Melissa

This is a well-known Internet worm, which spreads by e-mail. It comes attached to e-mail messages and looks like a text document. However, when a user opens such attachment, the worm installs itself to the computer and starts to spread. It modifies Microsoft Word settings and infects lots of text documents. Then it sends out infected documents attached to e-mails. These actions can disclose user's personal documents and other confidential information. The worm sends out huge amount of infected letters and can overload mail servers.