6

The process would be that the browser send a request to MITMproxy and then generate a request that gets sent to target proxy server which isn't controlled by us. The proxy server would send a response to MITMproxy which would then relay that response to the browser.

How would I go about doing this?

Jonathan
  • 8,453
  • 9
  • 51
  • 74

4 Answers4

15

I was able to achieve what you ask with the following. You need to enable the upstream mode and upstream auth (in case you have some username/password for your proxy):

mitmproxy --mode upstream:https://HOSTNAME:PORT --upstream-auth USER:PASSWORD

Then you can check it's working with a simple curl:

curl -x http://localhost:8080 -k https://api.ipify.org/

This will forward your request to mitmproxy which will forward it to your other proxy.

Hope it helps!

jpbalarini
  • 1,082
  • 1
  • 17
  • 23
  • 1
    FYI for others, most of the other answers seem to be for very old versions of mitmproxy. For anything recent (v3+), this `--mode upstream:` option is the way it's done. See https://docs.mitmproxy.org/stable/concepts-options/ – chucknelson Feb 27 '21 at 15:00
5

You can do this with the -F flag to mitmproxy, which forwards proxy requests to an upstream server. Take a look at the docs here:

http://mitmproxy.org/doc/features/forwardproxy.html

cortesi
  • 96
  • 1
1

If you'd like to do this not from the script, you can change the upstream server with get_upstream_server from server.config see [mitmproxy config] (https://github.com/mitmproxy/mitmproxy/blob/42d4a2fae96b8b4ba35d3a88e20f278d79a0ccc6/libmproxy/proxy.py). For example:

self.server.config.get_upstream_server = proxy.ConstUpstreamServerResolver(cmdline.parser_server_spec("http://upstreamserver:port"))
user2573072
  • 81
  • 4
0

I think it's the -U option:

command-line    -U http://hostname[:port]

source: http://docs.mitmproxy.org/en/stable/features/upstreamproxy.html

ospider
  • 9,334
  • 3
  • 46
  • 46