How Uber Drivers Are Helping Detect Cellphone Surveillance

With 'SeaGlass,' researchers are creating city-wide sensor networks that detect secretive police surveillance tools

Photo Illustration: Diana Quach
Jun 02, 2017 at 5:10 PM ET

Despite their widespread use by police across the U.S., stingrays — the colloquial name for IMSI-catchers, the dragnet surveillance devices that track phones and intercept messages — are still fairly difficult to detect. They work by mimicking cellphone towers and causing nearby devices to automatically connect with them, often with the user none-the-wiser.

But researchers at the University of Washington have engineered a new solution called SeaGlass, which uses networks of sensors to detect the ubiquitous but stealthy surveillance tools on a city-wide scale.

The system works by placing hundreds of sensors made from cheap parts that continuously ping nearby cellphone towers, using an attached dummy cellphone as “bait.” The battery-powered devices then use a mobile hotspot to share data and report any anomalies, which are detected by measuring deviations from models of normal cell tower behavior.

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“Up until now the use of IMSI-catchers around the world has been shrouded in mystery, and this lack of concrete information is a barrier to informed public discussion,” said Peter Ney, a University of Washington doctoral student and co-lead author of an upcoming paper about the detection system, in a statement emailed to Vocativ. “Having additional, independent and credible sources of information on cell-site simulators is critical to understanding how — and how responsibly — they are being used.”

The sensor devices can be placed anywhere, but work best when inside a vehicle and driven around the city. For their initial tests, the UW researchers got help from volunteer drivers working for rideshare services like Lyft and Uber, who drove around the streets of Milwaukee, WI and Seattle, WA with the sensors in their trunks. In a two week period, the researchers say 15 ridesharing vehicles picked up dozens of anomalies consistent with patterns normally exhibited by the use of police stingray devices.

SeaGlass isn’t the first solution researchers have created for detecting stingrays, but it’s without a doubt the most comprehensive and built-to-scale. Previously, apps like SnoopSnitch have allowed users to detect anomalous cell tower transmissions in their nearby area using their phone or tablet, but would require the device to be jailbroken or rooted in order to get accurate measurements.

The University of Washington researchers caution that those anomalies don’t always necessarily indicate the use of a stingray. But while confirming their use with total certainty remains an elusive goal, researchers’ ability to detect the infamous devices in slowly improving.

“We did find weird and interesting patterns at certain locations that match what we would expect to see from a cell-site simulator, but that’s as much as we can say from an initial pilot study,” Ian Smith, another one of the paper’s co-lead authors, said in a press statement. “But we think that SeaGlass is a promising technology that — with wider deployment — can be used to help empower citizens and communities to monitor this type of surveillance.”