I found 6 private keys used by malicious Cobalt Strike servers. There’s a significant number of malicious CS servers on the Internet that reuse these keys, thus allowing us to decrypt their C2 traffic. For the details, I recommend reading the following blog post I wrote “Cobalt Strike: Using Known Private Keys To Decrypt Traffic – Part 1“.

I integrated these keys in the database (1768.json) of my tool 1768.py (starting version 0.0.8).

Whenever you analyze a beacon with 1768.py that uses a public key with a known private key, the report will point this out:

And when you use option verbose, the private key will be included:

If you want to integrated these 6 keys in your own tools: be my guest. You can find these key pairs in 1768.json.