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Business in Vancouver: News that works for you

    Stronger computer viruses are emerging but there are ways to avoid catching them


    by Alan Zisman (c) 1996 First published in Business in Vancouver ,  Issue #357 August 27, 1996   High Tech Office  column

    It used to be that, despite media hype such as the Michelangelo scare a couple of years ago, computer viruses were relatively rare--especially among businesses that used some common sense. It wasn't impossible for your company's computer to get infected, but a much more typical victim was a kid swapping floppies with pirated copies of games.

    Since last year, though, a new type of virus has emerged, aimed specifically at users of common business applications. And while traditional viruses either required that you run an infected application, or start up your computer with an infected floppy in the disk drive, all it takes to infect your computer with one of these new-style viruses is to read an infected data file. And because they're passed on in your data, some of these viruses can even pass between different types of computers--from a PC to a Mac, for example.

    These viruses have been made possible because many applications include powerful macro-languages. Sophisticated users can use them to create customized macros--add-ins that let your word processor, for example, do much more than simply display a business letter.

    But that very power allows virus creators to use those same macro-languages to hide code in a document that allows the virus to spread itself onto your computer, and to copy itself into any new document that you read or write. As a result, the virus can spread to still more users, as your document is shared over your network.

    The first macro virus, Concept, infected Microsoft Word documents, and appeared about a year ago. Since then, there have been several more viruses infecting Word files. Recently, a new virus named Laroux became the first to infect spreadsheet files created with Microsoft Excel. However, it only affects Windows Excel versions 5.0 through 7.0--earlier versions of the program, along with Macintosh versions, are currently safe.

    Both Microsoft and virus specialist McAfee are distributing tools to detect and remove the Laroux virus from Excel data files, and these are available for free from their Web sites (www.microsoft.com and www.mcafee.com). As well, Microsoft says that you can manually identify infected data files by holding down the shift key when opening files in Excel (this prevents auto-load macros from being run). From the Tools menu, you would then choose Macros, and check for any of the following macros: Auto_Open; Check_files; PERSONAL. XLS!auto_open; or PERSONAL.XLS!check_files. If any macros with those names are found, they should be deleted from that menu item, with the changes saved to your file.

    The same steps can be used in Word to check the macros listed there. If any seem unfamiliar to you, you may want to delete them.

    There are a number of other steps you can take to minimize the risk of infecting your computer with these sorts of viruses.

    For example, if you receive a document, you may want to view it rather than immediately opening it in an application like Word or Excel. Windows 95, for example, includes a QuickView option, which you may already have installed. If you do, all you have to do is use the right mouse button to click on the file name, and QuickView will be one of the options in the pop-up menu. This allows you to view the contents of a file without loading it into its parent application. Windows 95's QuickView supports a dozen or so file types. QuickView Plus, a much more sophisticated utility, supports more than 200 different PC and Mac file types, and costs about $30. (Check their free, time-limited version at http://www.inso.com/). For Word documents only, Microsoft also distributes a free WordView utility on its Web site.

    Virus-checking programs have added the detection of most Word macro viruses. Get one and use it. Note, however, that these programs are always a month or so behind the latest viruses. And with new strains of viruses every week or so, it's important to update your program's data regularly. Symantec's Norton AntiVirus posts a free update on-line each month; shareware programs like McAfee's VirusScan or Frisk F-Prot are updated every two or three months. Make sure that you have the latest version for the most complete protection.

    At this point, macro viruses seem to be limited to Microsoft Office applications. Perhaps this is the result of Office owning 90 per cent of the market for application suites.

    Regardless of the reason, you shouldn't let these viruses keep you from using your computer to get your work done. Do take the necessary precautions.



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Alan Zisman is a Vancouver educator, writer, and computer specialist. He can be reached at E-mail Alan