The macro virus is commonly found in spreadsheets and Microsoft Word documents.
It is easier to create and modify Macro viruses than other virus types, and documents are more widely shared than programs, especially with instant e-mail distribution. It is also very easy to ìcatchî such a virus just by opening an infected document.
Any application that is used on many platforms can carry macro viruses. For example, Microsoft Word is available in Microsoft Windows computers and Apple Macintosh computers.
Some well known macro viruses
Laroux
Laroux is the first Microsoft Excel macro virus discovered in the wild. Excel Macro viruses are written in Microsoftís Visual Basic for Applications macro language. This language is supported in Microsoft Excel for the Macintosh 5.0 and later, as well as numerous PC versions of Excel on Windows platforms.
Laroux uses the ìauto_openî and ìcheck_filesî macros to replicate. It creates a hidden, blank worksheet in infected documents, but it is not intentionally destructive. Laroux does not infect or spread on Macintosh systems, but Macintosh systems can harbor infected files in a multi-platform environment.
Word Macro Family (including Concept)
The macro language in Microsoft Word is used to write Word Macro viruses. This language is supported in Microsoft Word for the Macintosh 6.0 and later, and on Microsoft Windows platforms.
These Word Macro viruses consist of a set of macros contained in a Word template document. All of these viruses take advantage of Word features that allow macros to execute automatically or override menu commands. While an infected document is open, one of its macros is triggered, allowing the virus to copy itself into Wordís global template file. Subsequently, while uninfected documents are open, a virus macro in the global template file may trigger and copy the virus into the document.
Other macros may be used to cause damage or interfere with the normal operation of the computer. These viruses spread among all platforms that can run Microsoft Word. Your Macintosh can be infected by transferring Word files to and from DOS, OS/2, Windows, or other non-Macintosh platforms.
The first Word Macro strain to receive attention was Concept, also known as Word Macro 9508. This virus is common because several thousand infected CD-ROMs were widely distributed before its discovery. New, more destructive strains often appear.
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