Vulnerability identifier: #VU61423

Vulnerability risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-0396

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ISC BIND
Server applications / DNS servers

Vendor: ISC

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper management of internal resources within the application that allows TCP connection slots to be consumed for an indefinite time frame via a specifically crafted TCP stream sent from a client. A remote attacker can initiate a specially crafted TCP stream that 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.

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.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.11.0 - 9.18.0

---

External links
http://kb.isc.org/docs/cve-2022-0396

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.