i/s Back Issues

Volume 12

No. 3  January/February 1997

Q: What are macro viruses and how are they different from other computer viruses? How can I protect my files from them?

A:  Macro viruses use an application's macro programming language for 
transmission. Unlike earlier viruses, they infect documents, not 
programs. They are also the first cross-platform viruses: they can be 
transmitted between PCs and Macintoshes. You can receive infected files 
via diskette, the Internet, or email attachments.
 
Microsoft Word has been the target of roughly 180 macro viruses (there's 
also one well-known Excel virus). While early versions of these viruses 
have been relatively harmless, the newest strains can destroy data.
         
A well-known macro virus is the Concept virus, which changes an ordinary 
Microsoft Word 6 file to a template file that you can no longer alter. 
The virus then infects new Word documents as they are saved. It also 
infects existing documents if you save them with the Save As command.
         
To protect against viruses, including macro viruses, install the latest 
version of Dr. Solomon's Anti-Virus Toolkit. This site-licensed software 
is available to all MIT faculty, staff, and students via the Web. 
You can download the Toolkit for your platform from the MIT Information 
Security Office home page at
         
         http://web.mit.edu/security/www/
         
         Be sure to bookmark this Web page. To protect against new viruses, 
you'll need to download Toolkit updates at least once a quarter.
         
For more in-depth information on Word macro viruses, go to
         
         http://www.drsolomon.com/vircen/macrovir.html
         
         If you have questions about viruses or think you have a virus on your 
machine, contact the Computing Help Desk at x3-1104.
         

i/s Home |  i/s Back Issues |  Volume 12 |  No. 3