Vulnerability identifier: #VU84797

Vulnerability risk: Medium

CVSSv3.1: 6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:U/RC:C]

CVE-ID: CVE-2023-51765

CWE-ID: CWE-77

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Sendmail
Server applications / Mail servers

Vendor: Proofpoint

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

Vulnerable software versions

Sendmail: 2.6 - 8.17.2

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External links
http://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/
http://www.openwall.com/lists/oss-security/2023/12/22/7
http://www.openwall.com/lists/oss-security/2023/12/21/7
http://github.com/freebsd/freebsd-src/commit/5dd76dd0cc19450133aa379ce0ce4a68ae07fb39#diff-afdf514b32ac88004952c11660c57bc96c3d8b2234007c1cbd8d7ed7fd7935cc
http://www.openwall.com/lists/oss-security/2023/12/24/1
http://www.openwall.com/lists/oss-security/2023/12/25/1
http://bugzilla.suse.com/show_bug.cgi?id=1218351
http://bugzilla.redhat.com/show_bug.cgi?id=2255869
http://access.redhat.com/security/cve/CVE-2023-51765
http://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html
http://www.openwall.com/lists/oss-security/2023/12/26/5

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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.