AST-2012-002: Remote Crash Vulnerability in Milliwatt Application

           Asterisk Project Security Advisory - AST-2012-002

     Product        Asterisk                                              
     Summary        Remote Crash Vulnerability in Milliwatt Application   
Nature of Advisory  Exploitable Stack Buffer Overflow with locally        
                    defined data                                          
  Susceptibility    Remote Unauthenticated Sessions                       
     Severity       Minor                                                 
  Exploits Known    No                                                    
   Reported On      03/14/2012                                            
   Reported By      Russell Bryant                                        
    Posted On       03/15/2012                                            
 Last Updated On    March 15, 2012                                        
 Advisory Contact   Matt Jordan <mjordan AT digium DOT com>               
     CVE Name       

Description  An attacker can cause Asterisk to crash in one of two ways:  
                                                                          
             1. A dialplan uses the Milliwatt application with 'o'        
             option                                                       
                                                                          
             2. The internal_timing opion in asterisk.conf is off         
                                                                          
             3. The attacker sends a large audio packet. The number of    
             samples in the audio packet determines the number of         
             internal data samples that are copied into the buffer. This  
             overruns the buffer, potentially causing a crash.            
                                                                          
             OR                                                           
                                                                          
             1. A diaplan uses the Milliwatt application with the 'o'     
             option                                                       
                                                                          
             2. The attacker negotiates a media format with a sampling    
             rate greater than 32kHz. The application will attempt to     
             generate an audio packet using the sample rate of the        
             negotiated format, where the sample rate will require a      
             number of data points greater then the size of the buffer.   
             Again, the the application copies a number of internal data  
             samples into the buffer that are greater then the size of    
             the buffer, potentially causing a crash.                     
                                                                          
             Note that the latter attack vector is only possible in       
             Asterisk 10, as it supports codecs with a sample rate        
             greater then 32kHz.                                          

Resolution  Upgrade to one of the versions of Asterisk listed in the      
            "Corrected In" section, or apply a patch specified in the     
            "Patches" section.                                            

                           Affected Versions
            Product              Release Series  
     Asterisk Open Source            1.4.x       All Versions             
     Asterisk Open Source           1.6.2.x      All Versions             
     Asterisk Open Source            1.8.x       All Versions             
     Asterisk Open Source             10.x       All Versions             

                              Corrected In 
                 Product                              Release             
          Asterisk Open Source                        1.4.44              
          Asterisk Open Source                       1.6.2.23             
          Asterisk Open Source                       1.8.10.1             
          Asterisk Open Source                        10.2.1              

                                 Patches                          
                            SVN URL                               Revision 

http://downloads.asterisk.org/pub/security/AST-2012-002-1.4.diff v1.4
http://downloads.asterisk.org/pub/security/AST-2012-002-1.6.2.diff v1.6.2
http://downloads.asterisk.org/pub/security/AST-2012-002-1.8.diff v1.8
http://downloads.asterisk.org/pub/security/AST-2012-002-10.diff v10

   Links     https://issues.asterisk.org/jira/browse/ASTERISK-19541       

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/.pdf   
and http://downloads.digium.com/pub/security/.html                        

                            Revision History
      Date                  Editor                 Revisions Made         
03/15/2012         Matt Jordan               Initial Release              

           Asterisk Project Security Advisory - AST-2012-002
          Copyright (c) 2012 Digium, Inc. All Rights Reserved.

Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.