Denial of service in Knot Resolver

1) Resource exhaustion

EUVDB-ID: #VU78292

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2022-40188

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

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

The vulnerability exists due to application does not properly control consumption of internal resources caused by algorithmic complexity. A malicious authoritative server can return large NS sets or addresses and cause excessive CPU consumption. 

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Knot Resolver: 5.5.0 - 5.5.2

CPE2.3

• cpe:2.3:a:nic:knot_resolver:5.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:nic:knot_resolver:5.5.1:*:*:*:*:*:*:*
• cpe:2.3:a:nic:knot_resolver:5.5.2:*:*:*:*:*:*:*

External links

https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1343#note_262558
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/S2VE5K3VDUHJOIA2IGT3G5R76IBADMNE/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HIMDNIUI7GTUEKIBBYYW7OCTJQFPDNXL/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XO6LIVQS62MI5GG4OVYB5RHVZMYNHAHG/
https://lists.debian.org/debian-lts-announce/2022/10/msg00008.html

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.