Ultimate PHP Board (UPB) 1.0b stores the users.dat data file under the web root with insufficient access control, which allows remote attackers to obtain usernames and passwords.
http://www.securityfocus.com/bid/5858
http://www.iss.net/security_center/static/10300.php
http://archives.neohapsis.com/archives/bugtraq/2002-10/0016.html