Stiller Research’s Introduction to Viruses

Welcome! This is the first of a series of pages where I’ll give you what you need know to make sure that your PC is safe from viruses and all the other threats that may damage your programs and data. In these pages I’ll explain exactly what viruses are, how they work, and how to protect against them.

Viruses are actually very simple. Once you understand exactly what they can and cannot do, it’s much easier to take appropriate precautions. While we’ll be spending most of our time talking about viruses, I’ll also cover the threats that are much more likely than viruses to damage your programs and data. Although I’ll occasionally touch on some rather esoteric or complex topics, you won’t need to be a “techy” to understand this text or to find it useful in your day-to-day use of your computer.

I will go one step at a time and I will explain all the concepts and jargon clearly before I use the terms. I’ll also focus on practical information that will help you protect your PC. Everyone should benefit from reading these pages; those of you that are experts will be able to skip the background information, yet I will still explain everything clearly for those of you that are new to PCs.

Let me quickly introduce myself. I am Wolfgang Stiller, the primary developer of Integrity Master, a leading anti-virus and data integrity package for the IBM PC. Most of my comments therefore are specific to the IBM PC but don’t worry if you are on another platform, the general virus principals hold true for any computer.

You may be wondering why you should bother to read this text. You already have anti-virus software on your PC, so why should you need to actually understand any of this stuff?

One reason is that your anti-virus software may not be giving you the protection you think it is. You’ll learn how to determine what your software can and cannot do. Another reason is that viruses are but one threat to your programs and data; I’ll explain how to protect yourself fully.

You may even be wondering if viruses are really worth worrying about at all. Do you think you’re safe because you rarely download software or buy only from a trusted retailer? Are viruses really a serious threat to your PC or are viruses mostly hype? Let me begin by quickly putting this issue into perspective.

Viruses and anti-virus programs are not really the mysterious, complex, and hard to understand software that many people consider them to be. Not only can these programs be understood by anyone, but these days, it’s critical that we all fully grasp how they work so as to to protect ourselves.

What Do Viruses Do?

I’m going to present an easy to understand but detailed explanation of viruses and other types of malicious software. For now, it’s enough to understand that viruses are potentially destructive software that spreads from program to program or from disk to disk. Computer viruses, like biological viruses, need a host to infect; in the case of computer viruses this host is an innocent program.

If such a program is transferred to your PC, other programs on your PC will become infected. (I’ll shortly explain in more detail how this happens.) Even though some viruses do not intentionally damage your data, I consider all viruses to be malicious software since they modify your programs without your permission with occasional disastrous results.

The bottom line is that if you have a virus, you are no longer in control of your PC. Every time you boot your PC or execute a program the virus may also be executing and spreading its infection. While most viruses haven’t been written to be destructive, almost all viruses can cause damage to your files–mostly because the viruses themselves are very poorly written programs. If viruses destroy nothing else, they destroy your trust in your PC–something that is quite valuable.

Are Viruses Mostly Hype?

Unfortunately not! There is some confusion about this issue because some extreme claims have been made regarding numbers of viruses and how likely you are to become infected. During the Michelangelo media extravaganza in early 1991, some exaggerated figures were presented in the media which led some people to suspect that all viruses were nothing but hype. One company was quoted in Information Week that based on their reports, one out of four PCs was infected every month! (I won’t speculate on the motivation for these type of claims.)

You may also hear reports of there being from five to ten thousand different PC viruses with the number expected to double in six to nine months. So, are we faced with impending doom? No, not quite. The truth is viruses are very wide-spread but a relatively small number (about fifty) account for ninety percent of all infections. Most of the five to two thousand viruses are so poorly written that they will not spread in the real world.

Many of these viruses are created by kids that can’t even program. They use automated viruses creation programs that produce very poor quality viruses. These viruses are so obvious that they rarely spread in the wild. Still, viruses are a real threat that we can’t afford to ignore. Viruses have been found on brand-new PCs, direct from the manufacturer, and on shrink-wrapped software, direct from the publisher. Viruses are not merely hype and no one is safe from potentially being infected. If you value your data and programs, you have to take some precautions.

How Serious Are viruses?

Viruses are a problem but they are not the main thing you should be concerned about. There are many other threats to your programs and data that are much more likely to harm you than viruses. Problems such as hardware glitches, software conflicts, software bugs, and even typos are much more likely to cause undetected damage to your data than viruses. A well known anti-virus researcher once said that you have more to fear from a spilled cup of coffee than from viruses. While the growth in number of viruses now puts this statement into question, it’s still clear that there are many more occurrences of data corruption from other causes than from viruses.

So, does this mean that viruses are nothing to worry about? Emphatically, no! It just means that we need to address the other threats to our data as well as viruses. Because viruses have been deliberately written to invade and possibly damage your PC, they are the most difficult threat to guard against. It’s pretty easy to understand the threat that disk failure represents and what to do about it, but the threat of viruses is much more difficult to deal with.