Posted by Donna (63.20.108.191) on March 20, 2001 at 11:04:19:
I was very confused about viruses and asked my son
if he would give me a explanation of what a computer
virus was.
He told me that there were basically two types of files
on all computers (executable files and data files).
.exe files contain instructions for your computers CPU.
.exe files are programs like word processors, computer
games, etc.
All other files are data files. Data files include
pictures, word processer documents, etc.
My son is aware of two types of viruses. The first
type, called an .exe virus, is like a mini-program
that inserts itself into other programs on your
machine, changing their behavior. There are also
similar viruses that infect system files which he
has grouped into this class.
The second type is called a macro virus. A "macro" is a
script stored in a data file that can be executed by
a word processer with macroing capabilities. This
script contains commands that simplify some word
processing tasks.
A macro virus is a macro that contains maliscious
commands.
There are also programs called "Trojan Horses" that
can be downloaded, and when run do damaging things
to your computer. These are sometimes called viruses
by people who don't know better. Worms are Trojan Horses that replicate themselves by copying themselves from place to place.
So, your machine can be infected by viruses by 1. down-
loading a useful program that's been infected by an
.exe virus, 2. downloading a macro virus and opening it
with a word processer capable of running macros.
Similar damage can be done to your machine by downloading a Trojan Horse or Worm and running it.
Hope this helps.