#USING MITMPROXY INSTALL#

Install Mitmproxy’s CA by visiting, clicking on “other” and selecting “trust this CA to identify web sites”.

At this stage, this is expected behavior, because Mitmproxy has on the fly generated a fake certificate, signed by Mitmproxy’s built in mini-CA, which of course is unknown to your browser, at this stage. This should result in a certificate error - if it doesn’t, the certificate checking logic of your browser is broken.

Try visiting an HTTPS website in your browser.

192.168.127.44 happened to be the IP address of the Mitmproxy machine in my home network at the time of testing. In my first test this was Firefox, and it could well have been on a different computer, as long as it can talk TCP on port 8080 to the Mitmproxy machine.

Configure your browser to use 192.168.127.44:8080 as a proxy for all protocols.

This is an interactive program (character based, curses-like user interface), initially showing one line per flow (HTTP request-response pair). mitmdump -help shows a long list of options, I won’t repeat here. If you would like some other port than 8080, you can change it by a command line option.

Open the desktop’s firewall to permit inbound traffic on TCP port 8080, which is the default port mitmproxy listens on.

home/martin/bin by tar xvzf mitmproxy-1.0. results in three binaries: mitmdump, mitmproxy and mitmweb.

#USING MITMPROXY PC#

I did it on a desktop PC running Ubuntu Mate 16.04 LTS, 64-bit. Mitmproxy is at home on Linux, but there is also a Windows version available. Attempting it on a 32-bit system fails with odd error messages you won’t at first glance relate to 64-vs-32-bit issues.

You absolutely need a 64-bit OS to run Mitmproxy on. The name is a combination of the acronym Man In The Middle (the type of attack performed here) and proxy, a type of server widely use especially in company’s internal networks. It is a suite consisting of the interactive program Mitmproxy and the stream dumper (think tcpdump) mitmdump. This includes intercepting SSL traffic, which in theory should be hard, but in practice is easy, by using Mitmproxy as a web proxy. I have set up an environment to check what really happens. I have heard of too many stories of browser add-ons reporting innocent user’s browsing history to data vendors, disguised as “anonymous usage statistics”, which later turns out to be not very anonymous, but easily traceable to individuals.

Using mitmproxy