(RHSA-2003:028) pam security update

The pam_xauth module is used to forward xauth information from user to user
in applications such as the su command.

Andreas Beck discovered that pam_xauth will forward authorization
information from the root account to unprivileged users. This could be
used by a local attacker to gain access to an administrator’s X session.
To exploit this vulnerability the attacker would have to get the
administrator, as root, to use su to access the account belonging to the
attacker.

Users of pam_xauth are advised to upgrade to these errata packages which
contain a patch which adds ACL (access control list) functionality to
pam_xauth and disallows root forwarding by default.

Thanks to Andreas Beck for reporting this issue.