source: http://www.securityfocus.com/bid/2801/info

eSafe Gateway is a security utility used for filtering internet content.

An html file may be crafted to bypass the script-filtering feature offered by eSafe Gateway. This is done by simply encoding the <SCRIPT> tag in Unicode format, such that the filter ignores the call to execute the script. 

http://www.exploit-db.com/sploits/20891.zip