The check_logout function in class/auth.php in Help Center Live (hcl) 2.1.3a sends a redirect to the web browser but does not exit when administrative credentials are missing, which allows remote attackers to delete administrative users and have other unspecified impact via certain requests to (1) admin/departments.php, (2) admin/operators.php, and other unspecified scripts.  NOTE: some of these details are obtained from third party information.