Posting date: 12 April 2017
9.8.0 -> 9.8.8-P1, 9.9.0 -> 9.9.9-P6, 9.9.10b1->9.9.10rc1, 9.10.0 -> 9.10.4-P6, 9.10.5b1->9.10.5rc1, 9.11.0 -> 9.11.0-P3, 9.11.1b1->9.11.1rc1, 9.9.3-S1 -> 9.9.9-S8
Medium, but only a risk to systems with specific configurations
A query with a specific set of characteristics could cause a server using DNS64 to encounter an assertion failure and terminate.
An attacker could deliberately construct a query, enabling denial-of-service against a server if it was configured to use the DNS64 feature and other preconditions were met.
Servers are at risk if they are configured to use DNS64 and if the option "break-dnssec yes;" is in use.
CVSS Score: 5.9
CVSS Vector: CVSS:3.0/AV:N/AC:H/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:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Servers which have configurations which require DNS64 and "break-dnssec yes;" should upgrade. Servers which are not using these features in conjunction are not at risk from this defect.
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.
New maintenance releases of BIND are also
scheduled which contain the fix for this vulnerability. In addition to
the security releases listed above, fixes for this vulnerability are
also included in these release candidate versions:
- BIND 9 version 9.9.10rc3
- BIND 9 version 9.10.5rc3
- BIND 9 version 9.11.1rc3
Acknowledgements: ISC would like to thank Oleg Gorokhov of Yandex for making us aware of this vulnerability.
Document Revision History:
1.0 Advance Notification 08 March 2017
1.1 Revised Publication Date; Added pre-releases to Versions Affected 20 March 2017
2.0 Public Announcement 12 April 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.
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 firstname.lastname@example.org. To report a new issue, please encrypt your message using email@example.com's PGP key which can be found here: https://www.isc.org/downloads/software-support-policy/openpgp-key/. 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 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-01465 is the complete and official security advisory document.
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