National Security Agency leaker Edward Snowden told the world last month that the agency can eavesdrop through the microphones of cellphones even when they’re switched off — a claim experts have now confirmed.

According to a team of security researchers cited in a Mirror report, a hack for such surveillance lies within Apple’s iPhone software, which is capable of “playing dead” while it’s still turned on.

Los Angeles hardware engineer Eric McDonald explains that though an iPhone appears to be shutting down when switched off, it is actually entering a low-power mode that leaves essential communication chips still functional.

In this state, the handset can still receive commands – like being told to turn on its microphone.

“The screen would look black and nothing would happen if you pressed buttons but it’s conceivable that the baseband [the cellular function] is still on, or turns on periodically,” McDonald said. “And it would be very difficult to know whether the phone has been compromised.”

“An ‘implant’ is when the NSA intercepts your phone and installs hardware or software on it,” security consultant Robert David Graham wrote in his Errata Security blog.

According to Graham, getting the implant into the phone in the first place is “difficult,” but once there, the agency can usurp complete control of the device. Implants can be installed via a phone’s Internet connection, cellular network, or physical interception.

“Once the NSA installs an implant, then of course they can remotely ‘power on’ your phone, because it’s not really powered off — even when you think it is.”



American and British law enforcement and intelligence services have used mobile phones to surveil targets for years. A technique discovered in 2006 called “roving bug” also allowed spies to remotely switch on cellphone mics, and locate users within a few yards.

According to experts, an iPhone must be put into “DFU” mode to completely shut down all operations.

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