In essence, a worm is like an advanced virus. It replicates and spreads itself but it happens on a larger scale. What makes worms more dangerous is that they do not require any human action to replicate and spread. A worm is always looking to exploit security vulnerabilities in networks and operating systems and spread itself. In fact, most worms are designed only to spread and don’t attempt to change the host computer or system which they enter and spread through. This does not mean worms are without danger however. Being infected by a worm may result in your computer being used as part of a botnet to send spam e-mails. Some of the more common ways worms spread are by e-mails, weak networks and attachments.