CWE
345
Advisory Published
CVE Published
Updated

CVE-2023-51764

First published: Thu Dec 21 2023(Updated: )

Postfix through 3.8.5 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports <LF>.<CR><LF> but some other popular e-mail servers do not. To prevent attack variants (by always disallowing <LF> without <CR>), a different solution is required, such as the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.

Credit: cve@mitre.org cve@mitre.org

Affected SoftwareAffected VersionHow to fix
debian/postfix<=3.8.2-1<=3.4.23-0+deb10u1<=3.7.6-0+deb12u2<=3.5.18-0+deb11u1
3.8.4-1
3.7.9-0+deb12u1
3.5.23-0+deb11u1
Postfix Postfix<3.5.23
Postfix Postfix>=3.6.0<3.6.13
Postfix Postfix>=3.7.0<3.7.9
Postfix Postfix>=3.8.0<3.8.4
Fedoraproject Fedora=38
Fedoraproject Fedora=39
Redhat Enterprise Linux=8.0
Redhat Enterprise Linux=9.0
redhat/postfix<3.8.4
3.8.4
redhat/postfix<3.7.9
3.7.9
redhat/postfix<3.6.13
3.6.13
redhat/postfix<3.5.23
3.5.23
ubuntu/postfix<3.3.0-1ubuntu0.4+
3.3.0-1ubuntu0.4+
ubuntu/postfix<3.4.13-0ubuntu1.4
3.4.13-0ubuntu1.4
ubuntu/postfix<3.6.4-1ubuntu1.3
3.6.4-1ubuntu1.3
ubuntu/postfix<3.8.1-2ubuntu0.2
3.8.1-2ubuntu0.2
ubuntu/postfix<2.11.0-1ubuntu1.2+
2.11.0-1ubuntu1.2+
ubuntu/postfix<3.8.4-1
3.8.4-1
ubuntu/postfix<3.1.0-3ubuntu0.4+
3.1.0-3ubuntu0.4+
debian/postfix<=3.4.23-0+deb10u1
3.4.23-0+deb10u2
3.5.24-0+deb11u1
3.7.10-0+deb12u1
3.9.0-2

Remedy

Patched versions of Postfix before 3.9 require the below configs for the fix to apply: smtpd_forbid_bare_newline = normalize smtpd_forbid_bare_newline_exclusions = $mynetworks

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Reference Links

Parent vulnerabilities

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