"You connect to one of these networks at your own peril," says Corey O'Donnell, vice president of marketing at Authentium. "And you would have no way of tracking down how you were attacked, because you would have thought you were at an ordinary hot spot connection. Enterprises are also at risk, because if someone uses a corporate laptop to connect to one of these networks and gets infected, when he plugs back in to the enterprise network, the whole network is put at risk."

How to protect yourself in Windows XP

Protecting yourself against these kinds of attacks is quite easy: Never connect to an ad hoc network unless someone you know has set one up and specifically asks you to connect. So no matter where you are, if you see an ad hoc network, don't connect, no matter the name of the network.

Be aware that someone can name an ad hoc network anything they want, so they can even duplicate the name of a legitimate network. For example, if you're at an airport, and the name of the airport's free hot spot is AirNet, someone can set up an ad hoc network with that exact same name. You'd see two networks called AirNet, one being the legitimate one and the other being the scam ad hoc network.

In Windows XP, it's easy to differentiate between an ad hoc network and a normal Wi-Fi network (Microsoft calls connecting to a hot spot or access point being in "infrastructure mode"). In Windows XP, in order to connect to a wireless network, you click the wireless network icon in the system tray, and the "Choose a wireless network" connection screen appears. You'll see a list of all nearby wireless networks.