A Trojan Horse is a malicious program that disguises itself as a useful, harmless program. For example, a free instant messaging program that records keyboard input to obtain passwords, credit card numbers, etc would be considered a Trojan Horse.
In computing, Trojan horse, or Trojan, is any malicious computer program which is used to hack into a computer by misleading users of its true intent. The term is derived from the Ancient Greek story of the wooden horse that was used to help Greek troops invade the city of Troy by stealth.
Trojans are generally spread by some form of social engineering, for example where a user is duped into executing an e-mail attachment disguised …