This document is intended to inform the average, non-technical user on the subject of viruses. What they are, how to avoid getting them, how to avoid being affected by them, and how to avoid transmitting them. This document specifically addresses Microsoft Windows users. Please redistribute this document’s address as widely as possible. Feel free to included it in your email signature or to link to it from your website. For a list of anti-virus software, please check here.
About viruses in general
What is a computer virus?
A virus [?] or worm [?], or trojan horse [?] (hereafter referred to as “a virus” for the sake of simplicity) is a small piece of software that is generally designed to disguise it’s true nature, to be run without the computer user’s knowledge and perform some action that a user would most likely not have authorized. It’s a form of vandalism.
What is a computer virus not?
It’s not mysterious. It’s not smart or independent, nor has it free will. It’s just a program like your favourite text editor. Viruses aren’t to be feared, most of the time they are merely a nuisance to be dealt with. On occasion, hoever they can cause irreparable damage by deleting or altering data (your documents or programs). Dealing with a virus has the same weight as keeping a bee out of one’s home- It’s a necessary task to be dealt with promptly but without undue alarm.
How do I get viruses?
A virus is a file just like any other. It gets on your machine in exactly the same way any file gets on your machine. These days, viruses are transmitted mostly though email attachments. They can still be transmitted though floppy disks, CDs, hard drives or infected files. They can transmit themselves though your local area network as well. In exceedingly rare instances, they are placed on your machine by crackers [?] (uninvited people who access your machine though the internet).
How do they work?
Like any program, such as a game or word processor, a virus must be launched, activated, before it can do It’s thing. Double clicking on a file, or launching a file or program that contains a virus will make it run. This means that until you deliberately wake it up, or have an automatic program wake it up, it simply sits on your disk. Inactive. Most viruses these days rely on the Microsoft scripting system to wake it up for you or trick you).
As one can see, It’s not magic. It just that someone has given a little thought as to how to abuse your machine’s vulnerabilities and your trust in the software you use. Fortunately, knowing this allows us to practice the four D’s: Detect, Disinfect, Defend and Discuss.
DETECT: How do I know if my computer is infected?
It’s not always easy to know if you have been infected by some sort of virus. Here are some common tell tale signs. A good rule of thumb is this: If you feel that you might have a virus, check!
- Your machine inexplicably slows down
- Your machine appears to be active though you haven’t set it to task.
- Programs that usually work well inexplicably fail to start.
- Your machine inexplicably shuts down or re-boots.
- You may have received an email from someone asking you check your system for viruses (an excellent practice, actually).
- Perhaps your in-box contains a large number of emails that have been unsuccessfully sent.
- Disk space seems to be inexplicably filling up.
- Files are mysteriously appearing where you know they shouldn’t be.
- Files have sizes that aren’t commensurate with their type (ie: An MP3 sound file takes less than 50 kilobytes)
The only real way to know if you have a virus on your computer is to install anti-virus software such as is listed later on in this article.
I recommend that you do however, purchase the software on CD unless you are familiar with downloading files, saving them, and installing them from your system.
DISINFECT: How can I remove viruses from my computer?
Though this segment is the shortest, it contains the most valuable piece of information that can not be over-repeated. Unless you are a well trained expert with deep knowledge of your operating system, viral algorythms and have a deep passion for rooting around the deep inner guts of your computer, the answer is simple: Get thineself a good quality anti-virus program. Isolate your computer, run your checker from It’s installation CD if possible.
What anti-virus software do you recommend?
You can easily find a list of anti-virus software vendors. I use Norton Anti-Virus on my PCs because it has an automatic definition updater and scheduler. It’s also the first I’ve tried and it works for me. I don’t promote it above another, because I haven’t tried others. I also use Virex on my Mac for the same reason. Please choose the one that best meets your needs and budget. Do make sure that the vendor updates the virus definitions on a very regular basis. An anti-virus package with out of date definitions is useless.
DEFEND: Keeping virus-free
Avoid using Microsoft products
This includes Microsoft Windows, Microsoft Outlook, Microsoft Outlook Express, Microsoft Office or any component thereof. Avoid using documents created by any of these packages such as .doc (Microsoft Word documents) and .xls (Microsoft Excel documents), as they are notorious for containing, transmiting and activating viruses.
This may not be an option for some. The next is to ensure that your Microsoft system has no contact with the internet if possible. Keep it behind a firewall [?] (a piece of software or hardware that acts like a protective buffer between you and the internet.)
Use a good anti-virus program, and update its definitions (the list that tells the anti-virus program what to look for and how to fix it) on a daily basis.
Staying virus free also means being careful about where you go on the Internet and keeping your security settings in the medium to high range.
To be on the safe side, it is better to not download any email attachments unless you are expecting it, and have confirmed that it is indeed from the sender. Antivirus software is pretty good, but it isn’t infallible.
DISCUSS: An additional approach
The technical details have been well discussed. There’s is another very important dimension to keeping yourself virus free. People.
It is people who run and maintain the computers that interact with yours to create a network. People write viruses. People write anti-viral software. People report new viruses. Point this article or one like it to a friend. Inlcude a pointer in your email signature. Discuss it with someone who is more skilled with computers than yourself. Discuss it with someone who is less skilled.
If you’ve receieved a virus from someone, Share it gently. It may not have come from them as the FROM line is often faked. Change the subject line. (Remove any attachments!) It may not have come from them, but ask them to send a pointer this article to everyone on their email list. In other words, reverse-trace the path of the virus with knowledge. The network of machines is reflective of the network of people. Let’s use it to inform, educate and help each user gain greater immunity to computer viruses. Remember that if you stop one single virus, you may be preventing 1000 other people from getting it. Your action might have an incredible impact on the network. What if Typhoid Mary had never passed on her bug?
Keeping the net safe, one person at a time
Imagine this: A friend or business partner tells you the following story. “I had a meeting with my most important clients to propose a deal that could bring me enough money to change my life, and that of everyone in the company. Everyone worked on the proposal for weeks, every fact checked, every detail sweated. The next day, when it was time to print out our incredible piece of work, I tried to open the document. It wouldn’t open. The meeting is in 4 hours, and the document is gone. Weeks of work for the most critical proposal of our careers, and it’s been destroyed by a virus. We lost everything.
Now imagine discovering that the virus was sent from your machine.
Let your machine be the very last machine that a virus ever sees.
Eradicate and Eliminate: it’s the thing to do! We’ve mentionned the signs, steps to take and the precautions to take. We’ve mentionned discussing virus prevention with others. When you’ve received a virus (that your anti-virus software has eliminated, because your definitions are up-to-date, aren’t they?), please respond to the sender of the email informing them of it. Urge them to read this article, or one like it, and to take action. If every computer is the last one a virus sees, only a very few will ever see it. That adds up to the Internet having “a strong immune system”. The safer you keep your neighbour, the safer they can keep you. I urge you to take action. Create a standard form-response [example]. Include a call to action in your email signature. [example]
Once you’ve done reading this article, if you would like more detail, I highly recommend the following article: Computer virus prevention: a primer
More resources on the net
Sophos Virus Info. Sells anti-virus software. Has excellent research material.
Symantec Security Response. Sames as above. Sells anti-virus software. Has equally excellent research material as well as security related materials.
McAfee’s Virus Info Library
The AVP Virus Encyclopedia
The A-Z Antivirus Page
The Hitchhikers AntiViral Resources
Virus Help Discussion List