© Copyright 2008 Pine Valley Computer Services Ltd. All rights reserved. |
Web design and hosting by
M9 Corporation
Viruses – Part One: What are they?
December 1, 2008
A lot of people are confused with what exactly a virus is. Quite simply, a computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user (en.wikipedia.org/wiki/computer_virus).
Computer viruses have been around for a lot longer than most people realize. The first virus was created in 1949 by Jon von Neumann. In the 1950’s, the virus “came to life” in a game called Core Wars. However, viruses did not really become a threat until the 1980’s when computers started becoming common place. At first computers became infected by floppy disks, then progressed to networks and finally to the Internet as a means of dissemination.
For a virus to infect a computer is really very simple; the only thing that has to be done is to open the file and the rest is history. Once the file containing the virus has been opened, the first thing the virus does is replicate itself. This can be done by either attaching itself to another program or as an e-mail attachment. The file is then spread and the whole process starts again. If that was the extent of the action by the virus, the only thing that you would have to concern yourself with is that it was taking up space on your hard drive. Unfortunately, viruses contain a payload that can sometimes cause serious damage to your files or the computer itself.
There are many different types of viruses. One of the most prevalent is the macro virus. This type is sent as a file with a macro embedded in it or as an attachment. Once the macro has been opened, it will execute and spread. These will infect documents or document templates and can cause substantial damage to a system by turning off security programs, or cause unusual behavior to your computer.
Memory-resident viruses work by corrupting files or program when they are opened and stored in the computer memory. File infector viruses attach themselves to the file that opens the program and can corrupt the program itself. Boot viruses are not seen very much anymore as they are usually passed around by floppy disks. These viruses swap themselves for the program the starts the computer. If you have a boot sector virus, there’s a good chance your computer won’t even start.
Have you ever been surrounded by a bunch of bad guys all at once? That’s kind of what a multi-partite virus is. This type will infect the computer by different methods and can attack programs and files at the same time.
Computer worms and the dirt-loving worms are quite similar. They get into your computer, and then move to the next one. Their method of travel is usually by an e-mail. All you have to do is open it up and it will then attach to more files and move again. One of the main effects is how it can slow down your network to a crawl.
Just like in Helen of Troy, Trojan Horse viruses act the same way. These are spread by what appears as a safe program such as a screen saver or a game. Once you install the program on your computer, the payload or virus that was installed with it starts to work. One of the most common effects is to install a backdoor to your computer for a hacker to hijack or snoop on your computer.
Do you have a bank account that I can have complete access to? If I sent you an email telling you that I can share with you a million dollars if you give me your account number, you have been hit by a hoax. Another way of getting to you is that you receive an e-mail telling you that you have been infected and that if you delete a certain file, you will clean your computer. Usually what happens is that you now have damaged your computer yourself by following the instructions in the e-mail.
The last one is not really a virus in itself, but makes you the virus. Remember the old chain letters that told you to mail ten copies to your friends and for each of your friends to mail ten friends. If you don’t do that, then you will have bad luck. When you do this through your e-mail, basically you become the virus. If you multiply that by ten each time you send out the e-mail, you can imagine how congested your network can become. Just remember, no one has ever gotten an incurable case of acne from not sending out a chain letter or e-mail.
The next issue will cover what to do if you have a virus and how to help protect yourself.
Computer viruses have been around for a lot longer than most people realize. The first virus was created in 1949 by Jon von Neumann. In the 1950’s, the virus “came to life” in a game called Core Wars. However, viruses did not really become a threat until the 1980’s when computers started becoming common place. At first computers became infected by floppy disks, then progressed to networks and finally to the Internet as a means of dissemination.
For a virus to infect a computer is really very simple; the only thing that has to be done is to open the file and the rest is history. Once the file containing the virus has been opened, the first thing the virus does is replicate itself. This can be done by either attaching itself to another program or as an e-mail attachment. The file is then spread and the whole process starts again. If that was the extent of the action by the virus, the only thing that you would have to concern yourself with is that it was taking up space on your hard drive. Unfortunately, viruses contain a payload that can sometimes cause serious damage to your files or the computer itself.
There are many different types of viruses. One of the most prevalent is the macro virus. This type is sent as a file with a macro embedded in it or as an attachment. Once the macro has been opened, it will execute and spread. These will infect documents or document templates and can cause substantial damage to a system by turning off security programs, or cause unusual behavior to your computer.
Memory-resident viruses work by corrupting files or program when they are opened and stored in the computer memory. File infector viruses attach themselves to the file that opens the program and can corrupt the program itself. Boot viruses are not seen very much anymore as they are usually passed around by floppy disks. These viruses swap themselves for the program the starts the computer. If you have a boot sector virus, there’s a good chance your computer won’t even start.
Have you ever been surrounded by a bunch of bad guys all at once? That’s kind of what a multi-partite virus is. This type will infect the computer by different methods and can attack programs and files at the same time.
Computer worms and the dirt-loving worms are quite similar. They get into your computer, and then move to the next one. Their method of travel is usually by an e-mail. All you have to do is open it up and it will then attach to more files and move again. One of the main effects is how it can slow down your network to a crawl.
Just like in Helen of Troy, Trojan Horse viruses act the same way. These are spread by what appears as a safe program such as a screen saver or a game. Once you install the program on your computer, the payload or virus that was installed with it starts to work. One of the most common effects is to install a backdoor to your computer for a hacker to hijack or snoop on your computer.
Do you have a bank account that I can have complete access to? If I sent you an email telling you that I can share with you a million dollars if you give me your account number, you have been hit by a hoax. Another way of getting to you is that you receive an e-mail telling you that you have been infected and that if you delete a certain file, you will clean your computer. Usually what happens is that you now have damaged your computer yourself by following the instructions in the e-mail.
The last one is not really a virus in itself, but makes you the virus. Remember the old chain letters that told you to mail ten copies to your friends and for each of your friends to mail ten friends. If you don’t do that, then you will have bad luck. When you do this through your e-mail, basically you become the virus. If you multiply that by ten each time you send out the e-mail, you can imagine how congested your network can become. Just remember, no one has ever gotten an incurable case of acne from not sending out a chain letter or e-mail.
The next issue will cover what to do if you have a virus and how to help protect yourself.
Subscribe to the Pine Valley Computer Services Ltd. Newsletter
Subscribers will receive our fact-filled newsletter in their email so they can benefit from the information and resources we can provide.
If you have anything you would like to see included in an upcoming newsletter, please contact us.