NT Versions Affected:

3.5?, 3.51?, 4.0

Problem:

Executables renamed as .xxx files run as executable from command line. Executables can be renamed with any extension and run from the command prompt or batch file. Subverts filtering/download control by filename extension.

Also executables without a filename extension can be started from the command prompt or batch file, as NT will try to run the file as .COM, .EXE, or .BAT in that order.

Potential trojan.

Verification:

Copy notepad.exe to notepad.doc, open command window, type 'start notepad.doc'.