[asterisk-dev] AST-2021-003: Remote attacker could prematurely tear down SRTP calls

[Asterisk Security Team]

               Asterisk Project Security Advisory - AST-2021-003

         Product        Asterisk                                              
         Summary        Remote attacker could prematurely tear down SRTP      
                        calls                                                 
    Nature of Advisory  Denial of Service                                     
      Susceptibility    Remote unauthenticated sessions                       
         Severity       Moderate                                              
      Exploits Known    No                                                    
       Reported On      January 22, 2021                                      
       Reported By      Alexander Traud                                       
        Posted On       
     Last Updated On    February 11, 2021                                     
     Advisory Contact   gjoseph AT sangoma DOT com                            
         CVE Name       CVE-2021-26712                                        

      Description     An unauthenticated remote attacker could replay SRTP    
                      packets which could cause an Asterisk instance          
                      configured without strict RTP validation to tear down   
                      calls prematurely.                                      
    Modules Affected  res_srtp.c res_rtp_asterisk.c                           

    Resolution  Asterisk now implements SRTP replay protection via a          
                “srtpreplayprotection” option in rtp.conf. The default is     
                “yes”                                                         

                               Affected Versions
                Product               Release Series  
          Asterisk Open Source             13.x       13.38.1                 
          Asterisk Open Source             16.x       16.16.0                 
          Asterisk Open Source             17.x       17.9.1                  
          Asterisk Open Source             18.x       18.2.0                  
           Certified Asterisk              16.x       16.8-cert5              

                                  Corrected In
               Product                              Release                   
        Asterisk Open Source           13.38.2, 16.16.1, 17.9.2, 18.2.1       
         Certified Asterisk                       16.8-cert6                  

                                     Patches                         
                               Patch URL                              Revision  
   https:/downloads.asterisk.org/pub/security/AST-2021-003-13.diff   13.38.2    
   https:/downloads.asterisk.org/pub/security/AST-2021-003-16.diff   16.16.1    
   https:/downloads.asterisk.org/pub/security/AST-2021-003-17.diff   17.9.2     
   https:/downloads.asterisk.org/pub/security/AST-2021-003-18.diff   18.2.1     
   https:/downloads.asterisk.org/pub/security/AST-2021-003-16.8.diff Certified  
                                                                     Asterisk   
                                                                     16.8-cert6 

     Links   https://issues.asterisk.org/jira/browse/ASTERISK-29260           
                                                                              
             https://downloads.asterisk.org/pub/security/AST-2021-003.html    

    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                                                 
    https://downloads.digium.com/pub/security/AST-2021-003.pdf and            
    https://downloads.digium.com/pub/security/AST-2021-003.html               

                                Revision History
          Date                  Editor                 Revisions Made         
    February 4, 2021   George Joseph             Initial                      
    February 5, 2021   George Joseph             Added CVE ID                 

               Asterisk Project Security Advisory - AST-2021-003
               Copyright © 2021 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.