[asterisk-security] AST-2019-004: Crash when negotiating for T.38 with a declined stream

Sun Sep 8 23:07:19 CDT 2019

Maybe:

T.38 Gateway Fax Activity Timeout

By default, gateway mode will remain enabled throughout the life of a channel. An optional timeout can be enabled to automatically disable gateway mode if there is no fax activity a given time after two channels are bridged. Enabling a timeout also has the side effect of reserving fax resources for a channel. The timeout can be enabled by passing second parameter (a timeout in seconds) when setting FAXOPT(gateway).

exten => 1,1,NoOp()
exten => 1,n,Set(FAXOPT(gateway)=yes,10) ; disable gateway if there is no fax activity in 10 seconds
exten => 1,n,Dial(SIP/mypeer,20)

Krystyna Haberek

-----Original Message-----
From: asterisk-security <asterisk-security-bounces at lists.digium.com> On Behalf Of Asterisk Security Team
Sent: September 5, 2019 7:50 AM
To: asterisk-security at lists.digium.com
Subject: [asterisk-security] AST-2019-004: Crash when negotiating for T.38 with a declined stream

               Asterisk Project Security Advisory - AST-2019-004

         Product        Asterisk                                              
         Summary        Crash when negotiating for T.38 with a declined       
                        stream                                                
    Nature of Advisory  Remote Crash                                          
      Susceptibility    Remote Authenticated Sessions                         
         Severity       Minor                                                 
      Exploits Known    No                                                    
       Reported On      August 05, 2019                                       
       Reported By      Alexei Gradinari                                      
        Posted On       September 05, 2019                                    
     Last Updated On    September 4, 2019                                     
     Advisory Contact   kharwell AT sangoma DOT com                           
         CVE Name       CVE-2019-15297                                        

      Description     When Asterisk sends a re-invite initiating T.38         
                      faxing, and the endpoint responds with a declined       
                      media stream a crash will then occur in Asterisk.       
    Modules Affected  res_pjsip_t38.c                                         

    Resolution  If T.38 faxing is not required then setting the ???t38_udptl???   
                configuration option on the endpoint to ???no??? disables this    
                functionality. This option defaults to ???no??? so you have to    
                have explicitly set it ???yes??? to potentially be affected by    
                this issue.                                                   

                Otherwise, if T.38 faxing is required then Asterisk should    
                be upgraded to a fixed version.                               

                               Affected Versions
                Product              Release Series  
         Asterisk Open Source             15.x       All releases             
         Asterisk Open Source             16.x       All releases             

                                  Corrected In
                    Product                              Release              
             Asterisk Open Source                     15.7.4,16.5.1           

                                    Patches                        
                               SVN URL                              Revision  
   https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdownloads.asterisk.org%2Fpub%2Fsecurity%2FAST-2019-004-15.diff&data=02%7C01%7C%7C48c632173e4645d2677b08d7321121c5%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637032921465083334&sdata=3tpojkhZW5la529mGa3UMpORgf9nxB01pozoVymEc1o%3D&reserved=0 Asterisk   
                                                                   15         
   https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdownloads.asterisk.org%2Fpub%2Fsecurity%2FAST-2019-004-16.diff&data=02%7C01%7C%7C48c632173e4645d2677b08d7321121c5%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637032921465083334&sdata=tg43YzaI%2BieB5829LIY%2FS8vi%2BH2lD8sR6rB61%2Bburiw%3D&reserved=0 Asterisk   
                                                                   16         

       Links     https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fissues.asterisk.org%2Fjira%2Fbrowse%2FASTERISK-28495&data=02%7C01%7C%7C48c632173e4645d2677b08d7321121c5%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637032921465083334&sdata=obuonOONUAmqFNh34UHpjMm%2BkCPLELAf%2FnMFaTUTtY0%3D&reserved=0       

    Asterisk Project Security Advisories are posted at                        
    https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.asterisk.org%2Fsecurity&data=02%7C01%7C%7C48c632173e4645d2677b08d7321121c5%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637032921465083334&sdata=10ZZ2QY%2Bze2m3U04%2BEQYcUmM2ilTxw229MpcXa4U4FY%3D&reserved=0                                          

    This document may be superseded by later versions; if so, the latest      
    version will be posted at                                                 
    https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdownloads.digium.com%2Fpub%2Fsecurity%2FAST-2019-004.pdf&data=02%7C01%7C%7C48c632173e4645d2677b08d7321121c5%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637032921465083334&sdata=MO63HCsGtSQ6MRfzcJQUWxaVFOz0TjSi8HDVupbr3D8%3D&reserved=0 and             
    https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdownloads.digium.com%2Fpub%2Fsecurity%2FAST-2019-004.html&data=02%7C01%7C%7C48c632173e4645d2677b08d7321121c5%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637032921465083334&sdata=%2FNSziKGde8Bl1ImkkucQCj2pN%2BRG1E2GdRCk1tgCmTI%3D&reserved=0                

                                Revision History
          Date                  Editor                 Revisions Made         
    August 28, 2019    Kevin Harwell             Initial revision             

               Asterisk Project Security Advisory - AST-2019-004
               Copyright ?? 2019 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.