Secret US spy program snoops on citizens' smartphones with aeroplanes, claims report

Devices called 'dirtboxes' mimic mobile phone towers to locate mobiles

The shadow of an airplane is seen over fields in Missouri. (Getty)

American law enforcement is reportedly using spy planes equipped with military-grade snooping technology to hoover up information from millions of smartphones in the US.

A report from the Wall Street Journal (£) claims that Cessna aeroplanes equipped with “dirtboxes” are being used to mimic mobile phone towers, helping the US Marshals Service track criminals while recording innocent citizens’ data.

The project began operation in 2007 and is operating from five metropolitan airports in the US. Between them the planes have a flying range covering the majority of the US population, says the WSJ citing “sources familiar with the programme”.

The US Justice Department has neither confirmed nor denied the existence of the program, though the technology being used is similar to known method called stingray.

Both stingray devices and “dirtboxes” use off-the-shelf components to collect mobiles’ International Mobile Subscriber Identity (IMSI), an identifying code unique to each device. They can be used to track individuals’ movements via their mobiles but work indiscriminately, hovering up information from a general area.

A number of different US agencies including the FBI, Drug Enforcement Agency, Secret Service, Army, Navy and Marshals are known to use stingrays, and security experts say that these capabilities have "become, for better or worse, globalised and democratised."