What is a Trojan?

A Trojan is malware that performs unexpected or unauthorized, often malicious, actions. The main difference between a Trojan and a virus is the inability to replicate. Trojans cause damage, unexpected system behavior, and compromise the security of systems, but do not replicate. If it replicates, then it should be classified as a virus.

A Trojan, coined from Greek mythology's Trojan horse, typically comes in good packaging but has some hidden malicious intent within its code. When a Trojan is executed users will likely experience unwanted system problems in operation, and sometimes loss of valuable data