Possible DCSync/DCShadow Attack from Non-Domain Controller
This rule detects remote RPC calls to the Microsoft Directory Replication Service Remote Protocol (MS-DRSR) originating from hosts that are not designated as Domain Controllers. Such activity is highly indicative of potential DCSync or DCShadow attacks, where an attacker attempts to replicate Active Directory data, including sensitive credentials, by impersonating a Domain Controller. The rule specifically looks for RPC Firewall logs (EventLog: RPCFW, EventID: 3) where the InterfaceUuid matches 'e3514235-4b06-11d1-ab04-00c04fc2dcd2' (MS-DRSR) and the operation number (OpNum) is not 0, 1, or 12, as these are considered 'dangerous' opcodes when initiated from non-DC hosts.
Sigma
