Also referred to as “dirtboxes,” the two-foot-square devices operate similarly to the cell towers used by major telecommunications firms.
Also referred to as “dirtboxes,” the two-foot-square devices operate similarly to the cell towers used by major telecommunications firms.

To locate criminal suspects, the U.S. Department of Justice is using small devices attached to airplanes that gather data on thousands of mobile phones, including those used by innocent Americans, the Wall Street Journal reported on Thursday, citing individuals familiar with the operations.

Also referred to as “dirtboxes,” the two-foot-square devices operate similarly to the cell towers used by major telecommunications firms, and can pull in unique registration information from as many as tens of thousands mobile phones in a single flight, according to the report.

“Given the secretive nature of these devices, I can only assume that they are collecting IMSIs (International Mobile Subscriber Identities) coupled with the latitude and longitude of that handset,” Darren Hayes, assistant professor and director of cybersecurity at Pace University's Seidenberg School of Computer Science and Information Systems, told SCMagazine.com in a Friday email correspondence.

The operations involve the use of Cessna aircrafts flying from as few as five metropolitan-area airports, with the range of flight covering the majority of the U.S. population, the report indicates, adding that the program – run by the U.S. Marshals Service – became fully functional around 2007.

People familiar with the operations would not disclose to the Wall Street Journal the frequency or duration of the flights, instead stating that they take place on a regular basis, according to the report, which adds that a Justice Department official neither confirmed nor denied that such a program exists.

Mobile phones typically connect to the strongest cell tower in an area, and the devices used in the program identify as having the strongest signal – although it does not – and forces phones to connect, the report indicates. The devices will mark phones linked to individuals under investigation by the government and “lets go” of others, the report adds.

“The government's use of powerful airborne surveillance equipment that sweeps up thousands of innocent bystanders' cell phone information will result in wholesale violations of our constitutional rights to privacy,” according to a statement by Nathan Freed Wessler, staff attorney with the ACLU Speech, Privacy, and Technology Project, emailed to SCMagazine.com on Friday.

“It is outrageous that this large-scale surveillance of Americans has been taking place in secret,” Wessler said. “These devices pose a serious threat to the Fourth Amendment, and at a minimum there must be robust judicial oversight, full transparency, and strict limits on use.”

Hayes said he finds the program to be far less intrusive than some NSA activities highlighted by Edward Snowden.

“I am not surprised that the ACLU and other civil liberties take issue with the nature and scope of these cell phone user captures,” Hayes said. “It's more that I do not see an issue with this because there is no sensitive content being captured and law enforcement will need to follow up with a warrant to conduct a search only if a judge deems it necessary.”

Hayes went on to add, “Ultimately, the FBI and similar agencies have no inclination or even the resources to analyze the general public's communications and are only interested in finding criminal suspects.”

Another problem is that the device has the potential to interrupt phone calls, the report indicates, citing an individual familiar with the matter who said that authorities have taken measures to prevent the issue from affecting someone dialing, for example, emergency services.