Definition of a Trojan Horse Virus
Today, there are viruses and there are Trojan Horses. However, there is no such thing as a “Trojan virus”. Actually, the real definition of each prevents the chance of the virus’ being such a thing. Trojan doesn’t replicate but Viruses do. That truth alone implies there could never be a “Trojan Horse virus”.
The description of Visa continues with this message, “A Trojan Virus is an e-mail virus commonly released by an e-mail attachment.” Well, not so. A Trojan could be sent with the attached file in e-mail, but it is definitely not an e-mail virus. (Actually, there are some true e-mail viruses, but that is another whole topic). Therefore, it may or may not go with e-mail, and it is equally possible to have been downloaded from websites or resulted from P2P file transfer. Therefore, vectors have nothing to do with either something is or is not a Trojan.
What is a Trojan then?