/jira/browse/ASTERISK-20967      |
   |          | http://telussecuritylabs.com/threats/show/TSL20130327-01    |
   +------------------------------------------------------------------------+

    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-2013-002.pdf and             
    http://downloads.digium.com/pub/security/AST-2013-002.html                

                                Revision History
            Date                  Editor               Revisions Made         
    February 12, 2013      Mark Michelson        Initial Draft                
    March 27, 2013         Matt Jordan           Updated CVE                  

               Asterisk Project Security Advisory - AST-2013-002
              Copyright (c) 2013 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.