mitmproxy

mitmproxy is a console tool that allows interactive examination and modification of HTTP traffic. It differs from mitmdump in that all flows are kept in memory, which means that it’s intended for taking and manipulating small-ish samples. Use the ? shortcut key to view, context-sensitive documentation from any mitmproxy screen.

Flow list

The flow list shows an index of captured flows in chronological order.

• 1: A GET request, returning a 302 Redirect response.
• 2: A GET request, returning 16.75kb of text/html data.
• 3: A replayed request.
• 4: Intercepted flows are indicated with orange text. The user may edit these flows, and then accept them (using the a key) to continue. In this case, the request has been intercepted on the way to the server.
• 5: A response intercepted from the server on the way to the client.
• 6: The event log can be toggled on and off using the e shortcut key. This pane shows events and errors that may not result in a flow that shows up in the flow pane.
• 7: Flow count.
• 8: Various information on mitmproxy’s state. In this case, we have an interception pattern set to .*.
• 9: Bind address indicator - mitmproxy is listening on port 8080 of all interfaces.

Flow view

The Flow View lets you inspect and manipulate a single flow:

• 1: Flow summary.
• 2: The Request/Response tabs, showing you which part of the flow you are currently viewing. In the example above, we’re viewing the Response. Hit tab to switch between the Response and the Request.
• 3: Headers.
• 4: Body.
• 5: View Mode indicator. In this case, we’re viewing the body in hex mode. The other available modes are pretty, which uses a number of heuristics to show you a friendly view of various content types, and raw, which shows you exactly what’s there without any changes. You can change modes using the m key.

Grid Editor

Much of the data that we’d like to interact with in mitmproxy is structured. For instance, headers, queries and form data can all be thought of as a list of key/value pairs. Mitmproxy has a built-in editor that lays this type of data out in a grid for easy manipulation.

At the moment, the Grid Editor is used in four parts of mitmproxy:

• Editing request or response headers (e for edit, then h for headers in flow view)
• Editing a query string (e for edit, then q for query in flow view)
• Editing a URL-encoded form (e for edit, then f for form in flow view)
• Editing replacement patterns (o for options, then R for Replacement Patterns)

If there is is no data, an empty editor will be started to let you add some. Here is the editor showing the headers from a request:

To edit, navigate to the key or value you want to modify using the arrow or vi navigation keys, and press enter. The background color will change to show that you are in edit mode for the specified field:

Modify the field as desired, then press escape to exit edit mode when you’re done. You can also add a row (a key), delete a row (d key), spawn an external editor on a field (e key). Be sure to consult the context-sensitive help (? key) for more.

Example: Interception

mitmproxy‘s interception functionality lets you pause an HTTP request or response, inspect and modify it, and then accept it to send it on to the server or client.

1: Set an interception pattern

We press i to set an interception pattern. In this case, the ~q filter pattern tells mitmproxy to intercept all requests. For complete filter syntax, see the Filter expressions section of the documentation, or the built-in help function in mitmproxy.

2: Intercepted connections are indicated with orange text:

3: You can now view and modify the request:

In this case, we viewed the request by selecting it, pressed e for “edit” and m for “method” to change the HTTP request method.

4: Accept the intercept to continue:

Finally, we press a to accept the modified request, which is then sent on to the server. In this case, we changed the request from an HTTP GET to OPTIONS, and Google’s server has responded with a 405 “Method not allowed”.