How to create Man in the Middle instrumentation
fiddler, openssl, sockets, ssl
Solution
Fiddler allows you to implement a man in the middle attack against yourself to see what is inside the SSL tunnel.
Fiddler generates a unique root SSL certificate for your computer, and then creates a session certificate signed by the root. When you configure Fiddler to decrypt SSL for you it acts as a proxy between you and the destination, decrypting the traffic using the site's SSL certificate and then re-encrypting it using its own certificate.
Your browser/application will see an untrusted certificate error. You can get around this error by choosing to trust Fiddler's root certificate.
The folks over at .Net Rocks did a great podcast episode on using Fiddler to sniff your traffic.
Problem
I'm trying to see how a certain application is talking to a server in SSL. Basically, the process just hangs when it claims to have done some SSL communication. I want to debug the problem by catching the traffic, but I can't really use a sniffer since SSL will probably look like a hexdump. Is there a good man-in-the-middle tool that I could use as instrumentation? I just need something that will show me the decrypted communication. Hopefully very easy to setup. I could even point the application to any IP address/port available to my machine (eg localhost:8888), so proxies would be fine. Also, I can probably configure the application to accept any certificate. What do you use to simulate a man-in-the-middle (mitm) SSL attack? UPDATE: I tried fiddler and can't get it to work. I installed openssl and typed the following command: `openssl s_client -connect smtp.gmail.com:465` Gmail responds with their certificate and a `220 mx.google.com ESMTP ...`. However, Fiddler does not capture the traffic. I set the WinINET options in fiddler to "Use the same proxy server for all protocols". Can anyone else get this to work (or not work)? I think I need to find a way to have openssl use a proxy.