CVE-2016-9131: A malformed response to an ANY query can cause an assertion failure during recursion

[Michael McNally]

CVE:                    CVE-2016-9131
Document Version:       2.0
Posting date:           11 Jan 2017
Program Impacted:       BIND
Versions affected:      9.4.0 -> 9.6-ESV-R11-W1, 9.8.5 -> 9.8.8,
                        9.9.3 -> 9.9.9-P4, 9.9.9-S1 -> 9.9.9-S6,
                        9.10.0 -> 9.10.4-P4, 9.11.0 -> 9.11.0-P1
Severity:               High
Exploitable:            Remotely

Description:

   A malformed query response received by a recursive server in
   response to a query of RTYPE ANY could trigger an assertion
   failure while named is attempting to add the RRs in the query
   response to the cache.  While 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 having the required properties, after having engineered
   a scenario whereby an ANY query is sent to the recursive server
   for the target QNAME.  A recursive server will itself only send
   a query of type ANY if it receives a client query of type ANY
   for a QNAME for which it has no RRsets at all in cache, otherwise
   it will respond to the client with the the RRsets that it has
   available.

Impact:

   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
   https://kb.isc.org/article/AA-00914).

   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

For more information on the Common Vulnerability Scoring System and
to obtain your specific environmental score please visit:
https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Workarounds:

   The use of external packet filtering to drop client queries of
   RTYPE=ANY should prevent exploitation of this vulnerability.

Active exploits:

   No known active exploits.

Solution:

   Upgrade to the patched release most closely related to your
   current version of BIND. These can all be downloaded from
   http://www.isc.org/downloads.

     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
   2.0 Public Announcement, 11 January 2017

Related Documents:

   See our BIND9 Security Vulnerability Matrix at
   https://kb.isc.org/article/AA-00913 for a complete listing of
   Security Vulnerabilities and versions affected

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Note:

   ISC patches only currently supported versions. When possible we
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   which versions are actively supported, please see
   http://www.isc.org/downloads/).

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https://kb.isc.org/article/AA-00861/164/ISC-Software-Defect-and-Security-Vulnerability-Disclosure-Policy.html

This Knowledge Base article https://kb.isc.org/article/AA-01439 is
the complete and official security advisory document.

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