Denial of service in systemd

1) Uncontrolled recursion

EUVDB-ID: #VU59358

Risk: Low

CVSSv4.0: 5.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:U/U:Clear]

CVE-ID: CVE-2021-3997

CWE-ID: CWE-674 - Uncontrolled Recursion

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to uncontrolled recursion in systemd-tmpfiles. A local user can create multiple nested directories in the /tmp folder and case systemd to crash during the system boot.

Mitigation

Install update from vendor's website.

Vulnerable software versions

systemd: 241 - 250.1

CPE2.3

• cpe:2.3:a:freedesktop_org:systemd:241:*:*:*:*:*:*:*
• cpe:2.3:a:freedesktop_org:systemd:242:rc1:*:*:*:*:*:*
• cpe:2.3:a:freedesktop_org:systemd:242:rc2:*:*:*:*:*:*

External links

https://seclists.org/oss-sec/2022/q1/18
https://github.com/systemd/systemd/commit/55a89ea1b4088a6d84ba0bd3cd8e648bd51f1ebf

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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