how do you detect CGIproxy ?

Question

i have cgiproxy (http://www.jmarshall.com/tools/cgiproxy/), which lets users use it to navigate pages.

it seems like myspace.com detects it and forwards the user to google.com

doing a quick test to determine my ip using the proxy fails, meaning it doesn't reveal my ip. it shows proxy server's ip.

<?php

if (getenv("HTTP_X_FORWARDED_FOR")) {
      $ip   = getenv("HTTP_X_FORWARDED_FOR");
    } else {
      $ip   = getenv("REMOTE_ADDR");
}
print"$ip";

So the mystery is, how are sites out there detecting that i am using CGI proxy ? is it possible for cgi proxy to stay undetected?

btw CGI proxy is best because it renders JS.

Answer 1

Perhaps in your PHP test program, you could dump out all the HTTP headers to see what's coming through and whether there is anything that looks like identifying information. It's hard for us to guess what Myspace is doing.

Answer 2

Totally a guess, but you may not be getting the MySpace cookies through CGIProxy.

CGIProxy states it as a known limitation:

If you browse to many sites with cookies, CGIProxy may drop some. If a site keeps telling you to enable cookies, delete your existing cookies (via the "Manage cookies" link) and try the site again.

One other option (assuming you have shell access to the machine running the proxy) is to use the SOCKS proxy included in SSH with the -D flag.

Answer 3

I believe what you would want to install is PHProxy:
http://sourceforge.net/projects/poxy/

Back in HS days this is what we used to get around the filters that the school put in place to block it. Worked fairly well as far as I remember it, I haven't tried it recently but it is worth a shot.

Answer 4

Some sites, like MySpace, don't want users connecting through a proxy, so they go to lengths to detect this. By default, CGIProxy, does add any header to make it detectable. An easy way to check your http headers is to visit http://www.ioerror.us/ip/headers .

The usual method to detect this sort of thing is for a bit of client side Javascript to inspect the URL of the page it's on, and send that to the server. Using nph-proxy.cgi I'm able to visit Myspace without any such redirections.

Other methods are for detection include embedding a Flash or Java object on the page, and having that object attempt to connect to a hard coded server.