CertiGuide to A+ (A+ 4 Real)  9  Chapter 4: Diagnosing and Troubleshooting in the Windows OS

ConfigSafe 1 Protecting Your Computer from Viruses

The name virus sometimes leads to wrong associations. A computer virus is nothing more than a computer program. It is a computer program whiich was made to annoy you, not help you like other useful programs. Viruses can do more harm then just annoy you, they can delete your files, make your files publicly available, make your system unusable, there is even a chance a virus can harm your hardware. . These malicious programs are a big threat because they have many means to spread themselves. They are resident parasites, they stay in computer’s memory and are work in the background while you are doing something else, say reading via e-mail, for example. A virus can send to e-mail address it found in your address book or it collected while you were surfing the web.

Viruses are usually an .exe type of program, but they can attach themselves to other .exe programs, they “infect” executable files. That makes another way of spreading viruses, and this makes a virus much harder to control. There is a type of viruses, which target Microsoft Office files. Office documents can have programs, called macro programs. Those programs are simpler then regular executable programs; they are born to help automate some task in Office. Macro programs can also be made malicious by macro viruses. Trojan horse is a name for a malicious program (virus) which was made to look like some legitimate program. Recently, there is another type: polymorphic viruses. A virus is called polymorphic if it can change its code. This is not hard to detect a virus by matching patterns of code, which is the most important detection weapon antivirus software which is known as heuristics.

ConfigSafe 1 Protecting Your Computer from Viruses