CVE-2022-2906: CVE-2022-2906 Memory Leak in DH Code

CVE-2022-2906: Memory leaks in code handling Diffie-Hellman key exchange via TKEY RRs (OpenSSL 3.0.0+ only)

• Updated on 21 Sep 2022
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CVE: CVE-2022-2906

Document version: 2.0

Posting date: 21 September 2022

Program impacted: BIND

Versions affected:

BIND

• 9.18.0 -> 9.18.6
• 9.19.0 -> 9.19.4

BIND Supported Preview Edition

• None

Severity: High

Exploitable: Remotely

Description:

Changes between OpenSSL 1.x and OpenSSL 3.0 expose a flaw in named that causes a small memory leak in key processing when using TKEY records in Diffie-Hellman mode with OpenSSL 3.0.0 and later versions.

Impact:

An attacker can leverage this flaw to gradually erode available memory to the point where named crashes for lack of resources. Upon restart the attacker would have to begin again, but nevertheless there is the potential to deny service.

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:

There are no known workarounds. TKEY record processing in GSS-TSIG mode is not affected by this defect. The memory leak impacts authoritative DNS server TKEY record processing only. Client processing (resolver functions) do not trigger this defect.

Active exploits:

This flaw was discovered in internal testing. We are not aware of any active exploits.

Solution:

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

• 9.18.7
• 9.19.5

The flaw does not affect any versions of BIND prior to 9.18, including BIND 9.16-S.

Document revision history:

1.0 Early Notification, 14 September 2022
1.1 Minor punctuation corrections, 19 September 2022
2.0 Public disclosure, 21 September 2022

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 [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/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-2022-2906 is the complete and official security advisory document.

Legal Disclaimer:

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