Amazon Linux 1 Security Advisory: ALAS-2024-1914
Advisory Release Date: 2024-02-01 19:33 Pacific
Advisory Updated Date: 2024-02-01 19:33 Pacific
Postfix through 3.8.4 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: 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. (CVE-2023-51764)
Affected Packages:
postfix
Issue Correction:
Run yum update postfix to update your system.
i686:
postfix-debuginfo-2.6.6-2.17.amzn1.i686
postfix-2.6.6-2.17.amzn1.i686
postfix-perl-scripts-2.6.6-2.17.amzn1.i686
src:
postfix-2.6.6-2.17.amzn1.src
x86_64:
postfix-2.6.6-2.17.amzn1.x86_64
postfix-debuginfo-2.6.6-2.17.amzn1.x86_64
postfix-perl-scripts-2.6.6-2.17.amzn1.x86_64