ALAS-2024-2420

Amazon Linux 2 Security Advisory: ALAS-2024-2420
Advisory Release Date: 2024-01-19 01:51 Pacific
Advisory Updated Date: 2024-01-22 20:21 Pacific
Severity: Important
Issue Overview:

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


Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.


Issue Correction:
Run yum update postfix to update your system.

New Packages:
aarch64:
    postfix-2.10.1-6.amzn2.0.4.aarch64
    postfix-perl-scripts-2.10.1-6.amzn2.0.4.aarch64
    postfix-debuginfo-2.10.1-6.amzn2.0.4.aarch64

i686:
    postfix-2.10.1-6.amzn2.0.4.i686
    postfix-perl-scripts-2.10.1-6.amzn2.0.4.i686
    postfix-debuginfo-2.10.1-6.amzn2.0.4.i686

noarch:
    postfix-sysvinit-2.10.1-6.amzn2.0.4.noarch

src:
    postfix-2.10.1-6.amzn2.0.4.src

x86_64:
    postfix-2.10.1-6.amzn2.0.4.x86_64
    postfix-perl-scripts-2.10.1-6.amzn2.0.4.x86_64
    postfix-debuginfo-2.10.1-6.amzn2.0.4.x86_64

Additional References

Red Hat: CVE-2023-51764

Mitre: CVE-2023-51764