Definition: Named after the Trojan Horse of ancient Greek history, a trojan is a network software application designed to remain hidden on an installed computer. Trojans generally serve maliciious purposes and are therefore a form of malware, like viruses.
Trojans sometimes, for example, access personal information stored locally on home or business computers, then send these data to a remote party via the Internet. Alternatively, trojans may serve merely as a "backdoor" application, opening network ports to allow other network applications access to that computer. Trojans are also capable of launching Denial of Service (DoS) attacks. A combination of firewalls and antivirus software protect networks against trojans.
Trojans are similiar to worms. In contrast to worms and viruses, however, trojans do not replicate themselves or seek to infect other systems once installed on a computer.
Also Known As: malware
