CVE-2022-3736: named configured to answer from stale cache may terminate unexpectedly while processing RRSIG queries

CVE: CVE-2022-3736

Document version: 2.0

Posting date: 25 January 2023

Program impacted: BIND 9

Versions affected:

BIND

• 9.16.12 -> 9.16.36
• 9.18.0 -> 9.18.10
• 9.19.0 -> 9.19.8

BIND Supported Preview Edition

• 9.16.12-S1 -> 9.16.36-S1

(The flaw exists in the implementation of the stale-answer-client-timeout option, which was first effectively introduced in BIND 9.16.12 and BIND 9.16.12-S1. That option is also configurable in BIND 9.11.33-S1 and newer BIND 9.11-S versions, but it is always replaced with 0 in all BIND 9.11.x-S1 releases.)

Severity: High

Exploitable: Remotely

Description:

BIND 9 resolver can crash when stale cache and stale answers are enabled, option stale-answer-client-timeout is set to a positive integer, and the resolver receives an RRSIG query.

Impact:

By sending specific queries to the resolver, an attacker can cause named to crash.

CVSS Score: 7.5

CVSS Vector: CVSS:3.1/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://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H&version=3.1.

Workarounds:

Setting stale-answer-client-timeout to 0 or to off/disabled will prevent BIND from crashing due to this issue.

Active exploits:

We are not aware of any active exploits.

Solution:

Upgrade to the patched release most closely related to your current version of BIND 9:

• 9.16.37
• 9.18.11
• 9.19.9

BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers.

• 9.16.37-S1

Acknowledgments:

ISC would like to thank Borja Marcos from Sarenet (with assistance by Iratxe Niño from Fundación Sarenet) for bringing this vulnerability to our attention.

Document revision history:

• 1.0 Early Notification, 18 January 2023
• 2.0 Public disclosure, 25 January 2023

Related documents:

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 be mailed to security-officer@isc.org. To report a new issue, please encrypt your message using security-officer@isc.org's PGP key, which can be found here: https://www.isc.org/pgpkey/. If you are unable to use encrypted email you may also report new issues at: https://www.isc.org/reportbug/.

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 https://www.isc.org/download/.

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 at https://kb.isc.org/docs/aa-00861.

The Knowledgebase article https://kb.isc.org/docs/cve-2022-3736 is the complete and official security advisory document.

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