EntropyCapture is a standalone DLL that, when injected into a process that is using optional entropy, will perform the API hooking, capture the entropy, and write the value to a file. Converting the DLL into shellcode using the sRDI project allows the included aggressor script to monitor and inject into the provided process name. When started, EntropyCapture will retrieve a process list, search for the provided application name, and then inject into it.
When the aggressor script is loaded into Cobalt Strike, the following new commands are available:
- start_entropyCapture [process name] – Starts checking for the stated process and injects into them.
- stop_entropyCapture – Stops checking but will not unload the already loaded DLL.
- show_entropyCapture – Prints the contents of the file showing the captured entropy.