#VU84727 Command Injection in Postfix - CVE-2023-51764

Vulnerability identifier: #VU84727

Vulnerability risk: Medium

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2023-51764

CWE-ID: CWE-77

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Postfix
Server applications / Mail servers

Vendor: Postfix.org

Description

The vulnerability allows a remote attacker to spoof email messages.

The vulnerability exists due to an error when handling line endings other than <CR><LF>. A remote attacker can spoof contents of email message and bypass SPF protection mechanism.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Postfix: 3.0.0 - 3.8.3

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External links
https://www.postfix.org/smtp-smuggling.html
https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/
https://www.openwall.com/lists/oss-security/2023/12/24/1

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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. However, proof of concept for this vulnerability is available.