CVE-2016-8864: A problem handling responses containing a DNAME
answer can lead to an assertion failure
CVE: CVE-2016-8864
Document Version: 2.0
Posting date: 1 November 2016
Program Impacted: BIND
Versions affected: 9.0.x -> 9.8.x, 9.9.0 -> 9.9.9-P3,
9.9.3-S1 -> 9.9.9-S5, 9.10.0 -> 9.10.4-P3,
9.11.0
Severity: High
Exploitable: Remotely
Description:
A defect in BIND's handling of responses containing a DNAME answer
can cause a resolver to exit after encountering an assertion failure
in db.c or resolver.c
Impact:
During processing of a recursive response that contains a DNAME
record in the answer section, BIND can stop execution after
encountering an assertion error in resolver.c (error message:
"INSIST((valoptions & 0x0002U) != 0) failed") or db.c (error
message: "REQUIRE(targetp != ((void *)0) && *targetp == ((void
*)0)) failed").
ther of these error conditions will stop,
resulting in denial of service to clients. The risk to authoritative
servers is minimal; recursive servers are chiefly at risk.
CVSSv3 Score: 7.5
CVSSv3 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 but a query which could trigger the crash
was briefly discussed on a public mailing list before the domain
owner pulled the record causing the problem.
Solution:
Upgrade to the patched release most closely related to your current
version of BIND.
- BIND 9 version 9.9.9-P4
- BIND 9 version 9.10.4-P4
- BIND 9 version 9.11.0-P1
BIND 9 Supported Preview edition is a feature preview version of BIND
provided exclusively to eligible ISC Support customers.
- BIND 9 version 9.9.9-S6
Acknowledgements:
ISC would like to thank Tony Finch (University of Cambridge), Marco
Davids (SIDN Labs) and others for reporting and extending our
understanding of the issue.
Document Revision History:
1.0 Advance Notification 21 October, 2016
1.1 Updated versions affected; Updated Acknowledgements. 27 October,
2016
2.0 Public Announcement, 1 November, 2016
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/.
Do you still have questions? Questions regarding this advisory
should go to security-offi...@isc.org. To report a new issue,
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If you are unable to use encrypted email, you may also report new
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 Disclos 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-01434 is
the complete and official security advisory document.
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