Today I am going to cover tunneling through Squid HTTP Proxy as I have gotten many questions about it!
Here is the services on my host also known as my VM (Pinky's-Palace-Intermediate)
If we try and request the Nginx server we get a 403, most likely because nobody from outside the host is allowed to access resources on this server.
But if we look back at our scan we have a port open with a Squid HTTP proxy server being hosted. We can use this proxy server when configured incorrectly to pivot to the internal host! As this Nginx server is serving content on localhost as well.
So lets setup our browser to tunnel our traffic through the Squid proxy so we can access the web server on localhost.
Here I am using an extension for firefox called FoxyProxy. I am configuring an option to route my HTTP traffic to the Squid proxy server on my VM. Once you have done that click on the extension icon and enable the configuration you created. Now your traffic will be tunneling through the Squid proxy!
Now I route to http://127.0.0.1:8080 and it routes my traffic through the proxy and right to the server hosted on localhost (127.0.0.1).