Posting date: 11 Jan 2017
9.9.9-P4, 9.9.9-S6, 9.10.4-P4, 9.11.0-P1
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
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-00914/55/Why-does-my-authoritative-only-nameserver-try-to-query-the-root-nameservers.html). 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.
exploitation of this vulnerability will cause named to encounter an
assertion failure and stop executing, resulting in denial of service to
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
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.
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
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 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-00861/164/ISC-Software-Defect-and-Security-Vulnerability-Disclosure-Policy.html
This Knowledge Base article https://kb.isc.org/article/AA-01440 is the complete and official security advisory document.
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