I hope this is not too off-topic. This morning when I read news it was full of articles quoting Snowden in his most recent interviews. Apparently the UK's GCHQ and the USA's NSA can (1) turn your phone on and off at will (2) turn your mic on and off at will, listening (3) take pics at will, watching etc. all by sending an encrypted text which we will never actually see.

Check me if I'm wrong, but this seems hopelessly conspiracy-theorish when I consider it from a technical perspective.

(1) When my phone is off, what signal exactly are they going to send to wake it up? When my phone is off my battery goes for months with a barely perceptible drain - is the idea that this barely perceptible drain is intentional and being used by the security agencies? Or that they have a special battery in each and every handset ever made which somehow (magically) has never been discovered in any of the thousands of tear-downs that have been done?!

(2) I have tried some of the apps that are out there to work with my phone remotely. Inevitably they work great on the phone that the developer used in his original testing and they work like crap on most other phones. Are we saying that the NSA/GCHQ has developers dedicated to this on every single platform available? And they do it in advance of every single release so it can be part of the ROM? And they do this regardless of what country the handset maker is in?!

(3) And isn't android open source after all? Doesn't that basically completely rule out the possibility of some huge gaping hole like this?! Surely some 13-year-old would have run across it and once it's discovered how can it not be publicized with internet 2.0 the way it is today?!

I've got friends who were already convinced they needed to take their battery out of their phone when having a conversation (like the NSA cares who won the latest football match?!) - this is just going to throw gas on that fire. I'd like some technical responses to this question...

(No need to just quote the articles or tell us how much Snowden knows - I'm interested in the technical side of things as to whether something like this is remotely feasible.)

To make the question more focused: Is it technically possible that someone could turn on your phone remotely when it was completely turned off (but with battery still in)? Is it possible that spyware could be of sufficient quality to be useful (listen/pic and then send somewhere, presumably) and still buried so deeply that nobody was aware of it? So the question is strictly limited to the technical viability - could it theoretically be done?

  • Ah, I didn't realize android was both closed and open source. That would make a difference. However, I would think that at some point every line of code in the android open source collection has been gone over by multiple independent developers - it's not like some unknown software project attracting little notice... Oct 6, 2015 at 15:23
  • 1
    @PeterBowers I think you overestimate the motivation of people looking at open source code.
    – mattm
    Oct 6, 2015 at 16:27

1 Answer 1


Yes, the government can perform nefarious acts on your phone to listen in on what your are doing.

  1. If you phone is truly off, there is no signal you can send to wake it up. But:

    1. You can spoof the phone turning off.
    2. In some older feature phones, turning your phone off was not good enough because some things on the phone stay awake, and the FBI used this to eavesdrop on mobster phones.

    One of the best ways you can ensure your phone is truly off is to remove the battery.

  2. This is something they do to particular people. It's not technically feasible to do this to every possible phone, but the government doesn't have to because any given mobster or other target has a particular phone.

  3. This is why there is a market for undiscovered software exploits. Once you get root access, you can basically rewrite software to do what you want.

In conclusion, this is technically possible. But that doesn't mean you shouldn't buy your friends some tin foil hats as a gag gift.

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