Signature validation bypass in OpenDKIM

1) Security features bypass

EUVDB-ID: #VU83527

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2022-48521

CWE-ID: CWE-254 - Security Features

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass implemented security measures.

The vulnerability exists due to improper tracking of ordinal numbers when removing fake Authentication-Results header fields. A remote attacker can create a specially crafted e-mail message with a fake sender address that will be treated as a message having a valid DKIM signature by software that relies on Authentication-Results from OpenDKIM.

Mitigation

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

Vulnerable software versions

opendkim: 2.2.2 - 2.11.0 Beta2

CPE2.3

• cpe:2.3:a:www.opendkim.org:opendkim:2.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:www.opendkim.org:opendkim:2.3.0:Beta0:*:*:*:*:*:*
• cpe:2.3:a:www.opendkim.org:opendkim:2.3.0:Beta1:*:*:*:*:*:*

External links

https://github.com/trusteddomainproject/OpenDKIM/issues/148
https://bugzilla.redhat.com/show_bug.cgi?id=2223352
https://bugzilla.redhat.com/show_bug.cgi?id=2223270

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.