A trojan horse is a program appearing to be something safe, but is performing malicious tasks, such as giving access to your computer or sending personal information to other computers. Trojan horses are one of the most common methods a computer criminal uses to infect your computer and collect personal information from your computer. Below are some basic examples of how your computer could become infected with a Trojan horse.
A site offers a free download to a program or game that normally costs money. Downloading the pirated program or game lets you illegally use or play, however, during the install, it also installs a Trojan horse on the computer.
A popular screen saver website has become infected or uploaded infected screen savers. Downloading the screen saver to your computer also installs a Trojan horse onto the computer.
You receive an e-mail that appears to be from a friend asking you to view this fantastic new program or look at a file. Opening the file infects your computer with a Trojan horse.
A friends Facebook account is hacked and has sent personalized messages telling all their friends to see this exciting new video. Opening the video requests a download with a hidden Trojan horse that infects your computer.