November 18, 1999

Computer viruses, and macro viruses in particular, are in the news often these days. Every few weeks, you hear about another virus making the rounds, often erupting from within an innocent looking document. Someone in your own organization might forward a spreadsheet to you, not knowing that the document is infected.

To help protect yourself and your organization from data loss caused by macro viruses, make sure that all of the macros created in your organization are digitally signed. When a digital signature is attached to a macro, the macro comes from a trusted source. This helps to ensure that the document has not been tampered with and that opening it will not spread a virus throughout your organization.

Use digital signatures in Office 2000

With Microsoft Office 2000, you can take advantage of digital signatures when creating macros for your organization. You can even make this security feature transparent to users.

When users open an Office 2000 document that contains a digitally signed macro, the Security Warning dialog box appears. To choose to trust all macros signed by the source, users select the Always trust macros from this source check box.

If you sign all of your macros, and have users select the Always trust macros from this source check box when they open one of your documents, they will not see the warning for your macros again. Only untrusted sources, or potential virus risks, trigger the warning after that point.

Digital signatures can also help you determine whether to trust a potentially dangerous document from outside your organization. If the document is signed, and the person or organization that signed it is trusted, you can be more certain that the document is virus-free.

Get more information about security in Office 2000

The Microsoft Web site includes several papers and articles that provide information about security in Office 2000. The following documents address macro viruses and digital signatures:

• Introduction to Security

  A good introduction to security issues and digital signatures, with useful links to other articles, downloads, and Web sites.

• Outlook 2000 E-mail Security Update Administrative Update

  An Office Update white paper that describes how to use Office 2000 to help protect against macro viruses.

• Digital signatures and certificates

  An Office Web site article with information on obtaining and using digital certificates with Office documents.

• Managing and Supporting Office 2000

  A collection of topics in the Office 2000 Resource Kit that covers scanning for macro viruses, setting security levels in Office applications, and digitally signing macros.