What are Viruses, Trojans and Worms?

A Virus is a piece of code usually disguised as something else that causes some unexpected and usually undesirable event to occur on the system. Viruses are often designed so that they automatically spread to other computer users. One way that they may be transmitted is through e-mail attachments.¹

A Trojan (or Trojan horse) is a malicious program that pretends to be a benign application. It is designed to cause your computer to do something that is unexpected and usually undesirable. Since it does not spread (is not self-replicating) it is not really a virus.² The Trojan is usually the "wrapper" that carries the virus.

A Worm is a parasitic program designed to replicate itself on your computer and then spread to other computers via email (through your address book) or an IRC (chat program). Worms are designed by coders for advertising agencies to gain lists of legitimate email addresses for use in marketing.² They can also be designed to slow down networks (generate network traffic), thus giving other competitors an edge in their fields. Though this is not always the case, mostly they are just designed to create TCP/IP & SMTP chaos.

References

1. http://www.majorgeeks.com/glossary.php

2. http://www.cyberangels.org/virus/

3. http://www.symantec.com/

Return to Laptop/Desktop Support | Return to Main Support Page | CBI Home