CVE-2017-3137: A response packet can cause a resolver to terminate when processing an answer containing a CNAME or DNAME
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
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.
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 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 BIND 9 Security Vulnerability Matrix for a complete listing of Security Vulnerabilities and versions affected.
Do you still have questions? Questions regarding this advisory should go to [email protected]. To report a new issue, please encrypt your message using [email protected]'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/.
ISC patches only currently supported versions. When possible we indicate EOL versions affected. (For current information on which versions are actively supported, please see https://www.isc.org/downloads/).
ISC Security Vulnerability Disclosure Policy:
Details of our current security advisory policy and practice can be found in the ISC Software Defect and Security Vulnerability Disclosure Policy.
This Knowledgebase article is the complete and official security advisory document.
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