As Thanksgiving approaches, perhaps you dread having your turkey with a side of the latest conspiracy theory served up by that uncle (there’s always one) who is convinced the government is spying in from helicopters overhead. This year, though, that relative has some evidence on his side. He’s wrong about the helicopters, as far as we know, but a new report finds that law enforcement agencies actually are using aircraft to scoop up Americans’ mobile phone calls from the skies.

The Wall Street Journal uncovered the program and published their findings this week. The program, managed by the U.S. Marshals Service under the auspices of the Justice Department, uses a high-tech trick to collect cell phone data far and wide, before zeroing in on actual suspect behavior.

Here’s how it works: the Marshals have small aircraft, usually Cessnas, based at a handful of airports around the country. Those planes have devices on board — called “dirtboxes” — that basically fool phones down on the ground into thinking they’re cell towers. A dirtbox is kind of like the electronic version of a duck lure: it’s a fake that can convince phones that it’s the real thing.

By design, as the WSJ explains, mobile phones automatically connect through the cell tower with the strongest available signal as their users move around. But if a plane with a dirtbox is circling overhead, it can convince the phone that it has the closest, strongest signal. That means any phone in range to detect its signal will be sending its unique identifying information to the plane, and not to the best available cell tower.

The theory is that law enforcement agencies can use the technology to zero in on the locations of criminal suspects under active investigation — a specific cell phone identified by a dirtbox can be located to within ten feet. That would tell you not only what building your bad guy is in, but also what room.

In reality, though, the devices are not just magically zeroing on criminal users. Instead, they’re a massive net collecting all signals in the area, after which it sorts through them to find the ones it actually wants and then, as the WSJ says, “‘lets go’ of the non-suspect phones.” The mechanism is less like bringing a magnet to look for a needle in a haystack, and more like bringing a magnet to look for a needle in a needle factory.

The dirtboxes don’t just attract and capture information, either; they can also (unintentionally) interrupt calls or (intentionally) jam signals and retrieve data — like texts and pictures — from a targeted phone.

The WSJ reports that law enforcement has “tried to minimize the potential for harm, including modifying the software to ensure the fake tower doesn’t interrupt anyone calling 911 for emergency help.”

Experts in the field told the WSJ that the U.S. military and intelligence communities use similar devices overseas, to locate terrorist suspects. They also said that in this country, the program has been effective in tracking down alleged drug dealers and murderers. However, they declined to tell the WSJ in which cases the dirtbox tech was instrumental to catching a suspect.

In terms of a “collect it all first, sort it out later” attitude, the air surveillance program is similar to the NSA’s now infamous collection of nationwide records outlining who called whom, when, and for how long. However, in terms of execution, it’s more invasive — up there with NSA programs that have tampered with the electronics or various software that consumers use.

Without actually admitting it exists, a Justice Department official defended the practice to the WSJ after their first report ran.

The official insisted to the WSJ that the DoJ does not maintain a database of the general public’s phone information, and that the technology is used “only in furtherance of ordinary law enforcement operations, such as the apprehension of wanted individuals, and not to conduct domestic surveillance or intelligence-gathering.” The official added that it would be “utterly false” to mix up the DoJ’s skynet program with the NSA’s bulk records database.

However, the WSJ points out, the Marshals do seem to have the capability. The Boeing subsidiary that makes the devices has said in a regulatory filing that some of their machines do have the ability to store information for later cross-referencing, and someone familiar with the tech told the WSJ that when these tools are used overseas, they store data.

With or without data storage, however, the process is likely to increase tensions between the tech community and intelligence agencies. The two sides have been in conflict over issues of surveillance and law enforcement requests since the NSA’s data collection gained widespread public attention in 2013.

Americans’ Cellphones Targeted in Secret U.S. Spy Program [Wall Street Journal]
U.S. Defends Marshals in Wake of Secret Cellphone Spying Report [Wall Street Journal]

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