I made a small PoC. cs-mitm. py is a mitmproxy script that intercepts Cobalt Strike traffic, decrypts it and injects its own commands. In this video, a malicious beacon is terminated by sending it an exit command. I selected a malicious beacon that uses one of the leaked private keys.

The script does not support data transforms, but that can be easily added, for example with code found in cs-parse-traffic.py.