Worm attack

A computer worm is a program containing malicious code that attacks host computers and spreads via a network. Network worms exploit security vulnerabilities in various applications. Due to the availability of the internet, they can spread all over the world within a few hours of their release.

Most worm attacks (Sasser, SqlSlammer) can be avoided by using default security settings in the firewall, or by blocking unprotected and unused ports. Also, it is essential that your operating system is updated with the most recent security patches.