To generate information or data about a file that can be used to verify the integrity of the file at a later time. Cleaning disks infected with a link virus requires a specific approach. Every file virus can incorporate different techniques to improve the infection rate or to avoid detection. Each of the above viruses can be memory-resident, can have stealth capabilities, can use encryption or can use a polymorphic engine. Technically another form of parasitic virus, the thing that makes macro viruses rate a class of their own is that they are transmitted as an executable component in an otherwise non- executable data file.
Macros are executable code intended to automate tasks in applications.
However the underlying macro language is extremely powerful, and can call out to external programs, making macro viruses potentially quite dangerous. Another way of looking at it is that they depend on Word as their platform. They arrive attached to a spreadsheet or document, when the file is opened it will transfer from the document to the application template. Any new files that are subsequently created will have the virus inserted as a standard macro. As sequence is used, i.e. to save a newly created file or using Save As to save a different version of an existing file.