Trojans Backdoors

A computer Trojan horse is used to enter a victim's computer undetected, granting the attacker unrestricted access to the data stored on that computer and causing immense damage to the victim. Trojans propagate, for example, when a sender sends an animated .GIF file with a Trojan in it and the recipient opens the file. The Trojan enters the recipient’s system and slowly causes extensive damage to the system. A common use of a Trojan horse is to install backdoors to allow the attacker to access the compromised system in the future.