CVE-2017-3137: A response packet can cause a resolver to terminate when processing an answer containing a CNAME or DNAME

[Michael McNally]

CVE:                 CVE-2017-3137
Document Version:    2.0
Posting date:        12 April 2017
Program Impacted:    BIND
Versions affected:   9.9.9-P6, 9.9.10b1->9.9.10rc1, 9.10.4-P6,
                     9.10.5b1->9.10.5rc1, 9.11.0-P3, 9.11.1b1->9.11.1rc1,
                     and 9.9.9-S8
Severity:            High
Exploitable:         Remotely

Description:

   Mistaken assumptions about the ordering of records in the answer
   section of a response containing CNAME or DNAME resource records
   could lead to a situation in which named would exit with an
   assertion failure when processing a response in which records
   occurred in an unusual order.

Impact:

   A server which is performing recursion can be forced to exit
   with an assertion failure if it can be caused to receive a
   response containing CNAME or DNAME resource records with certain
   ordering.  An attacker can cause a denial of service by exploiting
   this condition.  Recursive resolvers are at highest risk but
   authoritative servers are theoretically vulnerable if they perform
   recursion.

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:

   None known.

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-P8
   -  BIND 9 version 9.10.4-P8
   -  BIND 9 version 9.11.0-P5

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

   -  BIND 9 version 9.9.9-S10

   New development releases of BIND are also available which contain
   the fix for this vulnerability:

   -  BIND 9 version 9.9.10rc3
   -  BIND 9 version 9.10.5rc3
   -  BIND 9 version 9.11.1rc3

Document Revision History:

   1.0 Advance Notification 08 March 2017
   1.1 Revised Posting Date; Added pre-releases to Versions Affected
       20 March 2017
   1.2 Revised patch release versions 12 April 2017
   2.0 Public Announcement 12 April 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.If you'd like
   more information on ISC Subscription Support and Advance Security
   Notifications, please visit http://www.isc.org/support/.

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should go to security-officer at isc.org.  To report a new issue,
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issues at: https://www.isc.org/community/report-bug/.

Note:

   ISC patches only currently supported versions. When possible we
   indicate EOL versions affected.  (For current information on which
   versions are actively supported, please see
http://www.isc.org/downloads/).

ISC Security Vulnerability Disclosure Policy:

   Details of our current security advisory policy and practice can
   be found here: https://kb.isc.org/article/AA-00861

This Knowledge Base article https://kb.isc.org/article/AA-01466 is
the complete and official security advisory document.

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