Worms are a special kind of malignant file that replicates itself from computer to computer, instead of just from file to file like viruses. So while a virus can spread across all of the files on one user's computer, a worm can transmit itself to other computers via a user's network or email system!

How do Worms work?
Worms are generally embedded in programs or attachments to email messages. When the user opens the file, the work begins a two-part attack on the system. First, the worm performs its damage, such as destroying files, corrupting programs or damaging the operating system. Then, the virus uses a process known as replication to transmit itself to everyone in the infected user's email address book. If the computer is not on the internet at the time, then the transmission could be stopped; however, with the increasing number of users who have 'always-on' connections via DSL or cable-modems, the worm is usually able to transmit itself to thousands of unsuspecting recipients in a flash!

Worms can also infect Microsoft's Active-X and Sun's Java script controls, which means that worms can be embedded in web pages and launch themselves upon visitors who simply visit the site and view the web page! While this has rarely occurred to date, it is a distinct possibility in the future that simply browsing the web could be very dangerous without adequate antivirus protection!

A popular worm virus was the Melissa Virus, which came via an email that said "IMPORTANT MESSAGE FORM (user)" in the subject line. When it was opened, Melissa tried to send itself out to 50 people in the user's address book. Other viruses, like the HAPPY99 virus did the same thing, except they modified the user's operating system registry making programs unstable at the same time. The I love you virus deleted all of the user's .jpg files first, then replicated itself to the user's address book recipients. The list goes on and on...

The Scariest thing about Worms
The scariest part of worm attacks is that they are usually invisible to the infected user. Worms work silently in the background, and if they do not actually damage obvious files in the user's computer, they go undetected for a long time while they continue to transmit themselves to recipients via email. Worms can be avoided by employing up-to-date antivirus software as well as paying attention to daily tech news; because worms spread to many users very quickly, the public awareness of these attacks is greater faster than normal individual-attacking viruses. Usually, worms can be stopped by informing users each morning of any new threats that are going around cyberspace.