CVE-2022-0396: CVE-2022-0396: DoS from specifically crafted TCP packets - Security Advisories

CVE: CVE-2022-0396

Document version: 2.0

Posting date: 16 March 2022

Program impacted: BIND

Versions affected: BIND 9.16.11 -> 9.16.26, 9.17.0 -> 9.18.0 and versions 9.16.11-S1 -> 9.16.26-S1 of the BIND Supported Preview Edition.

Severity: Medium

Exploitable: Remotely

Description:

ISC recently discovered an issue in BIND that allows TCP connection slots to be consumed for an indefinite time frame via a specifically crafted TCP stream sent from a client. This issue is present in BIND 9.16.11 to 9.16.26 (including S editions), and 9.18.0.

This issue can only be triggered on BIND servers which have keep-response-order enabled, which is not the default configuration. The keep-response-order option is an ACL block; any hosts which are specified within it will be able to trigger this issue on affected versions.

Impact:

Specifically crafted TCP streams can cause connections to BIND to remain in CLOSE_WAIT status for an indefinite period of time, even after the client has terminated the connection.

CVSS Score: 4.9

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:F/RL:O/RC:C

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:L/E:F/RL:O/RC:C&version=3.1.

Workarounds:

To mitigate this issue in all affected versions of BIND, use the default setting of keep-response-order { none; }.

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:

• 9.16.27
• 9.18.1

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

• 9.16.27-S1

Document revision history:

1.0 Early Notification, 9 March 2022
1.1 Grammatical edit to Description, 16 March 2022
2.0 Public disclosure, 16 March 2022

Related documents:

See CVE-2019-6477: TCP-pipelined queries can bypass tcp-clients limit for more information regarding CVE-2019-6477, in which ISC recommended setting keep-response-order to any to work around a previous issue where BIND was not respecting the TCP client limit.

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/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-2022-0396 is the complete and official security advisory document.

Legal Disclaimer:

Internet Systems Consortium (ISC) is providing this notice on an “AS IS” basis. No warranty or guarantee of any kind is expressed in this notice and none should be implied. ISC expressly excludes and disclaims any warranties regarding this notice or materials referred to in this notice, including, without limitation, any implied warranty of merchantability, fitness for a particular purpose, absence of hidden defects, or of non-infringement. Your use or reliance on this notice or materials referred to in this notice is at your own risk. ISC may change this notice at any time. A stand-alone copy or paraphrase of the text of this document that omits the document URL is an uncontrolled copy. Uncontrolled copies may lack important information, be out of date, or contain factual errors.