source: https://www.securityfocus.com/bid/9388/info
It has been reported that FreeWeb server of FreeProxy may be prone to a directory traversal vulnerability that may allow a remote attacker to access information outside the server root directory. The issue may allow a remote attacker to traverse outside the server root directory by using '../' character sequences.
FreeProxy versions 3.6 and prior are reported to be prone to this issue.
http://www.example.com/../../../../boot.ini%00.html