What is a computer virus?

A computer virus is a small software program that spreads itself to other executable software when it is run. It may infect only your computer, or it may replicate itself and use your address book to send itself to additional victims.

Why are viruses dangerous?

When a virus runs, it may:

• Damage your system
• Steal your identity information
• Infect files that you send out
• Send itself to everyone in your address book, with your return address
• Hijack your PC and Internet connection and use them to send spam or launch denial-of-service attacks

Computer viruses and other forms of malicious software ("malware") cause billions of dollars of damage each year and untold anguish for victims of identity theft.

How do viruses get on my computer?

In most cases, viruses and other malicious software can enter your system only if you run the executable code. As a result, virus purveyors use a variety of ruses to trick you into running the code. They may:

• Hide it inside another program or file, such as a screen saver, game, or even a mock security product.
• Ask you to click a Web link in an email, an IM, or on a Web site; merely clicking the link can install the malicious code. Or they may embed it in an innocent-looking Word document.
• Disguise their email with the address of someone you know. Or someone you know and trust may forward a file to you, now knowing that it’s infected.

Why is Microsoft Word vulnerable?

Microsoft Word files contain executable programs (called "macros") written in a high-level programming language that is part of Word itself. Macros are preprogrammed shortcuts—either preset or customizable—that automate tasks such as applying bullet lists or formatting a particular style.

Hackers can use that same programming language to write viruses. When someone sends you a Word file by email, it may contain not only the text, but also an embedded macro virus. The virus automatically activates when you open the file.

The best-known Word macro virus is the "Melissa" virus, first discovered in 1999. Melissa was delivered via email in an attached Word document. When the attachment was opened, the virus sent itself to everyone in the user’s email address book. Melissa generated massive email traffic that clogged and shut down email networks.

Does Symantec have a product that protects against viruses in Microsoft Word files?

Yes. Norton Internet Security (and other Symantec products containing Norton AntiVirus™ technology) protects against Word macro viruses. Norton scans all email attachments for viruses and removes the virus before it can infect your system. Norton also prevents you from unknowingly sending infected attachments to others.