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Using mitmproxy with an Android phone

This is how I got a Nexus 5, running Android L, to route HTTP and HTTPS requests through mitmproxy:

Connected the phone to my Mac with a USB cable, which caused an Android File Transfer window to appear, as I have the developer tools installed.

Copied ~/.mitmproxy/mitmproxy-ca-cert.cer to my phone by dragging it to the Android File Transfer window.

On my phone, went to Settings → Security → Install from storage (under Credential storage), navigated to the location where I dropped the file, and selected it.

In the dialog that appeared, I entered mitmproxy as name and pressed ok. A warning triangle now appeared in the top left corner ("Network may be monitored").

Went to Settings → Wi-Fi and long-pressed on my network name, and selected Modify network in the panel that appeared.

Selected Advanced options, changed proxy from None to Manual, and then keyed in the IP address on my Mac with mitmproxy running, and port `8080.

Started mitmproxy on my Mac (see previous post).

Now HTTP and HTTPS requests from my phone started showing up:

[ehnmark-devblog]

Using mitmproxy on a Mac

As the few mitmproxy tutorials I've seen so far have been a bit cryptic, and assumed a fair amount of background knowledge, I decided to write down how I got it to work on Mac OS X Yosemite.

First, I used Homebrew to download and install mitmproxy:

> brew install mitmproxy

Once installed, I simply ran it:

> mitmproxy

Now I had a proxy running, but nothing actually using it. To route HTTP(S) requests to it, I opened the Network system preferences pane, selected my active network interface (which happened to be wifi), pressed the Advanced… button, and then the Proxies tab.

Here, I enabled Web Proxy and Secure Web Proxy, and in both cases keyed in 127.0.0.1 as host and 8080 as port.

After saving and then pressing Apply in the Network panel, I started seeing requests in mitmproxy:

The last step required to see HTTPS traffic is to install the certificate authority, which is as simple as this:

> open ~/.mitmproxy/mitmproxy-ca-cert.pem

Bonus: Toggling proxy on and off

To avoid having to manually toggle proxies on and off when I want to use mitmproxy, I went back to the Network preference panel, opened the Location popup, duplicated my current configuration. I then changed the new clone to not use proxies.

Now I can quickly toggle between proxy and no-proxy configurations from the Apple menu: