Macro Viruses

Contrary to popular belief viruses are not difficult to write. However, you do, or rather did, need to know assembler. While it is possible to write a virus in a high level language, and in fact a number have been written, they tend to be rather large and thus noticeable.

From the anti-virus point of view this was a good thing since it limited the number of people who were capable of actually writing viruses. You had to know something about programming to write them, or even changing them.

But, ever since computers were invented people have been trying to make programming languages easier to use. In addition the software publishers have been trying to make their applications both more powerful and easier to use. The latest innovation is the advent of macro languages within applications. The idea is that the macro language will enable the user to customise the application to do exactly what they want. Not only that but where a company has multiple applications they tend to use the same macro language for all applications. And, since the macro language is designed to be used by users rather than programmers, it is easy to use.

The result is that it is very easy to write a virus in a macro language.

In a lot of cases that is not a major problem since the macros are stored separately from the data. However some applications eg Word, store the macros with the data. Add that to fact that data is copied from machine to machine on a regular basis and you have the virus writers dream.