Melissa: the virus that shut down company email

The story

On March 26, 1999, a Word document was posted to an online discussion group, promising a list of passwords for adult websites. It contained a macro, a small program that runs inside the document.

When someone opened it, the macro used their email program to send the document to the first 50 people in their address book, with the subject line “Important Message From” followed by the victim’s own name. Each of those recipients saw a message from someone they knew.

Within days, the flood of messages overwhelmed mail servers. Large companies and government agencies shut down their email systems to stop it. The author, David L. Smith of New Jersey, was caught within a week, and later served time in federal prison. He had named the virus after a dancer he knew.

Why it mattered

The FBI described Melissa as the fastest-spreading computer infection at the time. It disrupted about a million email accounts and led some organizations to suspend email entirely. It was an early warning about programs hidden in documents, a trick attackers still use.

The lesson today

Melissa established a pattern that lasted for two decades: a document that looks like information but carries instructions. Attackers used Office macros so widely that Microsoft eventually changed Office to block macros in files downloaded from the internet by default.

The lesson is broader than macros. Documents, links and attachments that arrive from a known contact can still be dangerous, because the contact’s account may be the thing that was compromised.