Signature spoofing attack in GnuPG

1) Improper Verification of Cryptographic Signature

EUVDB-ID: #VU64909

Risk: Medium

CVSSv3.1: 5.4 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:U/RC:C]

CVE-ID: CVE-2022-34903

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to an error in GnuPG, which allows signature spoofing via arbitrary injection into the status line. A remote attacker who controls the secret part of any signing-capable key or subkey in the victim's keyring, can take advantage of this flaw to provide a correctly-formed signature that some software, including gpgme, will accept to have validity and signer fingerprint chosen from the attacker.

Mitigation

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

Vulnerable software versions

GnuPG: 2.2 - 2.3.6

External links

http://dev.gnupg.org/T6027
http://bugs.debian.org/1014157
http://www.openwall.com/lists/oss-security/2022/06/30/1
http://www.openwall.com/lists/oss-security/2022/07/02/1
http://www.debian.org/security/2022/dsa-5174

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.