www.drinky.org.uk - How to Avoid Computer Viruses

The Beginners Guide to How to Avoid Computer Viruses

I'm sick of all these new viruses, here's how to avoid them and stop them spreading around

First of all, don't use Windows operating systems. 99% of viruses are written to exploit Windows faults or people that don't take proper care of their Windows systems. If you know what you're doing, use Linux, Mac OS or any other Unix type operating system.

If you use Windows you can reduce your vulnerability by following the following simple methods.

First regularly update Windows using the Windows Update feature. This is at the top of your Start Menu. Install any critical updates.

Use Anti-Virus software. For home use, use Norton Anti-Virus, McAfee Virus Scan, or Trend PC-Cillin. Anti-Virus software is one of the few things worth actually paying for. Make sure you use something. If you really don't want to or can't afford to buy software, use Grisoft's AVG free virus scanner as it's perfectly adequate.

Use a firewall. Some of the most recent viruses randomly attack insecure systems via an open Internet connection. I won't go into the details, but a good firewall will block these. Zonealarm is free to download, easy to set up and is excellent. If you use broadband, you should definitely install Zonealarm, though you may be better off installing Smoothwall on an old unused PC. Smoothwall is a Linux firewall system, which means it isn't vulnerable to Windows attacks. However, it is a dedicated system and it will wipe the hard disk of the machine you install it on, so don't use it on a machine you need for anything else.

Smoothwall 1.0 will run comfortably on a 486 or early Pentium with 32MB RAM and a 500MB hard disk. Version 2.0 requires a low end Pentium with a no less RAM or disk space than version 1.0, though 64MB RAM and a 1GB HD is recommended. There is documentation on the website to explain it all.

Don't use email software. That’s Outlook, Outlook Express, Eudora, Mozilla Mail or whatever else you use. They download all of your email and then run anything contained within them when you read them unless explicitly set up not to. This is a common way of spreading viruses. Most Internet Service Providers (aka ISPs - the people you have your internet connection with) provide free email accounts for use within one of the above programs. Don't use them. However, with the previous suggestions, periodic checking of these accounts for important email from your ISP shouldn't be too dangerous. To avoid loads of junk mail (known as Spam) you can use a Spam filter like Spam Assassin or Mail Washer to sort through your mail and get rid of any suspicious ones.

My best advice is to use web-based email, such as that provided by Yahoo, though I would avoid Hotmail and MSN as Spammers target them. Yahoo is by far the best email service available. Most webmail providers will virus scan your mail for you, though some may slip the net so you still need to be careful.

Whatever you use, be very cautious when opening mail. Don't open it unless it looks ok. Classic worry signs are senders that don't seem to have a sender’s address or name, mail that feature a series of random characters in the sender’s address and those which contain part of your own address. Just delete them, don't even open them. Be as trusting as you would when inviting people you don't know into your house.

Mail-viruses often pretend to be people you know, the most successful viruses at this time have been Klez and SoBig.F did this. I got several copies sent to me claiming to be from people I know, fortunately I knew what I was doing, so still be careful when accepting attachments from people you know. I even had some replies from companies I had never emailed claiming I had sent it to them. Be wary of unusual file types (this is the 3 letters after the '.' in the file name). Sobig.f used .pif and .scr files pretending to be screensavers amongst other things. Be suspicious if the mail promises too much. Famous ones were I Love You and one which claims to be nude pictures of Anna Kournikova. These people know how to make you open something you shouldn't, it's called 'social engineering' and designed to get people to attract enough interest to get you to run the virus. This is becoming a bigger problem as more and increasingly intelligent viruses are released. Make use of the virus scan facility provided by the mail provider before you download it. Virus scan it again with your own virus scanner before you open it. Some viruses are designed around certain virus scanners and so can avoid detection that way, so using both opportunities to scan them is a good idea.

Any email attachment claiming to be a critical software update from Microsoft is definitely a virus so don't open them, just delete them straight away. Microsoft don't distribute software updates by email for this very reason. They just claim to be Microsoft so people will run the virus.

Avoid putting your email address on web pages. In some cases it is unavoidable, it will be done for you without you being able to do anything about it, but avoid posting your address if you can. That includes message boards, mailing lists, homepages etc. Most Spam is generated by addresses being collected from web pages. Avoiding Spam can help you avoid viruses.

Don't use the Windows Address Book. If you are unlucky enough to get infected by a virus, some of them use the Windows Address Book to send themselves out to people you know.

Keep your security software up to date. That’s Windows Update, your virus scanner and your firewall. You can set up your virus scanner to automatically check for updates, Windows XP will automatically look for Windows updates and you should check for Zonealarm updates every week or so. If you use Smoothwall, you should check it every few days to refresh the updates list and check for updates via the updates page and look for evidence of attacks successful attacks via the logging facility.

Learn more about security. To be honest, the techniques used to attack computers will make your mind boggle so read a computer magazine once a month to slowly pick up info. PC Advisor is a good one to start with. PC Plus and Personal Computer World are more advanced.

Be vigilant :)

So, if I made your head spin, here's a summary.

Use Windows Update.
Use a virus scanner.
Use a firewall.
Keep them updated.
Don't use insecure programs like mail readers and Windows Address Book, use Yahoo Mail instead.
Don't open any emails that look suspect or have unusual files in them.
Be wary of emails that seem over familiar for people you don't know.
Delete any that contains part of your own email address or random character sequences as part of the sender’s address. Delete anything that doesn't appear to have sender’s name or address.
Delete anything that claims to be a software update from Microsoft.
Delete anything you aren't sure about without opening it.
Be wary even if you know the sender.
Virus scan any attachments both on the mail website and after you download it.
Be paranoid to start with, eventually you be able to tell the difference and can worry less.
Read a PC magazine to learn tips.

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