/* Identifies the modification of RDP Shadow registry or
  the execution of processes indicative of active shadow RDP session */

any where host.os.type == "windows" and
(
  (event.category == "registry" and
     registry.path : (
      "HKLM\\Software\\Policies\\Microsoft\\Windows NT\\Terminal Services\\Shadow",
      "\\REGISTRY\\MACHINE\\Software\\Policies\\Microsoft\\Windows NT\\Terminal Services\\Shadow",
      "MACHINE\\Software\\Policies\\Microsoft\\Windows NT\\Terminal Services\\Shadow"
    )
  ) or
  (event.category == "process" and event.type == "start" and
     (process.name : ("RdpSaUacHelper.exe", "RdpSaProxy.exe") and process.parent.name : "svchost.exe") or
     (?process.pe.original_file_name : "mstsc.exe" and process.args : "/shadow:*")
  )
)