Secunia

Description

Red Hat has issued an update for postfix. This fixes a security issue, which can be exploited by malicious people to use a vulnerable system as an open relay.

The problem is caused due to an error in the IPv6 handling when "/proc/net/if_inet6" is not available (e.g. when running in a chroot jail). This makes it possible to relay mails through the system to any MX host with an IPv6 address.

Successful exploitation requires that "permit_mx_backup" is enabled in "smtpd_recipient_restrictions".

Solution
Updated packages are available from Red Hat Network.
Further details available in Customer Area

Original Advisory
http://rhn.redhat.com/errata/RHSA-2005-152.html

Deep Links
Links available in Customer Area