(RHSA-2007:0465) Moderate: pam security and bug fix update

Pluggable Authentication Modules (PAM) provide a system whereby
administrators can set up authentication policies without having to
recompile programs that handle authentication.

A flaw was found in the way the Linux kernel handled certain SG_IO
commands. Console users with access to certain device files had the ability
to damage recordable CD drives. The way pam_console handled permissions of
these files has been modified to disallow access. This change also required
modifications to the cdrecord application. (CVE-2004-0813)

A flaw was found in the way pam_console set console device permissions. It
was possible for various console devices to retain ownership of the console
user after logging out, possibly leaking information to an unauthorized
user. (CVE-2007-1716)

The pam_unix module provides authentication against standard /etc/passwd
and /etc/shadow files. The pam_stack module provides support for stacking
PAM configuration files. Both of these modules contained small memory leaks
which caused problems in applications calling PAM authentication repeatedly
in the same process.

All users of PAM should upgrade to these updated packages, which resolve
these issues.