Back Orifice is a remote administration system which allows a user to control a computer across a tcpip connection using a simple console or GUI application. On a local LAN or across the internet, BO gives its user more control of the remote Windows machine than the person at the keyboard of the remote machine has.
Remember the havoc this trojan caused?
BackOrifice on a machine with a webcam.
Read the NETBEUI message and see the pic below it
* formation of this page inspired by this /. article