Using shared and public computers


What are the risks involved in using shared and public computers and how you can reduce them.

Using shared and public computers

Most people now have a computer at home with broandband access, maybe even access to one at work, albeit with limited or reduced access, and inbetween home and work we probably have access to the internet through our mobile phones or laptops via various wireless technologies such as wi-fi, gprs and 3G.

Some of us may have none of this, or maybe we find ourselves on the rare occasion needing to get online and finding that all that is available is a public computer such as one in an internet cafe or library, or a shared computer belonging to a friend or colleague.

What are the risks?

The risks of using a computer that does not belong to you is that you have no prior knowledge of the state of that computer. How good is its security? Is there any monitoring software or spyware on it? Is it infected with computer viruses? Can I delete or hide what I used the computer for from the owner? And so on.

In essence you have no control over the security aspects of the computer that you are temporarily using, and you also have no idea how secure your connection to the internet is and whether what you use the computer for and all actions are being recorded in some way.

How to reduce the risks

My personal recommendation for when forced to use a computer or access point belonging to someone else is not to use any web site or service that requires a login or your personal details. So no internet banking, no social networking, no email and so on. It's not worth the risk. Just wait until you can get back to your own PC.

If you don't own your own PC then I wouldn't recommend signing up for internet banking anyway, and as for social networking and email, if you really need it then I would recommend getting into the habit of running through the following checklist every time you use a shared or public PC:

  1. Check with the owner what security software is installed and running
  2. Open up the web browser and clear the previous users cache, cookies, history and downloaded files
  3. Make sure that any web site that you need to log in to is using a secure connection. If you are not sure, type an 's' after the http in the address bar and see if it works. Example:
  4. Make sure that you log out of all sites that you are logged into
  5. Only log in to one site at a time and never surf in another web browser window or tab while logged into a site as you could fall foul of a cross-site scripting attack
  6. When finished clear your web browser history, cookies, cache, etc and close down and restart the browser
  7. Never create bookmarks
  8. Never download or save files to the PC. If you need files from the internet then save them to a memory card or stick and virus check it often

Last word

With broadband coverage increasing it is less likely that we will need to use public and shared computers, but on that rare occasion when you have to, or where there is no alternative, use the computer as a research (look-up) tool if you can. If you really must log in to something then follow the checklist above and when you next get access to a known safe computer don't forget to change your passwords!

If you have any feedback regarding this article, or you have a suggestion for a new article, or just want to say thanks for the info then feel free to drop me an email at

Article date: 4th March 2011

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