Cracking wmiexec in Rust by byte-diffing against impacket

Most people treat impacket as a library. I treat it as a debugging oracle — a black box that emits the exact bytes a Windows DC will accept, and my job is to reproduce those bytes byte-for-byte in Rust. That's how I got wmiexec working from scratch inside ADhammer, an Active Directory audit toolkit built on my own DCE/RPC · NTLM · SMB2 · Kerberos stack (think "impacket for Rust").

The whole project is built with Claude Code, and this was the tightest loop I've ever had with an AI. Not autocomplete — a real hypothesis → capture traffic → diff → fix cycle against a live domain controller, with Claude reading the diffs alongside me.

What wmiexec actually does

wmiexec is the classic "quiet" RCE path. Instead of creating a service (psexec/SVCCTL) or a scheduled task (atexec), you talk to WMI over DCOM and call Win32_Process.Create. No service-install event, different host telemetry. Under the hood it's three stages, each a different flavor of pain:

1. DCOM activation — you send a RemoteCreateInstance to the WMI DCOM server and get back an object reference.
2. OXID resolution — the DC returns an OXID string, and you have to call the OXID resolver to turn it into a binding. This is where most of the "garbage error" happens.
3. MS-WMIO object marshaling — you invoke the WMI service and class methods with correct NDR marshalling for