Posting date: 12 April 2017
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
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.
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
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
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
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 email@example.com. To report a new issue, please encrypt your message using firstname.lastname@example.org'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-01466 is the complete and official security advisory document.
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