All About Computer Viruses

The computer is as slow as molasses. Your mouse freezes every 15 minutes, and that Microsoft Word program just does not seem to open. Maybe you have a virus. Just what exactly is a virus? What type is your computer? How is it there? How is it spread havoc and ruin that? And why is it bothering with your computer anyway? Viruses are pieces of code that make copies of themselves, or replicate, in the computer without asking your explicit written permission to do so. Forget getting your permission down on paper. Viruses do not bother to ask your permission at all! Very invasive. By comparison, there are bits of code that can replicate in the computer, say something your IT guy thinks you need. But the code spreads, perhaps throughout your office network, with your permission (or at least your IT guy permission). These types of replicating code are called agents, said Jimmy Kuo, a research fellow with McAfee AVERT, a research arm of antivirus software maker McAfee Inc. In this article, though, we're not the good guys or the cops. We will talk about the bad guys, the viruses. A long, long time ago in computer years, like five, most viruses consist of a similar breed. They performed on your computer perhaps through an email attachment or a floppy disk (remember those?). When they committed themselves to your files, say your Microsoft Word program. If your Microsoft Word program is opened, the virus replicated and attached itself to other files. These could be other random files on your hard drive, the files that are furthest from your Microsoft Word program, or other files, depending on how the virus writer wanted the virus to behave. The virus code contains hundreds or thousands of instructions. If it is a replica insert these instructions in the files it infects, said Carey Nach Berg, Chief Architect at Symantec Research Labs, an arm of anti-virus software maker Symantec. Corp With so many different types of viruses exist now, the kind just described is called a classic virus. Classic viruses still exist, but they are not as prevalent as they are used. (Maybe we can make classic viruses on the shelf with Hemingway and Dickens.) These days, in modern times, viruses are known to spread through vulnerabilities in web browsers, files shared over the Internet, e-mails themselves, and computer networks. Far as browsers are concerned, Microsoft's Internet Explorer takes most of the heat for spreading viruses because it is used by more people for web surfing than any other browser. Still, "Any web browser potentially has vulnerabilities," said Berg Nach. For example, let's say you go to a website in IE you have every reason to think is safe, Nach Berg said. But unfortunately it is not. It has virus code hidden in the background that IE does not protect you against. While you're looking at the site, the virus is downloaded onto your computer, he said. This is a way of catching a nasty virus. During the past two years, another common way of catching a virus is through downloads computer users share with each other, mostly on music sharing sites, Kuo said. On Limewire or Kazaa, for instance, teenagers or other music lovers may think they're downloading that latest Justin Timberlake song, when in reality they're downloading a virus directly into their computer. It's easy for a virus writer to put a download with a virus on one of these sites as one to share it with everyone. Here's one you might not have thought of. If you use Outlook or Outlook Express to send and receive email, you have a preview pane below your list of e-mails the contents of the e-mail you have selected shows? If so, you put yourself in danger. Some viruses, though a small percentage in Nach Mountain, are inserted straight into emails themselves. Forget opening the attachment. All you have to do is check your e-mail to a potential virus, Kuo added. For example, have you ever opened or viewed an e-mail stating that the "loading"? Well, if everything is "loaded", a virus in the e-mail can only be loaded to your computer. So if I were you, I'd click on View on the toolbar in your Outlook or Outlook Express and close the preview window. (You must click on View and then Layout in Outlook Express.) On a network at work? You could get a virus that way. Worms are viruses in your computer via networks, Kuo said. They travel from machine to machine and, unlike the classic viruses, although the machine itself rather than individual files attack. Worms sit in your memory, or RAM, Nach Berg said. OK, so we talked about how the viruses get into a computer. How they cause so much damage once they're there? Let's say you have a classic virus, one that replicates and attacks various files on your computer caught. Let's go back to the example of the virus that initially infects your Microsoft Word program. Well, it would eventually crash the program, Nach Berg said. It would also harm your computer as it looks for new targets to infect. This process of infecting targets and looking for new could end up using your computer's ability to function, he said. Often the destruction caused by a virus associated with a particular event or date and time, called a trigger. For example, a virus can be programmed to make dormant until January 28. When that date rolls around, though, it can be programmed to do something so harmless, but annoying as splash popups on your screen, or something as severe as reformat hard drive on your computer, Nach Berg said. There are other possible causes, but for a virus on your computer to malfunction or slow to act in bizarre ways. And that leads us to a new segment - the reason virus writers would want their time creating viruses in the first place waste. The majority of viruses are still written by teenagers looking for some notoriety, Nach Berg said. But a growing segment of the virus-writing population has other intentions in mind. For these other intentions, we need the "backdoor" concept to explain. The sole purpose of some viruses is to create a vulnerability in your computer. Once it creates this hole of sorts, or backdoor, it signals home to mama or dada virus writer (kind of an ET). Once the virus writer receives the signal, they can use and abuse of your computer to their own taste. Trojans are sometimes used to open backdoors. In fact that is usually their sole purpose, Kuo said. Trojans are pieces of code that you could download to your computer, say, a new group. As in the Trojan war it is named, they are usually disguised as harmless bits of code. But Trojans are not viruses because they are deemed not replicated. Now back to the real viruses. Let's say we have Joe Shmo virus writer. He sends a virus that ends up infecting thousands of machines. But he does not want the FBI on his case. So he instructs the viruses on the various machines to send their signals, obviously not on his computer, but a place that can not be traced. Hotmail email happens as an example of such a place, Kuo said. OK, so the virus writers now control these computers. What will they use them for? One use is to send spam. Once that backdoor is open, they bounce spam from those computers and send it to other machines, Nach Berg said. That's right. Some spam you receive in your e-mail now may originally have been sent to other innocent computers before it came to yours so that it could remain in disguise. If the authorities in tracing the original senders of spam, they were hard on spam itself. Spammers do not want that. Ever heard of phishing emails? Those are the ones who claim to be from your Internet service provider or bank. They typically request some information from you such as your credit card number. The problem is not your internet service provider or your bank. They are evil people after your credit card number! Well, these emails are often sent the same way spam is sent by sending them via innocent computers. Of course makers of anti-virus software using a variety of methods of attack to combat viruses. Norton, for instance, uses signature scanning, Nach Berg said. Signature scanning is similar to the process of looking for DNA fingerprinting, he said. Norton examines programming code to find what viruses are made of. It adds those bad instructions it considers its large database of other bad code. Then use this extensive database to find and match the code with similar code in your computer. When it finds such virus code, let me know you! 2004 by Kara Glover Feel free to reprint this article in newsletters and on websites, with resource box included. If you use this article, please send a brief message to let me know what was found: kara333@earthlink.net