Slackware 15.0: 2023-356-01 moderate: Postfix email spoofing threat

Here are the details from the Slackware 15.0 ChangeLog: patches/packages/postfix-3.6.13-i586-1_slack15.0.txz: Upgraded. Security: this release adds support to defend against an email spoofing attack (SMTP smuggling) on recipients at a Postfix server. Sites concerned about SMTP smuggling attacks should enable this feature on Internet-facing Postfix servers. For compatibility with non-standard clients, Postfix by default excludes clients in mynetworks from this countermeasure. The recommended settings are: # Optionally disconnect remote SMTP clients that send bare newlines, # but allow local clients with non-standard SMTP implementations # such as netcat, fax machines, or load balancer health checks. # smtpd_forbid_bare_newline = yes smtpd_forbid_bare_newline_exclusions = $mynetworks The smtpd_forbid_bare_newline feature is disabled by default. For more information, see: https://www.postfix.org/smtp-smuggling.html (* Security fix *)