Got a secure Wi-Fi connection? Good for you. But your neighbors may not be so lucky.

According to an October 2006 survey by the Wi-Fi Alliance, three out of 10 home networks are insecure. More surprisingly, one out of four business Wi-Fi networks is totally open, according to a May 2006 survey by RSA.

That same RSA survey found that 20 percent to 30 percent of access points in major cities throughout the world use the user name and password supplied by their router manufacturer, allowing knowledgeable "war drivers" to log in to the device and change its security settings.

Aside from sucking up bandwidth, war drivers can use your connection to send spam, download porn, and snoop around your shared folders.

Using an open Wi-Fi network yourself isn't exactly safe, either. You could log on to an open network in an airport or other public space and end up on an “evil twin,” a Wi-Fi network set up to mimic a legit one but operated by some creep with a laptop and a mobile access point, notes Paul Henry, vice president at Secure Computing. The crooks could then sniff your data, grab passwords and other sensitive information, and gain access to your corporate network or steal your identity.

If your home net isn't already locked down, now's the time. And if you must access open Wi-Fi nets, use end-to-end encryption for the sensitive stuff.

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