pymiproxy - Python Micro Interceptor Proxy
A small and sweet man-in-the-middle proxy capable of doing HTTP and HTTP over SSL.
pymiproxy is a small, lightweight, man-in-the-middle proxy capable of performing HTTP and HTTPS (or SSL) inspection. The proxy provides a built-in certificate authority that is capable of generating certificates for SSL-based destinations. Pymiproxy is also extensible and provides two methods for extending the proxy: method overloading, and a pluggable interface. It is ideal for situations where you're in dire need of a cool proxy to tamper with out- and/or in-bound HTTP data.
The following modules are required:
Just run the following command at the command prompt:
$ sudo python setup.py install
The module offers a few examples in the code. In brief, pymiproxy can be run right-away by issuing the following command at the the command-prompt:
$ python -m miproxy.proxy
This will invoke pymiproxy with the
DebugInterceptor plugin which simply outputs the first 100 bytes of each request
and response. The proxy runs on port 8080 and listens on all addresses. Go ahead and give it a try.
Extending or Implementing pymiproxy
There are two ways of extending the proxy:
- Develop and register an Interceptor plugin; or
- Overload the
mitm_responsemethods in the
The decision on which method you choose to use is entirely dependant on whether or not you wish to push the data being intercepted through a set of interceptors or not.
There are currently two types of interceptor plugins:
RequestInterceptorPlugins: executed prior to sending the request to the remote server; and
ResponseInterceptorPlugins: executed prior to sending the response back to the client.
The following flow is taken by pymiproxy in this mode:
- Client request received
- Client request parsed
- Client request processed/transformed by Request Interceptor plugins
- Updated request sent to remote server
- Response received by remote server
- Response processed/transformed by Response Interceptor plugins
- Updated response sent to client
You can register as many plugins as you wish. However, keep in mind that plugins are executed in the order that they are registered in. Take care in how you register your plugins if the result of one plugin is dependent on the result of another.
The following is a simple code example of how to run the proxy with plugins:
from sys import argv from miproxy.proxy import RequestInterceptorPlugin, ResponseInterceptorPlugin, AsyncMitmProxy class DebugInterceptor(RequestInterceptorPlugin, ResponseInterceptorPlugin): def do_request(self, data): print '>> %s' % repr(data[:100]) return data def do_response(self, data): print '<< %s' % repr(data[:100]) return data if __name__ == '__main__': proxy = None if not argv[1:]: proxy = AsyncMitmProxy() else: proxy = AsyncMitmProxy(ca_file=argv) proxy.register_interceptor(DebugInterceptor) try: proxy.serve_forever() except KeyboardInterrupt: proxy.server_close()
The alternate approach to extending the proxy functionality is to subclass the ProxyHandler class and overload the
mitm_response methods. The following is a quick example:
from sys import argv from miproxy.proxy import AsyncMitmProxy, ProxyHandler class MitmProxyHandler(ProxyHandler): def mitm_request(self, data): print '>> %s' % repr(data[:100]) return data def mitm_response(self, data): print '<< %s' % repr(data[:100]) return data if __name__ == '__main__': proxy = None if not argv[1:]: proxy = AsyncMitmProxy(RequestHandlerClass=MitmProxyHandler) else: proxy = AsyncMitmProxy(RequestHandlerClass=MitmProxyHandler, ca_file=argv) try: proxy.serve_forever() except KeyboardInterrupt: proxy.server_close()
Note: In both cases, the methods that process the data need to return the data back to the proxy handler. Otherwise, you'll get an exception.
Thanks to the great documentation at python.org, GnuCitizen's PDP for the ideas, the pyOpenSSL group for making a great OpenSSL API.