Innovative Attacks Treat Mobile Phones As Sensors

As smartphones become more powerful, technologists have increasingly referred to the devices as pocket-sized computers. Yet less often do the experts consider the implications of a different aspect of the devices workers are carrying around: that of a capable pocket-sized suite of sensors.

Researchers have begun to focus on this facet of mobile phones. Last week, for example, computer scientists at Georgia Tech showed how placing a phone on a desk could allow its accelerometer to detect the vibrations from key presses on a nearby keyboard and pick out words with an accuracy of up to 80 percent.

The research showcases the possibilities in using a smartphone's sensors in innovative ways; while the attack might be more difficult than other methods of keylogging, it could be used for espionage to great effect, says Patrick Traynor, an assistant professor in the School of Computer Science at Georgia Tech.

"The best-case scenario here, if you are an attacker, is if you are going after a very specific person," he says. "I think it is realistic in that case."

People have started adapting to the implications that they are carrying around a capable computer in their pockets, but still have not absorbed the fact that they also are carrying a capable sensor suite as well. Last year, researchers from Rutgers University showed how attackers could use an Android rootkit to listen in on conversations by intercepting calendar events and turning on the microphone during scheduled meetings. A year ago, an Android Trojan known as Tapsnake tracked users movements by using the global positing system (GPS) sensor and sending off data every 15 minutes.

The various sensors means the implications of a smartphone attack are not as easy to predict as for a computer, says Liviu Iftode, a professor in the department of computer science at Rutgers University and one of the authors of rootkit paper.

"What makes a smartphone different from just being a mobile computer is all these extra [sensor] interfaces that are provided on the phone for different purposes," he says. "Once you have access to this larger body of features, the implications of an attack can be much larger and can be more complicated to address."

The most popular sensors that attackers will target will likely be the microphone, GPS sensor, and wireless networking devices. Yet the accelerometer and camera could also be major targets, Iftode says.

The trend toward the consumerization of IT means companies have less control of the security of the devices coming into the network. Requiring that users install some security measures and limit the applications that are downloaded can go a long way to preventing malware infections. Firms with more sensitive requirements could use technology to turn off the sensors in certain locations, says Tom Kellerman, chief technology officer for security firm AirPatrol.

The company, which produces technology to implement security based on location, frequently is used to turn off phone features that leak location. Yet switching off other sensors could be just as important, he says.

"You might want to turn off the accelerometer in the workplace; it has no reason to be on at work," Kellerman says. "There is no reason for Bluetooth to be working in the workplace. Maybe specific capabilities should be toggled down."

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