There are several kinds of computer malware programs that can damage your computer, including spyware, worms, viruses and Trojans. According to anti-virus software maker McAfee, a Trojan is not a virus because it does not replicate itself when it infects a machine. A Trojan slips into a computer pretending to be a non-threatening program, and then begins to attack the various administrative functions of your operating system and programs. New Trojans are being developed constantly, and the list of Trojan program names keeps growing.
The backdoor Trojan program is one that attacks the computer through an open Internet port. The Clampi.a Trojan slips in through an unprotected Internet port and is initiated when the computer is rebooted. The Trojan connects to a web server and begins to transmit the user's personal data to a receiver at the server.
This Trojan contains a series of programs that will begin running on the infected computer without the user's consent. These programs can include data mining procedures that transmit the user's personal information to a receiver server, adware that creates pop-up ads, and redirects that will send the user to websites to which he did not intend to go.
The FakeAV Trojan is a system tray program that embeds itself in the Windows system tray and then continually pops up requesting that the user click on a link to register for virus protection software. If the link is clicked then more malware is loaded on to the user computer from a remote web server.