Lotus Domino server 5.0.8 with NoBanner enabled allows remote attackers to (1) determine the physical path of the server via a request for a nonexistent file with a .pl (Perl) extension, which leaks the pathname in the error message, or (2) make any request that causes an HTTP 500 error, which leaks the server's version name in the HTTP error message.
http://www.securityfocus.com/bid/4049
http://www.iss.net/security_center/static/8160.php
http://www-1.ibm.com/support/manager.wss?rs=1&rt=0&org=sims&doc=07B32060E4CC97E985256B64005AEB0F