BDFProxy allows you to patch binaries via MiTM with The Backdoor Factory combined with mitmproxy enabling on the fly patching of binary downloads (software updates for example) from vendors that don’t validate data integrity.
The Backdoor Factory allows you to patch binaries with shell-code so combining that with mitmproxy, which is a Python proxy-server that can catch HTTP, change traffic on the fly, replay traffic, decode and render primitive data types – gives you BDFProxy.