A C# tool to gather the administrators on the domain controller (including local accounts) and detects when it changes.
Whenever a new domain admin is added, it is notified on the console of this tool
The same thing can be monitored from Windows Event Logs with event ID 4728 and check for any attempts of addding users into a Administrators groups of a domain controller.
Blogpost Link - https://rootdse.org/posts/monitoring-realtime-activedirectory-domain-scenarios