source: http://www.securityfocus.com/bid/11562/info

Global Spy Software Cyber Web Filter is affected by an IP filter bypass vulnerability. This issue is due to a failure of the application to properly handle exceptional HTTP requests.

An attacker may leverage this issue to bypass filters based on IP addresses, allowing an attacker to visit restricted Web sites.

To access the hypothetical IP address 100.100.100.100, the following requests would be used:

http://100.0100.100.100
http://00000144.00000144.00000144.00000144