Authentication bypass in OpenVPN

1) Improper Authentication

EUVDB-ID: #VU61608

Risk: Medium

CVSSv3.1: 4.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-0547

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error when processing authentication requests in external authentication plug-ins when more than one of them makes use of deferred authentication replies. A remote attacker can bypass authentication process and gain unauthorized access to the network with only partially correct credentials.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

OpenVPN: 2.1 - 2.5.5

External links

http://community.openvpn.net/openvpn/wiki/SecurityAnnouncements
http://community.openvpn.net/openvpn/wiki/CVE-2022-0547

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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