Vulnerability identifier: #VU28192

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-12823

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenConnect VPN Client
Client/Desktop applications / Other client software

Vendor: OpenConnect

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

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

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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.