Worm or Virus...What's the Difference?

Everyone has been infected with a virus at one time or another either through the common cold or the flu. A virus attacks the human body by entering through one of the many openings and attaching itself to a host cell. It releases a piece of genetic information into the cell and recruits the cell’s enzymes to propagate the genetic information. Once the genetic code has been adequately replicated, it destroys the cell and attacks cells nearby.

How does a computer virus simulate a biological virus? Just as a biological virus injects its own genetic information into a cell and interferes with the body’s normal operations, a computer virus is a program written to interfere with the proper functioning of a computer. It may damage programs, delete files, reformat hard disks and perform other forms of destructive acts.

To be classified as a virus, a program must meet two criteria. It must be able to execute itself by placing its own code in the execution path of another program. The program must also be able to replicate itself by replacing existing computer files with copies of the virus-infected files. Similar to the way a biological virus requires a host cell, a computer virus requires an infected host file to propagate itself.

Viruses have become the villains of the computer world, propagating themselves and destroying everything in their path. However, another tool of destruction, known as the worm, has been creeping into the computer industry. Most of us have heard of the dreaded Blaster worm that attacks Microsoft websites, but what exactly is a worm and how does it differ from a virus? Actually, a worm is a type of virus that attacks the computer in a method differing from the way a typical virus attacks a computer. Unlike the typical virus, the worm does not require a host program to propagate. A worm enters a computer through a weakness in the computer system and propagates itself using network flaws.

The typical virus requires activation through user intervention, such as double clicking or sending outgoing email. However, a worm releases a document containing the “worm” macro and sends copies of itself to other computers through network flaws, therefore bypassing any need for user intervention.

So, what can you do to protect your computer from virus infection? There are a number of preventative measures that you can take. For example, you can purchase and continually update virus scan software. Make sure that this software contains the “real-time” scanning feature which monitors all incoming and outgoing mail. You may also install a firewall which prohibits unauthorized access to your computer. By installing these preventative devices, you can proactively defend against viruses.