by Gerry Sneeringer

Whether you call them memory sticks, USB keys, or flash drives, there is no denying that these small devices have revolutionized the way in which we copy documents, images, music, and video from one computer to another. A reusable drive capable of holding the contents of four DVDs can be purchased for less than $50. Smaller devices can be purchased for only a few dollars.

Unfortunately, the growing use of these devices has prompted the re-emergence of a computer security issue that has been lying dormant since the demise of the floppy disk — the transmission of computer viruses using human carrier pigeons. There has been a recent increase in the number of viruses that spread by silently jumping onto an inserted memory stick. The virus-on-a-stick is installed in such a way that Windows may automatically launch the virus when the stick is inserted into another computer. When sticks are passed around or a number of them are inserted into the same computer, there is potential for a virus to spread rapidly.

What to do? Keep your USB keys safe from infection and your computer safe from infected keys. If you insert your key into an infected computer, there is very little that you can do to prevent a determined virus from invading it. As long as the key is inserted, it is at the mercy of the host computer. Reduce your risk by plugging your key into the computers of others only when absolutely necessary. Separate keys that you use for personal storage from ones that you use for sharing. Assume that files on your sharing keys might be destroyed; do not store anything on them that cannot be replaced. Naturally, the sharing key should not contain files that you would not want to share with the world.

How do you protect your computer from infected flash drives? The number one answer is the same now as it was with floppies: use an antivirus product that automatically receives updates to combat emerging viruses. Members of the university community can download software like this from the OIT Help Desk (www.helpdesk.umd.edu/virus/software.shtml). In addition, many Internet Service Providers give away antivirus software to their customers.

For additional protection, ensure that your computer does not “auto-run” programs on USB keys when they are inserted after being used elsewhere. Some keys masquerade as CD drives when inserted, so blocking auto-run for programs on CDs is also a good idea. Windows XP users can prevent auto-run by holding the left Shift key while inserting the USB key. Vista users need to turn off the feature from their computer’s Control Panel. Once the key is assigned to a drive, use My Computer to explore the key to ensure that you recognize all of the files stored on it.