Home Computer Security Advice

Tom Van Vleck

Here is a short list of things to do about security for your home computer:

Briefly:

Back up daily.
Use a Mac.

  1. Back up your data to removable media. Copy your data so that everything you care about is stored in at least two places. This isn't just about security from bad guys: your hard disk might crash, or your computer might be damaged or stolen. Hard drives are made to last only a few years. If you have a CD or DVD burner, burn a backup disc often. If you have a Mac, you can hook up an external drive and turn on Time Machine.

    Of all the bad things that could happen to your computer, a disk crash is the most likely. A friend had a lot of great pictures in Photoshop on her hard drive, and then one day the disk was dead. She was lucky and got her files back. If you have anything important that's stored on just one computer, you should feel nervous.

  2. Understand that electronic mail can be forged and snooped easily. Don't assume that a message was sent by the person named in the From field. If you get mail that appears to be from a bank, or eBay, or the traffic court, or Paypal, asking you to go to a website and fill in your personal info,  it's probably a scam. Your electronic mail travels across the Internet unprotected; strangers can read and change it, so don't send personal details, valuable passwords, or credit card numbers in regular e-mail.

  3. Don't run or install programs from strangers. You'd think this is obvious, but many people don't understand that clicking on an email attachment often runs something. People get an email message claiming to be a picture, or whatever, and click on it, and  their computer gets all messed up. Be careful about clicking on email attachments, even if they appear to be from someone you know, because email can be forged easily (see above). Don't install programs sent to you in email or instant messages or from web pages. You may be installing "spyware" or "adware" or programs that silently use your machine to mail spam to others.

  4. Don't read email with Outlook or browse with Internet Explorer. Windows users should avoid using Microsoft Outlook. It has had many documented security holes where a bad guy sends a message that takes advantage of a bug in Outlook to install a virus on your machine, even if you don't open the message. There are plenty of other good free mail-reading programs such as  Thunderbird; use one.

    Internet Explorer on Windows has also shown a large number of exploitable security weaknesses. Just visiting a web page can infect your computer. I use  Firefox instead (it's free). Here's a  story by Aman Gupta, who got mail saying he had one of those electronic greeting cards: he clicked on the message and found that the website code tried five different ways to install a program on his machine that would steal his electronic banking passwords. (If you are an AOL or Earthlink user on a PC, you are probably using a re-branded Internet Explorer. You can use Firefox instead.)

  5. Use a firewall if you have a cable or DSL line. Get a combination NAT and firewall box, which should cost less than $50. My  Linksys BEFSR41 works fine; you can find newer units with more features. Even if you have only one computer, a firewall helps isolate your machine from the bad guys on the outside, kind of like a surge protector. (You can get programs that install on your computer to do supposedly the same thing, but a separate box is better.)

  6. Install a virus checker and keep its definitions up-to-date, if you are using Windows. (I'd say that even if I had not worked at a company that makes such things.) You should have a virus checker program, even though fast spreading viruses can hit you before you update.

    Windows users also need to obtain and use "adware" and "spyware" checkers.

  7. Install security patches from your software providers regularly. This is important, because many machines get infected by viruses that exploit holes for which patches have been available for months. Once again, though, you can't count solely on these patches for security, because the patches come out after the holes are found.

  8. Use a Mac. Macintoshes have far fewer security problems. According to a 2001 UK government report by  Satchell and Peeling, "There are about 60,000 viruses known for Windows, 40 or so for the Macintosh, about 5 for commercial Unix versions, and perhaps 40 for Linux." That was in 2001; since then there have been thousands more Windows viruses, and only a few Mac viruses.

    (Frankly, I am not really enthusiastic about any of the operating system choices. The Mac is better but by no means perfect. Windows, Mac OS, Linux, and other Unix descendants are all written in the C language. History shows that software written in this language often has security-related bugs. Brilliant programmers have failed to produce secure systems using this approach in many years of trying. We should do better.)

Further Reading

CMU CERT has a nice tutorial article about  Home Computer Security.

For more information on security, see this article about the  Top 20 Security Vulnerabilities.

Here's a good, but depressing, article about the situation by Scott Granneman:  Joe Average User is in Big Trouble. He also wrote  A Home User's Security Checklist for Windows.

If you insist on using Windows, Terry Gleidt wrote a nice how-to article on  Coping With Windows, and Gina Trapani wrote up how she  disinfected her mom's Windows box (took 3 days).

You may also be interested in how I filter spam.

Wireless

It's cool, it's convenient, and it's also risky: a neighbor can download a program that will crack your WEP key in about an hour, and you'll never know... till you get your bank statement! I have used wireless connections while traveling, but at home I stick to wire. If you really want to go wireless, you have to take responsibility for security. Nobody else will.

There are two issues: securing your router so strangers can't connect to your network, and securing your communication so that strangers can't intercept it.

If outsiders can connect to your network and use your bandwidth, they could

You can deal with strangers attempting to use your network by

The interception issue is harder to detect. The WPA-2 encryption standard fixes a lot of problems. At home, use only WPA-2, choose a long random passphrase, and change it occasionally. Remember that even if your connection to the access point is encrypted, electronic mail will then pass over the Internet unprotected.

Using "free" wireless is tempting. You may be traveling and have the choice of the hotel's $9.95/day wireless, or another access point that requires no password. The access point may be a fake hotspot, or "Evil Twin," set up by someone who wishes to observe your credit card numbers and banking passwords. People have been arrested for using other's wireless without permission.

If you are using a public access point,

(If you don't know what this means, maybe you shouldn't use wireless.)

Copyright (c) 2003-2008 by Tom Van Vleck

updated 17 Feb 2004, 12 May 2004, 08 Jul 2004, 01 Oct 2004, 10 Nov 2004, 07 Mar 2006, 06 Jan 2008

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