The screensaver on Windows NT 4.0, 2000, XP, and 2002 does not verify if a domain account has already been locked when a valid password is provided, which makes it easier for users with physical access to conduct brute force password guessing.
NT Virtual DOS Machine (NTVDM.EXE) in Windows 2000, NT and XP does not verify user execution permissions for 16-bit executable files, which allows local users to bypass the loader and execute arbitrary programs.
Windows NT 4.0 SP 6a allows a local user with write access to winnt/system32 to cause a denial of service (crash in lsass.exe) by running the NT4ALL exploit program in 'SPECIAL' mode.
Windows 2000 and Windows NT allows local users to cause a denial of service (reboot) by executing a command at the command prompt and pressing the F7 and enter keys several times while the command is executing, possibly related to an exception handling error in csrss.exe.