The Risks of Using Public Computers


Most public computers that I have scanned in my travels are infested with spyware, viruses and/or trojans (malware). It is hard enough to keep a Windows computer clean of viruses if you are the only one using the computer. It is extremely difficult to keep a computer clean if hundreds or even thousands of people are using it.

These are some common activities that people do that can get a Windows computer infected with malware:

  • Opening email attachments, even ones sent by friends
  • Browsing the Web with Internet Explorer (especially non-XP/SP2 version of Windows)
  • Using programs like Kazaa, Limewire, and Bearshare to share files online
  • Running the computer under the "admin" account
  • Running the computer without anti-virus software (surprisingly common)
  • Surfing to shady areas of the Web such as porn, gambling, filesharing, etc.
  • Attaching a USB thumb drive, external hard drive, or other storage device to the computer that may have picked up malware from another computer

Here are some signs that a Windows computer may possibly be infected with spyware/malware:

  • Many popup windows while browsing, even when on sites that don't normally have popups
  • Popup windows that contain advertising even when you are not browsing
  • Unknown toolbars on Internet Explorer
  • Unknown "helper" applications, like weather helpers, cute cursors, search boxes on the desktop
  • A browser that shows an unfamiliar homepage that keeps returning even after you set a different homepage

One way to get a better idea about whether or not a computer may be unsafe is to download a free trial of the Ewido scanner and scan the computer with it. Even if other anti-virus programs say the computer is clean, Ewido will often find additional malware. Ewido is specifically designed to find trojans — programs that pretend to be ok, but secretly contain malicious code. Regular anti-virus programs do not always do a good job of finding trojans.

If Ewido finds trojans, do not use the computer for any kind of secure transactions. Once a computer has certain kinds of malware it is not safe until you reinstall the operating system from scratch.

One effective way to completely bypass an infected Windows hard drive is to use a Linux live CD. With a live CD, the entire operating system runs from the CD in the computer's memory. Since the operating system is loaded from a CD-R it cannot be written to, so you know that you have a clean operating system on every boot. Also, Linux is much more secure than Windows and the risk of viruses is so low in Linux that it is not necessary to use any kind of anti-virus software with it.