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Verbatim from the interview between Brian Williams and Edward Snowden last night:

Snowden: Any intelligence service in the world that has significant funding and a real technological research team can own that phone [refering to Williams' iPhone] as soon as it connects to a network; it can be theirs.

Williams: Can anyone turn it on remotely if it's off?

Snowden: They can absolutely turn it on with the power turned off on the device.

I concede Snowden's first point, fine. But the last? Does Snowden's last claim, that a powered off mobile device can be remotely turned, have any merit? It seems highly improbable and seemingly impossible.

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    I guess it depends on what off means... We turn off a device, but, it may still has a battery running so does that mean it's off? We can turn off computers "on" via network messages so I don't see why not. – Dave May 30 '14 at 9:35
  • @DaveRook off as in powered off, completely. Inert. – njboot May 30 '14 at 11:22
  • I don't know how this question "is not about computer hardware or software." Perhaps specificity. I thought this SE site was the best place to ask versus stack overflow. Anyone, feel free to edit the OP. Thanks. – njboot May 30 '14 at 11:24
  • I suppose if you use the WOL(wake on lan) feature of a computer, you could say the computer is powered off and you are turning it on, or you could say it is not powered off, the power supply is still giving some power to the motherboard and network card (even USB sometimes, as there's the 5VSB wire on the power supply that goes to usb),and it's plugged into the wall with power going to it.So in a sense ur computer isn't powered off-unless you switched it off at the mains.And then a computer can't be 'woken up'.Unless it was connected to a UPS but then it wouldn't completely be off cos of 5VSB – barlop May 30 '14 at 12:27
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There are lights-off management systems in high end servers from 9 years ago. Those systems "keep a flame burning" and when an event happened they woke up the whole system. Now, events that are software generated, such as a button being tapped or some such, could ping one of these lights-out devices.

Are those backdoors built in for use by wireless contact? I don't know. It is technically feasible, it just means a bit more power drain when totally powered off. Is it universally true? Not unless there is something that breaks the rules.

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How do you know your phone is REALLY OFF, without removing the battery altogether ?

Everything on the phone is software controlled. And that includes the on/off button.

With low-level software control, which NSA and other agencies can obtain via hacking or backdoors as Snowden claims, it is completely feasible (even EASY) to make the phone appear to be OFF to the owner, while still keeping a connection with the agency.

The possibilities are endless: Just use the phones microphone to permanently "bug" the owner. Use the GPS to track where he is. Use the camera (in case the phone isn't in his pocket) to take photos of his surroundings.

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This is very much feasible. Usually all the high end devices maintain a small "battery" other than the main one which you normally see. On paper, its purpose is to maintain things like time. That is why when you turn off your device for a day and turn it back on, it has the right time since the clock was very much "on" and was being powered by the smaller invisible battery (usually a bunch of capacitors but it might have evolved into something more sophisticated).

Most (all?) of the Apple and Google devices don't even allow removing the main battery so they have quite higher power at their disposal to power on/off components in a device.

These batteries can be used to power certain signalling components easily which an average human would be totally oblivious to.

  • Wouldn't the battery quickly drain (we're talking about a few days or weeks), if the wireless device is kept active and scanning for a signal? Unlike a timekeeper which would take years to drain even a small battery, a wireless device would be a huge drain. We don't see phones or devices that drain batteries surprisingly quickly when turned off. – ADTC May 30 '14 at 9:27
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    Agreed but this doesn't have to be a fully wireless component. I guess it can just be a simple ping service which may only turn itself periodically. May be something even simpler, low power consuming component. – Aditya Patawari May 30 '14 at 9:31

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