With the right equipment, people can hijack your cellphone, listen to your calls and read your texts, alarming privacy rights advocates and tech experts alike, says NPR. Law enforcement agencies do it, but they have been restricted by the FBI from telling us about it. Beyond the police, the listeners could be the U.S. government, corporate spies or even foreign intelligence agencies. It’s done with devices known as IMSI catchers or by a brand name like Stingray. They used to be expensive, bulky and hard to purchase. Now they can be bought online for $1,800 and can be as small as a briefcase.
“Today, a tech-savvy criminal or hobbyist can even build one using off-the-shelf equipment,” says Stephanie Pell, a cyberethics fellow at the Army Cyber Institute at West Point. IMSI catchers trick cellphones into thinking they’re connected, as normal, to a network like Verizon or AT&T. But the devices hijack the phone’s signal, and in some cases, intercept the contents of calls and texts. The IMSI catchers take advantage of a vulnerability built into the system. Phones using new technology can authenticate cell towers, but phones on older systems cannot tell between real and fake towers. NPR says, “There’s an arms race on between the technology used to intercept cellphone calls and the technology used to detect that technology.”