Vulnerability identifier: #VU23425

Vulnerability risk: Low

CVSSv3.1: 7.4 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C]

CVE-ID: CVE-2019-19522

CWE-ID: CWE-399

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
OpenBSD
Operating systems & Components / Operating system

Vendor: OpenBSD

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to an error in authentication process, where S/Key or YubiKey authentication is enabled. A local user can gain root privileges by leveraging membership in the auth group. This occurs because root's file can be written to /etc/skey or /var/db/yubikey, and need not be owned by root.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

OpenBSD: 6.6

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External links
http://www.openwall.com/lists/oss-security/2019/12/04/5
http://seclists.org/bugtraq/2019/Dec/8
http://www.openbsd.org/errata66.html
http://www.openwall.com/lists/oss-security/2019/12/04/5

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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. However, proof of concept for this vulnerability is available.