source: http://www.securityfocus.com/bid/4646/info

BEA Systems WebLogic Server is an enterprise level web and wireless application server for Microsoft Windows and most Unix and Linux distributions.

BEA WebLogic Express provides a platform for serving dynamic data to web and wireless applications.

It is possible to create a denial of service condition by appending a null character to a request for a MS-DOS device name (such as AUX). Multiple malformed requests will cause the server to hang.

BugTraq ID 3816 "BEA Systems WebLogic Server DOS Device Denial of Service Vulnerability" describes a similar condition, which was fixed in WebLogic Server 6.1 SP2. However, the null character variation of this attack affects systems running WebLogic Server 6.1 SP2.

The server must be restarted to regain normal functionality. 

This issue may be exploited with a web browser. For example:

http://target//aux%00