Defining Malware
What exactly is a virus? Is a "worm" also a virus?

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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.

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

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".

How do I prevent a Trojan Horse attack?

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! Try our trojan detection software

Do some websites use cookies to exploit user information?

Unfortunately, yes. Some may deceive users or omit their policies. For example, they may track your Web surfing habits across many different websites without informing you, and then use this data to customize the advertisements you see on websites, etc., typically considered as an invasion of privacy. It is difficult to identify this and other forms of "cookie abuse," which makes it difficult to decide if, when, and how to block them from ones system. In addition, the acceptable level of shared information varies between users, so it is difficult to create an "anti-cookie" program to meet the needs of everyone.

How does spyware exploit user information?

The spyware problem is similar to the cookie problem from the point of view that both are an invasion of privacy, although spyware is different from cookies, technically speaking. Spyware is a program that runs on your computer and, again, tracks your habits and tailors these patterns for advertisements, etc. Because it is a computer program rather than just a bit of text in a cookie, spyware can also do some nasty things to ensure that the spyware keeps running and keeps influencing what you see.

How do I know if spyware is running on my computer?

You can use our detection program PestBlock. Similar to antivirus software, this program compare a list of known spyware with files on your computer and can remove any that it detects.

How does spyware install itself on computers?

Common tactics for surreptitious installation include rolling up advertising programs into "free" shareware program downloads, and once the spyware is installed it can download advertisements 24 hours a day and overlay them on websites and programs you are using.

Can spyware send tracked information to other people?

Some forms of spyware monitor a target’s Web use or even general computer use and sends this information back to the spyware program's authors for use as they see fit. To fight this kind of problem, a spyware removal tool is obviously helpful, as is a firewall that monitors outgoing connections from your computer. Other forms of spyware take over parts of your Web browsing interface, forcing you to use their own search engines, where they can track your browsing habits and send pop-up advertisements to you at will. The biggest concern regarding spyware is that most of them are poorly written or designed. Many people first realize their computer is running spyware when it noticeably slows down or stops responding, especially when doing certain tasks such as browsing websites or retrieving e-mail. In addition, poorly written spyware can often cause your computer to function incorrectly even after it has been removed.

Some information for this page has been taken from web site Microsoft Corporation