MitM attack in libgit2

1) Configuration

EUVDB-ID: #VU71412

Risk: Low

CVSSv4.0: 0.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2023-22742

CWE-ID: CWE-16 - Configuration

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to missing certificate validation in libgit2, when compiled using the optional, included libssh2 backend. Prior versions of libgit2 require the caller to set the certificate_check field of libgit2's git_remote_callbacks structure - if a certificate check callback is not set, libgit2 does not perform any certificate checking. This means that by default - without configuring a certificate check callback, clients will not perform validation on the server SSH keys and may be subject to a man-in-the-middle attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

libgit2: 1.4.0 - 1.5.0

CPE2.3

• cpe:2.3:a:libgit2_github_com:libgit2:1.4.4:*:*:*:*:*:*:*
• cpe:2.3:a:libgit2_github_com:libgit2:1.5.0:*:*:*:*:*:*:*

External links

https://github.com/libgit2/libgit2/releases/tag/v1.4.5
https://github.com/libgit2/libgit2/releases/tag/v1.5.1
https://github.com/libgit2/libgit2/security/advisories/GHSA-8643-3wh5-rmjq

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.