What’s a computer virus?

This post follows up on the two-minute tech tip I recorded for Episode 251 of the Just the Books podcast.

Viruses differ from bugs because they can spread. They copy themselves and then move on to infect a new computer, while they once spread through physical media such as floppy disks, they now tend to piggy-back on emails and hide in website links.

There are a few more terms you should know:

  • Malware is the generic term for all malicious software.
  • A Trojan horse pretends to be a nice program while really it is malicious. Those popup ads that say “Your computer may be infected, click here to install our security check now!” are often Trojan horses.
  • A worm is different from a virus because it doesn’t need the user to do something to infect others, such as forward an email. Worms most often take advantage of known bugs in computers to spread.

There are more, but this is only an introduction!

The Flashback virus that recently infected lots of Macs came from WordPress sites that were themselves not updated. There are two layers to this problem:

  1. Self-hosted WordPress sites (not wordpress.com sites) were running out-dated versions of WordPress. There are many reasons why this happens that I’ll cover in future posts, but by not having the most secure and up-to-date installation it allowed the virus to pretend to be an Adobe software update (it was a Trojan).
  2. A vulnerability (a bug) in Java on Macs allowed the virus to run. Apple released a software update to fix Java.

Could this have been prevented? I think by keeping every computer, including those running wordpress up-to-date would have definitely reduced the reach of the infection. Learning about how to take care and use technology would have reduced it further. Is there a possible world without virus attacks causing widespread infection? Yes, but it requires time and education.

Three steps to keep your devices healthy:

  1. Keep your computer up-to-date.
  2. Install virus protection software. There are some small trades-offs to doing this. To be more secure the software has to run all the time and that will mean your computer will run just a tiny bit slower. Will you notice? Probably not. Keep this virus protect up-to-date. Do not schedule these updates monthly, do them daily.
    • Microsoft has Security Essentials.
    • Macs have their own Security tools.


      Can these be your only line of defense? Yes, but I like a two-layered approach.

    • Choose and install your software from a reputable source. Who is a reputable source? The big names such as Norton, McAfee (note: it only has one F!), and F-Secure. There are free options too, Avira, Avast, and AVG come to mind.
      Please do not click ads while you are web surfing that say “You’re computer is infected click here for a free security scan.” I’ll cover phishing soon.
      Does installing and keeping this software updated mean you definitely will not be infected? No, but they will reduce the likelihood by a significant amount.
  3. Be smart with what you do. Don’t click every link and open every attachment, especially if you aren’t expecting a file and the context doesn’t seem to indicate there should be an attachment. Do not install software from unknown sources. Who’s an unknown source? I’ll cover digital credibility and expand upon safe surfing in future posts.


    Here’s a bonus fourth step:

  4. Backup, Backup, Backup. How? Everyway you can. I will cover data organization/backup/archiving in the future but there is a concept called LOCKSS, Lots of Copies Keeps Stuff Safe. While this concept is generally geared toward large institutions, I’ve scaled it down for individuals for years. Of course this doesn’t work if the copies themselves are infected but there are a few ways around it. I’ll cover this in more detail in the future but my quick method is:
    • Copy/Duplicate the file. Paste it right in the same spot.
    • Convert it to another format, for example, it’s a word processing document, print it to PDF.
    • Email it to a spare email account or a trusted friend. I’ve been accepting friend’s final thesis papers and dissertations for years.
    • Make CD/DVD/USB key copies of the files.
    • If it is that critical and important to your future (or past) print it out! You can always scan it and while it might not be the perfect original (in the case of a photograph, for instance), wouldn’t you rather a paper copy and a later scan of that image instead of no copy?

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