Viruses and worms

Virus: A virus is a computer programme that spreads by infecting files. Standard viruses will spread only when an infected file is transferred from one computer to another.

Worms: A worm is a type of virus that propagates from machine to machine and also replicates without human intervention. Most worms spread as e-mail attachments. Worms generally affect Internet applications (i.e. e-mail, Internet Information Server) and it spreads very quickly. Through internet they can have a wide distribution.