The default setting for the Winlogon key entry ShutdownWithoutLogon in Windows NT allows users with physical access to shut down a Windows NT system without logging in.
Windows NT 3.51 and 4.0 running WINS (Windows Internet Name Service) allows remote attackers to cause a denial of service (resource exhaustion) via a flood of malformed packets, which causes the server to slow down and fill the event logs with error messages.