Wi-Fi spoofing sends Jesus phone disciples off the true path

Punters using Wi-Fi based positioning systems on their mobile devices would do well to look before they leap. Security vulnerabilities have discovered location spoofing flaws in the Skyhook positioning system that might be used to lead users astray.

Devices using Skyhook's Wi-Fi Positioning System (WPS), including the iPod touch, iPhone, Nokia mobile phones (running the WPS applet), and PCs (using Skyhook's Loki plugin) are potentially vulnerable to spoofing.

The technology cross references Wi-Fi access points visible at a particular location with entries in a database to work out its position. This position is then used to pinpoint a device's location on a map, from which users can navigate their way around to nearby restaurants or hotels (for example).

Skyhook runs the database that contains data on access points around the world, collected by the firm and supplemented by its users. When a client device wants to find its position it sends data on nearby access points to Skyhook servers, which respond with the location of a client.

However, security researchers at the Department of Computer Science at ETH Zurich University have established that the Skyhook system can be foiled by jamming signals from nearby access points before impersonating an access point at a remote location.

"These two actions create the illusion for localised devices that they are located at positions different from their actual physical positions. Skyhook's WPS system does not rely on fresh and/or authenticated access point signals - it simply requires a device to report Media Access Control (MAC) addresses of the access points that it detects which are compared to signal characteristics recorded before," the researchers explain.

"Since rogue access points can forge their MAC addresses, access point impersonation can be easily done in WPS. Equally, since WLAN signals are easy to jam, signals from legitimate access points can be easily eliminated, thus enabling location spoofing attacks".

The team used an Asus eeePC configured to impersonate access points and software radios to jam legitimate networks.

The researchers hope the work will help to demonstrate the limitations of existing Wi-Fi-based location systems, from other providers as well as Skyhook. Their research is technically interesting, though it's difficult to imagine to what purpose, other than straightforward mischief, attacks based on the approach might be carried out.

The Swiss team's paper on the attacks can be found here. ®