CVE-2013-3919: A recursive resolver can be crashed by a query for a malformed zone

Michael McNally mcnally at
Tue Jun 4 23:53:14 UTC 2013

A defect exists which allows an attacker to crash a BIND 9 recursive
resolver with a RUNTIME_CHECK error in resolver.c

CVE:                    CVE-2013-3919
Document Version:       1.0
Posting date:           04 Jun 2013
Program Impacted:       BIND 9

Versions affected: 

   BIND 9.6-ESV-R9, 9.8.5, and 9.9.3 are affected

   Versions 9.6.0 through 9.6-ESV-R8, 9.8.0 through 9.8.4-P2, and
   9.9.0 through 9.9.2-P2 ARE NOT affected.

   Other major branches of BIND (e.g. 9.7, 9.5, etc) are not
   vulnerable but they are no longer supported by ISC and may lack
   other important security fixes.

Severity:               High
Exploitable:            Remotely


   A bug has been discovered in the most recent releases of BIND 9
   which has the potential for deliberate exploitation as a
   denial-of-service attack. By sending a recursive resolver a query
   for a record in a specially malformed zone, an attacker can cause
   BIND 9 to exit with a fatal "RUNTIME_CHECK" error in resolver.c


   Triggering this defect will cause the affected server to exit
   with an error, denying service to recursive DNS clients that use
   that particular server.

CVSS Score:  7.8

CVSS Equation:  (AV:N/AC:L/Au:N/C:N/I:N/A:C)

For more information on the Common Vulnerability Scoring System and
to obtain your specific environmental score please visit:

Workarounds:            None.

Active exploits:

   At the time of this advisory no intentional exploitation of this
   bug has been observed in the wild. However, the existence of the
   issue has been disclosed on an open mailing list with enough
   accompanying detail to reverse engineer an attack and ISC is
   therefore treating this as a Type II (publicly disclosed)
   vulnerability, in accordance with our Phased Disclosure Process.


   New versions of BIND are being provided which contain a fix for
   the defect. The recommended solution is to upgrade to the patched
   release most closely related to your current version of BIND.
   These can all be downloaded from

    -  BIND 9 version 9.9.3-P1
    -  BIND 9 version 9.8.5-P1
    -  BIND 9 version 9.6-ESV-R9-P1


Document Revision History:

   1.0 Type II Public Disclosure, 04 June, 2013

Related Documents:

   See our BIND Security Matrix for a complete listing of Security
   Vulnerabilities and versions affected.

   If you'd like more information on our product support please

Do you still have questions?  Questions regarding this advisory
should go to security-officer at

Note: ISC patches only currently supported versions. When possible
we indicate EOL versions affected.

ISC Security Vulnerability Disclosure Policy: 

   Details of our current security advisory policy and practice can
   be found here: ISC Software Defect and Security Vulnerability
   Disclosure Policy

This Knowledge Base article is
the complete and official security advisory document.

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