McAfee AVDCDE-BA-CA User Guide - Page 7

Preface What happened? If you've ever lost important files stored on your hard disk, watched in dismay as your computer ground to a halt only to display a prankster's juvenile greeting on your monitor, or found yourself having to apologize for abusive e-mail messages you never sent, you know first-hand how computer viruses and other harmful programs can disrupt your productivity. If you haven't yet suffered from a virus "infection," count yourself lucky. But with more than 50,000 known viruses in circulation capable of attacking Windows- and DOS-based computer systems, it really is only a matter of time before you do. The good news is that of those thousands of circulating viruses, only a small proportion have the means to do real damage to your data. In fact, the term "computer virus" identifies a broad array of programs that have only one feature in common: they "reproduce" themselves automatically by attaching themselves to host software or disk sectors on your computer, usually without your knowledge. Most viruses cause relatively trivial problems, ranging from the merely annoying to the downright insignificant. Often, the primary consequence of a virus infection is the cost you incur in time and effort to track down the source of the infection and eradicate all of its traces. Why worry? So why worry about virus infections, if most attacks do little harm? The problem is twofold. First, although relatively few viruses have destructive effects, that fact says nothing about how widespread the malicious viruses are. In many cases, viruses with the most debilitating effects are the hardest to detect-the virus writer bent on causing harm will take extra steps to avoid discovery. Second, even "benign" viruses can interfere with the normal operation of your computer and can cause unpredictable behavior in other software. Some viruses contain bugs, poorly written code, or other problems severe enough to cause crashes when they run. Other times, legitimate software has problems running when a virus has, intentionally or otherwise, altered system parameters or other aspects of the computing environment. Tracking down the source of resulting system freezes or crashes can drain time and money from more productive activities. Beyond these problems lies a problem of perception: once infected, your computer can serve as a source of infection for other computers. If you regularly exchange data with colleagues or customers, you could unwittingly pass on a virus that could do more damage to your reputation or your dealings with others than it does to your computer. User's Guide vii