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What is a computer virus?

Get the basics on computer viruses: Part 1


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What does it mean?

Trojan horse
A program that appears to be useful or harmless but that contains hidden code designed to exploit or damage the system on which it is run.

virus definition
Also known as a virus signature. A recognized pattern of unique computer code contained in a virus.

Computer viruses are software programs designed to interfere with computer operation deliberately. They record, corrupt, or delete data. They spread themselves to other computers through local networks and the Internet, often slowing things down and causing other problems as a result.

Just as human viruses range in severity from the 24-hour flu to the Ebola virus, computer viruses range from the mildly annoying to the downright destructive. The good news is that with an ounce of prevention and a little knowledge, you are less likely to fall victim to computer viruses, and you can diminish the impact if you do get one.

How do viruses work?

Basic viruses typically rely on unwary computer users to inadvertently share or send them. Some viruses that are more sophisticated, such as worms, can replicate and send themselves automatically to other computers by controlling other software programs, such as an e-mail sharing application.

Certain viruses, called Trojan horses, can falsely appear as a beneficial program to coax users into downloading them. Some Trojans can even provide expected results while quietly damaging your system or other networked computers at the same time.

Although it's good to be aware of these different types of viruses and how they work, what is most important is that you keep your computer software current with the latest updates and antivirus tools, stay informed about recent threats, and that you follow a few basic rules when surfing the Internet, downloading files, and opening attachments.

Once a virus is on your computer, its type or the method it used to get there is not as critical as removing it and preventing further infection.


Related topics

To learn more about viruses, read the other topics in this series:

·          How do I know if a virus has infected my computer?

·          How do I remove a virus?

·          How do I protect my computer against viruses?



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