NPR: Beware of 'Free Public WiFi'

Anyone who has used a laptop or iPhone with wireless Internet enabled in public has seen it before: the ubiquitous network "Free Public WiFi" that seems to pop up wherever mobile users congregate. But according to a report from NPR's All Things Considered, tapping into that network could give hackers an opening into your system.

The network, which has spread throughout the United States over the past five years, doesn't actually let users connect to the Web, the result of a bug in an older version of Windows XP that Microsoft has since addressed.

When a computer running the outdated operating system can't find any of it's "favorite" WiFi networks, it creates an "ad hoc" network with the same name as the last WiFi network it connected to. In actuality, users connecting to that network are connecting directly to the computer that created it.

The networks remain because many users haven't updated their computers, allowing it to spread across the country in a manner similar to a virus. According to Wireless security expert Joshua Wright, it's not the only zombie network out there, either. Others go by the names such as "linksys," "hpsetup," "tmobile," or "default."

Connecting to one of the zombie networks can potentially expose your data by giving hackers a direct line into your system. That's why you should avoid connecting to any wireless network unless you're confident in its origins; these days that increasingly means only accessing networks that require a password, key or some other kind of validation.