Questions about Malware

Q: What are malware, viruses, spyware, and cookies, and what differentiates them?

A: Let us take the easy one first. "Malware" is short for malicious software and is typically used as a catch-all term to refer to any software designed to cause damage to a single computer, server, or computer network, whether it's a virus, spyware, et al.

Q. What exactly is a virus? Is a "worm" also a virus?

A: Viruses are computer programs or scripts that attempt to spread from one file to another on a single computer and/or from one computer to another, using a variety of methods, without the knowledge and consent of the computer user. A worm is a specific type of virus that propagates itself across many computers, usually by creating copies of itself in each computer’s memory.

Many users define viruses simply as trick programs designed to delete or move hard drive data, which, strictly speaking, is not correct. From a technical viewpoint, what makes a virus a virus is that it spreads itself. The damage it does is often incidental when making a diagnosis.

Obviously, any incidental damage is important, even when authors do not intend to create problems with their viruses; they can still cause harm unintentionally because the author did not anticipate the full effect or unintentional side effects. The most common method used for spreading a virus is through e-mail attachment. Sending a virus, even if designed to be harmless, can cause unforeseen damage.

Q. How can I prevent a virus from infecting my computer?

A: A virus scanner is the most common tool for prevention. This utility attempts to scan a computer program before it runs, and if it recognizes the signature of a malicious code, it shuts it down. Many scanners also evaluate programs to determine if it contains any virus-related characteristics.

The best way to stop viruses is to use common sense. If an executable computer program is attached to your e-mail and you are unsure of the source, then it should be deleted immediately. Do not download any applications or executable files from unknown sources, and be careful when trading files with other users.

Q. What is a "Trojan Horse"? Isn't this a virus by any other name?

A: I have heard some arguments that Trojan Horse malware is a virus subset (and vice versa) but there are differences worth mentioning.

A Trojan Horse meets the definition of virus that most people use, in the sense that it attempts to infiltrate a computer without the user’s knowledge or consent. A Trojan Horse, similar to its Greek mythological counterpart, often presents itself as one form while it is actually another. A recent example of malware acting as a Trojan horse is the recent e-mail version of the "Swen" virus, which falsely claimed to be a Microsoft update application.

Trojans typically do one of two things: they either destroy or modify data the moment they launch, such as erase a hard drive, or they attempt to ferret out and steal passwords, credit card numbers, and other such confidential information.

Trojan Horses can be a bigger problem than other types of viruses as they are design to be destructive or disruptive, as opposed to viruses and worms where the coder may not intend to do any harm at all. Essentially this distinction does not matter in the real world. You can lump viruses, Trojans, and worms together as "things I don't want on my computer or my network".

Q. How do I prevent a Trojan Horse attack?

A: The methods for dealing with Trojans are generally the same as for those for dealing with viruses. Most virus scanners attempt to deal with some of the common Trojans with varying degrees of success. There are also specific "anti-Trojan" scanners available, and your best weapon is common sense yet again. Score another point for safe computing!

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