source: http://www.securityfocus.com/bid/24855/info

TippingPoint IPS is prone to a detection-bypass vulnerability because the appliance fails to properly handle Unicode characters.

A successful exploit of this issue may allow an attacker to bypass the filter and detection system of vulnerable appliances, allowing malicious URI traffic through. This will likely aid the attacker in further attacks.

http://www.example.com/scripts%c0%afcmd.exe
http://www.example.com/scripts%e0%80%afcmd.exe
http://www.example.com/scripts%c1%9ccmd.exe