DOJ reportedly spies on mobile phone owners using fake airplane-mounted cell towers

As outlined by The Wall Street Journal on Thursday, the supposed secret spy program equips small aircraft with a device dubbed a "dirtbox," which pulls data from mobile phones by masquerading as a cell tower. The project aims to identify criminals through their devices, but the wide net also snares cellphones used by the general public.

Purportedly operated by the U.S. Marshals Service's Technical Operations Group, the dirtboxes are manufactured by Digital Receiver Technology, a subsidiary of Boeing, and installed on fixed-wing craft like those built by Cessna. The two-foot-square devices identify themselves as legitimate cell towers with the strong signals, tricking mobile phones into reporting IMSI information.

Privacy safeguards appear to be built in as the dirtboxes parse out devices linked to criminals and "lets go" of phones that are not suspect. Sources, however, suggest data is still gathered prior to release.

These people said the system can gather data and the general locations of tens of thousands of phones in a single flight. In addition, dirtboxes can interrupt calls, while newer versions are capable of jamming signals and scraping rich data like texts and photos.

Since dirtboxes are exploiting the fundamental structure shared by all cellular networks, no level of encryption is able to withstand the noninvasive attack. The DOJ would not confirm or deny the program's existence, but did say that its agencies are in compliance with federal laws. It is unclear how often the planes are sent out, but sources claim the program is operating on a regular basis.