No Such Thing As Free Public WiFiNo Such Thing As Free Public WiFi

A recent feature on National Public Radio reminded me of the old Windows XP bug with the "Free Public Wi-Fi" viral networking entry and how it has plagued travelers with Windows PCs for a decade. The problem is declining as Windows XP does, but there's a simple fix for XP to get rid of it once and for all.Just about every PC user has seen the infamous "Free Public WiFi" (FPWF) network in their choices while traveling to one place or another. If you've ever tried to connect to it, though, it just doesn't work. That's because it really is just another traveler's PC, configured as an ad-hoc network. Every time an XP system connects to an ad-hoc network, it remembers the name of the network and will broadcast it later at some other location. This will tempt other people to tell their PC to connect to that XP system. In essence, this "infects" each system into announcing the FPWF name.

Is there any danger in connecting to FPWF? In most cases, the system that you are connecting to is just a confused XP system that also tried to connect to the "Free Public WiFi" access point at some point in the past. When you connect, the hapless victim won't be able to offer any Internet access so your connection "just won't work." The larger danger, though, is that an attacker could set up their own access point with that name; in some cases the PC may try to connect to it automatically. Then the attacker has an easy way to see and/or modify traffic from your PC. So in the right hands, this minor annoyance can turn into a major security hole.

The simple way to ensure that you never try to connect to FPWF is by disabling ad-hoc networks. You can do it with just a few mouse clicks. But remember, the same kind of fake-out can happen when you connect to any unknown and untrusted public WiFi network. Any traffic that isn't going through a VPN or other encrypted connection could easily be stolen. Think carefully the next time you decide to grab Internet access off that "linksys" router near the public park.