BackOrifice

Back Orifice (often shortened to BO) is a controversial computer program designed for remote system administration. It enables a user to control a computer running the Microsoft Windows operating system from a remote location.

Although Back Orifice has legitimate purposes, such as remote administration, there are other factors that make it suited for less benign business. The server can hide itself from cursory looks by users of the system. As the server can be installed without user interaction, it can be distributed as payload of a Trojan horse.

For those and other reasons, the antivirus industry immediately categorized the tool as malware and appended Back Orifice to their quarantine lists. Despite this fact, it was widely used by script kiddies because of its simple GUI and ease of installation.