"Traces of the Stealth_c Virus have been found in memory. Reboot to a clean system disk before continuing with this installation." This was the message staring back at me from one of the computer monitors at my office. Questions raced through my mind. "Stealth_c?" "What's a system disk?" "How am I supposed to install anti-virus software if the computer system already has a virus?"
As a discouraging feeling of helplessness came over me, I thought of all the people who had loaded something from disk on this box or who had used this box to access the Internet. Because there was no virus protection in the first place, it was going to be very difficult to determine how many floppy disks and hard drives had been infected. I wished I had learned about computer viruses a long time ago. What is a computer virus, anyway? Is it a computer with a cold? A computer "virus" is called a virus because of three distinct similarities to a biological virus. They are: ? They must have the ability to make copies of, or replicate, itself. ? They must have a need for a "host," or functional program to which it can attach. ? The virus must do some kind of harm to the computer system or at least cause some kind of unexpected or unwanted behavior. Sometimes computer viruses just eat up memory or display annoying messages, but the more dangerous ones can destroy data, give false information, or completely freeze up a computer. The Stealth_c virus is a boot sector virus, meaning that it resides in the boot sectors of a computer disk and loads into memory with the normal boot-up programs. The "stealth" in the name comes from the capability of this virus to possibly hide from anti-virus software.
Virtually any media that can carry computer data can carry a virus. Computer viruses are usually spread by data diskettes, but can be downloaded from the Internet, private bulletin boards, or over a local area network. This makes it extremely easy for a virus to spread once it has infected a system. The aforementioned Stealth_c virus was transported by the least likely avenue; it was packaged with commercial software. This is an extremely rare occurrence, as most software companies go to great lengths to provide "clean" software. There is a huge commercial interest in keeping computers virus-free. Companies stand to lose literally thousands of dollars if they lose computer data to a virus. An immense amount of time can be lost from more productive endeavors if someone has to check or clean each computer and floppy diskette of the virus because, no matter what, it will continue to replicate itself until it uses every bit of memory available. To service this market, companies sell anti- virus software, which scans programs, searching for viruses. If one is found, a user can "kill" it by cleaning the file, delete the file itself, move the file to a disk, or ignore it.
Ignoring a possible virus is an option provided because some of the newer software utilizes heuristic algorithms to detect possible viruses. This method of detection is highly effective but, because of the sensitivity of the programs, false hits can occur. It is also very important to keep your anti-virus software current. By some estimates, forty to one hundred new virus programs are written every week by less than ethical programmers. Most software companies put out new "vaccines" every month.
It is like an ongoing battle, the bad guys write a new virus or even a new "species" of virus, the good guys get a copy from some poor soul whose computer has been infected, and they write a vaccine. Some of the more paranoid, or perhaps astute, have theorized that the companies writing anti- virus software and the programmers writing viruses are one in the same. However, the author of a computer virus means nothing to one whose machine has lost data or has crashed due to infection. Detecting and deleting the virus becomes the immediate action needed. This is impossible without anti-virus software, and would be much simpler if the software is already installed on a system. So, keep your computers "vaccinated," because, it is contagious.