Assisted-GPS a boon for surveillance

By Richard Chirgwin

To save time, battery life and processor cycles, smartphones don’t rely
on “pure” GPS to fix their locations – they get help from location data
in the mobile network. Research presented at Black Hat in Las Vegas last
week cautions users that this represents a serious security vulnerability.

Under A-GPS (Assisted-GPS) schemes, the network can send current
satellite location and time to the receiver, letting it acquire the
signals more quickly; or the device can provide its GPS signal data to a
server in the network for faster processing. Either way, the technology
depends on the handset asking the network for help - and when that
happens, location data is exchanged over the network.

The problems, according to University of Luxemboug researcher
Ralf-Philipp Weinmann, are that requests for help are sent in the clear
and are apparently easy to hijack.

For example, if an attacker had access to a WiFi network the phone
connected to, its assistance request could be captured, and redirected
to the attacker’s server. The attacker would now know where the phone
is, and worse, that redirection would stay in place wherever the phone
went in the future.

According to Technology Review, Weinmann described the attack as “rather
nasty” since “if you turn it on just once and connect to that one
network, you can be tracked any time you try to do a GPS lock”.

Because the processing is often handed off to the device’s main
processor, Weinmann says, it could also act as a gateway for other
attacks, from crashing the target device to planting malware. ®

http://www.theregister.co.uk/2012/07/31/a_gps_hijack/