Basic Virus Information
This page is intended as a general guide to viruses. It is not perfect and some literary licence has been used to simplify the explanations. It is not intended to be a technical explanation, but a general background for the average or newbie computer user.
What is a virus?
A computer virus is a small computer program which makes your computer perform some unintended action (generally bad). They were given the name 'virus' because of their similarity to the biological viruses that we humans suffer from, and this is possibily the best way to understand them. Like biological viruses, your computer can catch them by contact with another infected computer and their effects may be anything from mild to 'fatal'.
In reality, a computer virus is a small computer program that is designed to interfere with your computer to a smaller or greater degree, and to pass itself on to other computers.
In its mildest case, the virus may show a small display on the screen such as a line of text or a graphic or a fireworks display. This may occur either on startup, or depending on time or whether a particular program is run.
In its worse case, the virus may delete files from your disk, or modify you computer enough to make your computer totally useless.
Some viruses are specific to the type of computer hardware you are using. That is, Intel based or MacIntosh, and some are specific to the Operating System that is running on the computer (e.g. DOS, Windows 3.1 or Windows 95/98).
Also some viruses are specific as to which programs they 'attach' themselves to (or use for transmission) so that some users may be vunerable and others not. For example, one virus only attacks a particular brand of word processor files and is transmitted by transferring document files between users. So, if you don't use that particular word processor, you are safe from this virus (but not the other 50,000). In another case, the virus only affects users of a particular email program. Obviously the writers of these viruses will try to attach them to the most common products rather than less well used products. However, maybe half the viruses are independent of the programs that you are using.
Some viruses are separate programs and can be identified by their name. Other viruses are embedded in other programs and can only be identified by comparing the size of the file with the size of the original uninfected file.
How does your PC catch a virus?
All viruses are caught by contact.
If you never swapped data/programs with any other computer or user, you would never catch a virus.
Occasionally a commercial product is supplied already infected with a virus. This is so rare that it can be disregarded. Buying commercial programs is by far the safest way to protect yourself.
Previously common causes of infection were the floppy disks you and your children swapped with other people either with data or programs on them. Just viewing the contents of the floppy disk may be sufficient to infect your computer. Up until the last couple of years, this was the major way that viruses were transmitted.
Today the most common form of transmission is over the internet. Friends send you a cute screensaver or game that they have found. The screensaver/game may have a virus (specific to that screensaver/game) embedded in it. Or it may be that the sender is infected and that the virus has embedded itself in all that sender's programs, so anything they send you may carry the virus.
Recent viruses have infected email programs so that they automatically send out emails with enticing subjects like 'Here is the data you wanted' and include the virus in a attachement.
Where are you likely to catch a virus from?
In summarising what has been said above, you will most likely catch a virus as attachments to emails, by downloading programs from the web from doubtful sites, and to a lesser degree, by sharing data/programs by floppy disk .
Being on a Rootsweb mailing list is safe as the size of binary attachments that can be sent through their mailing list computers is so small that it cannot contain a virus .
Downloading programs from reputable sources such as microsoft.com is also safe, but downloading from unknown sites is very risky.
What if I get a virus?
Rule #1 is "do not pass it along".
I have heard a number of horror stories of what not to do. One person in a high profile business emailed all his business contacts to warn them that he had a virus. The company's customers were not impressed by his enthusiasm. In another case, a person suspected that he had contacted an email virus, and so sent an email to the computer staff at the local school asking for confirmation. He still wonders why they didn't respond and won't talk to him.
So, if you suspect/know you have a virus, isolate your computer and don't pass it along to others. If you suspect that you have already passed it along, contact the victims by other means (e.g. phone) and warn them.
There are a number of sites that can give you information on a virus, but the problem is in trying to identify which particular virus you have, so that you know what to look for. The addresses given on the the main virus page, may help you identify which virus you have and even have instructions to remove it.
A better approach, is to immediately go out and buy an antivirus program, install it, go online and update it (as it may have been packaged 6 months ago, before your particular virus was written), and then use it to check out your system.
As soon as you are completely satisfied that you have cleaned up your system, contact the people that you have given/sent files to, and let them know what has happened. Do not pretend that nothing has happened.
Virus warnings and hoaxes.
Nearly as common as actual viruses, are the virus warnings that well meaning people send to all the lists they subscribe to. Most of the hoax warnings begin with referencing a third party, such as ' A friend (who is an expert with computers) has told me ....' or ' A friend just received this letter from Microsoft (or some other authority) .... and I thought I would pass it on ....'. Such a person has no personal knowledge of the virus and is just passing on rumours which their source generally has no better idea about.
In fact some hoaxes are as dangerous as viruses. A recent hoax warns people that they may have a virus, but that the virus cannot be detected until it matures on a soon-to-occur date. It then asks people to search for a certain file on their computer and delete it if they find it. Unfortunately the file is a crucial Windows file that most people need for their system to run correctly.
For those warnings that are not hoaxes, the situation is not much different. If people follow the protection techniques described on the the main virus page, receiving an occasional warning about 1% of the thousand of viruses that are written each year, won't make much difference. If they do not follow the protection techniques, then chances are, they will disregard the genuine warnings.
To summarise, posting of virus warnings to lists is most strongly discouraged, because most are hoaxes, or the warnings are superfluous for those that are properly protected, or ignored by those that have no protection. If you believe that you have some 'important' virus info that 'must' be shared with the list, send it to the list administrator, and ask them to consider forwarding it to the list.
You are our 1543 visitor since 29th May 2001.
Last updated on 31 May 2001