Remote code execution in OpenConnect VPN client

1) Buffer overflow

EUVDB-ID: #VU28192

Risk: Medium

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-12823

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary within the get_cert_name() function in gnutls.c. A remote attacker can trick the victim to connect to a malicious VPN server, trigger buffer overflow and crash the client or execute arbitrary code on the system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

OpenConnect VPN Client: 3.99 - 8.09

CPE2.3

• cpe:2.3:a:openconnect:openconnect:3.99:*:*:*:*:*:*:*
• cpe:2.3:a:openconnect:openconnect:4.00:*:*:*:*:*:*:*
• cpe:2.3:a:openconnect:openconnect:4.01:*:*:*:*:*:*:*

External links

https://bugs.gentoo.org/721570
https://gitlab.com/openconnect/openconnect/-/merge_requests/108
https://lists.debian.org/debian-lts-announce/2020/05/msg00015.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/AYSXLXAPXD2T73T6JMHI5G2WP7KHAGMN/

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.