These programs spread in a computer network and, like viruses-"companions", don't change files or sectors on disks They penetrate the computer's memory from a computer network, calculate network addresses of other computers and send their own copies to these addresses Such "viruses" (Worms are not viruses in the strict sense) sometimes start files on the system disks, but can't apply themselves to computer resources (with the exception of main memory) generally
Worms are like a viruses in that they try to copy (replicate) themselves over the network and onto another computer through an unprotected shared folder or directory The Loveletter virus is really a worm written in Visual Basic Script programming language and its filename ends in VBS This worm is included in an e-mail attachment with the filename LOVE-LETTER-FOR-YOU TXT vbs