The pam_xauth module is used to forward xauth information from user to user
in applications such as 'su'.
Andreas Beck discovered that versions of pam_xauth supplied with Red Hat
Linux since version 7.1 would 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. In order to exploit this
vulnerability, the attacker would have to get the administrator, as root,
to use su to the account belonging to the attacker.
