Melissa, a macro virus, spawned the age of virus infection due to opening attachments sent through email servers. The victim would open their email and then download the document onto their hard drive. The macro would then infect the computer system, gather information, and send it back to its originator. The infection would spread to other computer systems basically by taking over the email address services for those infected. The virus would also gather the email addresses within contact files in order to send the virus macro to another computer to further the infection. Macro viruses of this time are the reason why anti-virus programs scan incoming email messages on your computer system for known viruses such as Melissa.
The important lesson to take away from these attacks is throughout the years new vulnerabilities were discovered. Through research and analysis of these vulnerabilities, software engineers have created new techniques to protect the networks. The trick here is to learn these techniques, and apply them to your network’s security.