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The US Marshals are scanning millions of American phones with fly-by cell towers

The US Marshals are scanning millions of American phones with fly-by cell towers

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Federal agencies have a new way to find people. According to a new report from The Wall Street Journal, the US Marshals service has been scooping up Americans' cell phone information by planting fake cell tower devices on board small airplanes. The device, known as an IMSI catcher, sorts through the collected data in search of a specific target's unique ID, pointing the Marshals to his exact location. The program has been running since 2007, and according to the Journal, agents get a court order for each search, but it is still unclear whether the orders specify the alarming means by which the resulting search is conducted.

The marshals use fake cell towers onboard small airplanes

The attack plays of a basic vulnerability of cell phones: they're designed to connect to the closest available signal, regardless of how trustworthy it is. For anyone subject to one of the fly-by missions, that signal is coming from an IMSI-catcher box on board a Marshal-piloted Cessna. The box can jam a phone's signal or even retrieve specific text or photo files from the phone. The US Marshal missions seem to have focused on location, triangulating suspects to within three meters by using taking signals from various positions.

IMSI catchers or "Stingrays" have been a controversial tactic for years, and their use is often concealed by law enforcement, but this is the first indication of IMSI catchers being used on a mass scale by a federal agency, and the first time we've seen the devices used from on-board a plane. It's also notable for how broadly the devices are being employed. Following a single suspect would mean picking up signals from even tens of thousands of phones, which means it's likely that millions of Americans have been affected during the seven years the program has been operational.