Interceptors look to a typical phone like an ordinary tower. Once the phone connects with the interceptor, a variety of “over-the-air” attacks become possible, from eavesdropping on calls and texts to pushing spyware to the device.
“Interceptor use in the U.S. is much higher than people had anticipated,” [ESD America CEO Les] Goldsmith says. “One of our customers took a road trip from Florida to North Carolina and he found 8 different interceptors on that trip. We even found one [in the vicinity of] South Point Casino in Las Vegas.”
Who is running these interceptors and what are they doing with the calls? Goldsmith says we can’t be sure, but he has his suspicions.
“What we find suspicious is that a lot of these interceptors are right on top of U.S. military bases. So we begin to wonder – are some of them U.S. government interceptors? Or are some of them Chinese interceptors?” says Goldsmith. “Whose interceptor is it? Who are they, that's listening to calls around military bases? Is it just the U.S. military, or are they foreign governments doing it? The point is: we don't really know whose they are.”
Interceptors vary widely in expense and sophistication – but in a nutshell, they are radio-equipped computers with software that can use arcane cellular network protocols and defeat the onboard encryption. Whether your phone uses Android or iOS, it also has a second operating system that runs on a part of the phone called a baseband processor. The baseband processor functions as a communications middleman between the phone’s main O.S. and the cell towers. And because chip manufacturers jealously guard details about the baseband O.S., it has been too challenging a target for garden-variety hackers.
In the wake of Edward Snowden and the NSA scandal, one might assume that these 'interceptor' towers might be the work of a government agency. However, some experts have said an agency securing the land and building these towers would be an awful lot of effort considering they're capable of remotely tapping phones with or without a court order.
The possibility remains that these devices could have been installed by a foreign intelligence agency or organized crime to install spyware on mobile devices, eavesdrop on conversations thought to be secure or surreptitiously obtain passwords.
So far, the interceptors have been discovered in south Florida, New York, North Carolina, Illinois, Ohio, Texas, Washington state, New Mexico, Colorado and Nevada and Arizona. Goldsmith and others expect that more will crop us as well.