Subseven, also known as Sub7, is a remote control program for PC computers. It is considered a trojan horse program as it is installed as an invisible application. While it can be used for legitimate remote control, it is commonly used by hackers to take over computers. It was developed by Mobman, and has been around for about three years. A Macintosh client has been developed, and a Macintosh server is in the works.

Subseven has many features, including: A keylogger, the ability to retrieve information about the computer, user information, and passwords, a chat feature, an FTP server, the ability to bring up webpages on the target computer, the ability to flip the screen on the target computer, and the ability to monitor the target computer's screen or webcam. Additional features include shutting down Windows, controlling the mouse, opening the CD ROM, and turning the monitor on or off. Subseven has become the most popular trojan horse virus, bypassing both Back Orifice and Netbus in terms of computers infected. The common port that Subseven operates on is 27374. It has also been found running on port 1243.