CVE-2024-1975: SIG(0) can be used to exhaust CPU resources

CVE: CVE-2024-1975

Title: SIG(0) can be used to exhaust CPU resources

Document version: 2.0

Posting date: 23 July 2024

Program impacted: BIND 9

Versions affected:

BIND

• 9.0.0 -> 9.11.37
• 9.16.0 -> 9.16.50
• 9.18.0 -> 9.18.27
• 9.19.0 -> 9.19.24

(Versions prior to 9.16.48 were not assessed.)

BIND Supported Preview Edition

• 9.9.3-S1 -> 9.11.37-S1
• 9.16.8-S1 -> 9.16.49-S1
• 9.18.11-S1 -> 9.18.27-S1

(Versions prior to 9.16.48-S1 were not assessed.)

Severity: High

Exploitable: Remotely

Description:

If a server hosts a zone containing a "KEY" Resource Record, or a resolver DNSSEC-validates a "KEY" Resource Record from a DNSSEC-signed domain in cache, a client can exhaust resolver CPU resources by sending a stream of SIG(0) signed requests.

Impact:

Depletion of available CPU resources may cause BIND to become unresponsive.

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:

No workarounds known.

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:

• 9.18.28
• 9.20.0

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

• 9.18.28-S1

Document revision history:

• 1.0 Early Notification, 10 July 2024
• 1.1 Revised public disclosure date, 16 July 2024
• 2.0 Public disclosure, 23 July 2024

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 bind-security@isc.org or posted as confidential GitLab issues at https://gitlab.isc.org/isc-projects/bind9/-/issues/new?issue[confidential]=true.

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-2024-1975 is the complete and official security advisory document.

Legal Disclaimer:

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