Lesson 2: Virus Catagories
Macro viruses
According to Symantec macro viruses are the most common type of virus, and have cost companies the most money. In my years as a computer technician the only virus I was unable to completely eradicate from any network I was responsible for was a macro virus known as Ethan Frome. These viruses are easy to create, and easy to spread. Macro viruses infect document files, most commonly Microsoft Word, Power Point, Excel, and Access but it can infect any data file or document template file. Since Microsoft Word macro viruses are the most common, we will discuss how a macro virus spreads using word documents. This method of transfer is similar for all programs though. When an infected Word document is open the viral macro code copies itself to the default document template, this allows the virus to then spread to any document opened using the computer the infected document was opened on. Then when the file is sent to someone else via email or on disk and the person opens the file their Word default document template is infected and the cycle starts all over again. Generally speaking macro viruses are not particularly dangerous, they are more of an annoyance than anything.
An example of a macro virus is Ethan also known as Ethan Frome. Ethan Frome (the real Ethan Frome not the virus) is a well-known novel by Edith Wharton. The virus Ethan Frome is a simple virus less than 50 lines long. The virus spreads as described above, and it stores itself in a hidden file called Ethan____. Whenever a document opens there is a 3 in 10 chance that the virus will alter the document if this happens, the virus changes the title of the document to "Ethan Frome", Author to "EW/LN/CB" and company to "Foo Bar Industries Inc.". The most amusing thing about this virus is it checks to see if you are infected with another macro virus called the Class virus, if you are it removes the virus for you, or at least makes it unable to replicate.
