CVE-2016-9147: An error handling a query response containing inconsistent DNSSEC information could cause an assertion failure bind

Michael McNally mcnally at
Wed Jan 11 22:35:25 UTC 2017

CVE:                    CVE-2016-9147
Document Version:       2.0
Posting date:           11 Jan 2017
Program Impacted:       BIND
Versions affected:      9.9.9-P4, 9.9.9-S6, 9.10.4-P4, 9.11.0-P1
Severity:               High
Exploitable:            Remotely


   Depending on the type of query and the EDNS options in the query
   they receive, DNSSEC-enabled authoritative servers are expected
   to include RRSIG and other RRsets in their responses to recursive
   servers.  DNSSEC-validating servers will also make specific
   queries for DS and other RRsets.  Whether DNSSEC-validating or
   not, an error in processing malformed query responses that
   contain DNSSEC-related RRsets that are inconsistent with other
   RRsets in the same query response can trigger an assertion
   failure.  Although the combination of properties which triggers
   the assertion should not occur in normal traffic, it is potentially
   possible for the assertion to be triggered deliberately by an
   attacker sending a specially-constructed answer.


   This vulnerability occurs during the processing of an answer
   packet received in response to a query.  As a result, recursive
   servers are at the greatest risk; authoritative servers are at
   risk only to the extent that they perform a limited set of queries
   (for example, in order to do zone service - see
   There are several variations of malformed query response that
   can cause an assertion failure, some of which will trigger a
   failure on recursive servers that are not DNSSEC-validating.

   Successful exploitation of this vulnerability will cause named
   to encounter an assertion failure and stop executing, resulting
   in denial of service to clients.

CVSS Score:             7.5
CVSS Vector:            CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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   None known.

Active exploits:

   No known active exploits.


   Upgrade to the patched release most closely related to your
   current version of BIND. These can all be downloaded from

     BIND 9 version 9.9.9-P5
     BIND 9 version 9.10.4-P5
     BIND 9 version 9.11.0-P2

BIND Supported Preview Edition is a special feature preview branch
of BIND provided to eligible ISC support customers.

     BIND 9 version 9.9.9-S7

Document Revision History:

   1.0 Advance Notification, 03 January 2017
   1.1 Updated Versions affected to include 9.9.9-S6 and Solution to
include 9.9.9-S7, 09 January 2017
   2.0 Public Announcement, 11 January 2017

Related Documents:

   See our BIND9 Security Vulnerability Matrix at for a complete listing of
   Security Vulnerabilities and versions affected.

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