PortSwigger / python-scripter

Sourced from gist: https://gist.github.com/mwielgoszewski/7026954
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Python Scripter

Current parent repository

Introduction

This extension allows you to write custom Python to hook into both the request, response pipeline and also the Macro handling support in Burp Suite. This is useful in those times were you want some behaviour but don't want to have to go to the full extent of creating a custom extension.

You can also over time build up a useful collection of utility scripts that can be used across web assessments.

I would highly recommend to build off the already established framework pyscripter-er that already has a lot of common functionality built-in to save you some of the leg work.

Usage

Once the extension is installed you will find a Python Scripts tab, this allows you to add, modify or remove scripts:

Python Scripts with no scripts

When you add a new script it will be given a name of New Script X this can be changed in the same way as in the Repeater tabs by double clicking and pressing Enter to confirm or Esc to cancel.

You can then start changing the new script or pasting a script from another location directly into the editor:

Renaming the script via the tab

When your ready to compile the Python code simply click Compile, compile time errors these will be displayed in the Errors textarea:

Compile time errors

To test the script simply enable it and then push through a request, output should be presented in the Output textarea:

Script output

If there was a runtime exception these will also be captured in the Errors textarea to help diagnose the bug.

Scripts are automatically restored and saved on extension load and unload.

State Dictionary

There are scenarios when values retrieved from previous requests or responses are required for the next request, this can sometimes be performed using Macros however if this behaviour is used for every endpoint this becomes unworkable as a solution. That is why the state dictionary was introduced so that it is possible to persist values that can be later retrieved in a subsequent request/response.

An example of this could be an application that returns a unique token in the response and this must be provided into the next request, this could be handled using the following:

if messageIsRequest:
    if 'x-req' in state: # see if we have a token from prev resp
        req = helpers.analyzeRequest(messageInfo)
        headers = req.headers
        headers.add('X-Request: {}'.format(state['x-req']))  # put the token into the req
        body = messageInfo.request[req.bodyOffset:]
        new_req = helpers.buildHttpMessage(headers, body)
        messageInfo.request = new_req  # replace the current req with the updated version
        print('Added X-Request header: {}'.format(state['x-req']))
else:
    token = ... # perform retrieval of token (e.g. hidden form field, meta tag etc...); Macro regex generator could help with this ;)
    state['x-req'] = token  # save in state to be used in next req
    print('Saved X-Request from response: {}'.format(token))

FAQs

Q. Why do I see no output?

A. As long as the script is enabled this could be that there was a runtime exception raised, firstly check the Errors textarea, could be that the scope checking in place is incorrect if your using callbacks.isInScope perhaps placing a print before and after this is comparesd coud help track down the issue. It may also be the case that the extension has an exception in which case you should check the Errors textare from the extensions dialog in Burp Suite.

Original Work

Sourced from gist: https://gist.github.com/mwielgoszewski/7026954