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Comment by imron | Hacker News Reader

Let's say you're a journalist meeting with a source.

Let's say a certain three letter agency would like to listen to that conversation in real-time if they could.

Let's say the journalist thinks that by setting his phone to flight mode, the radio is off and he can't be maliciously tracked.

Let's say the three letter agency has various means to connect and listen in on phones in real time if it chooses.

This new smartphone case would then be able to confirm to the journalist that the phone is not sending/receiving radio signals.

Now, that might sound like a far-fetched scenario, but bear in mind that Snowden asked reporters meeting with him to put their phones in his fridge to prevent exactly that scenario from playing out.

It is therefore not surprising that he might play a part in developing a case like this.

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So we assume that an adversary has dropped some malware that can silently enable the radio, activate the microphone, encode the audio stream and transmit it in real-time - and they want to avoid detection by this case.

Well, all they need to do is modify the malware to record the audio to a file and transmit it when the radio is next switched on, perhaps interleaving it with normal radio activity.

As a malware detector, this case is useless.

They would have to know the exact meeting time and would use space on the device, which could be noticed.

This case is not a silver bullet, but it's a useful tool.

Or they could record to file only when the radio is off, and transmit directly without recording when it is on.

Not useless. Just less useful.

It pushes the capacity for your adversary to operate into (slightly) slimmer confines, which is a marginal improvement.

Otherwise, your adversary can behave in an unrestrained manner. No?

I guess. For the kinds of clients who would want this device, this would just be like making it so that you're only a little bit pregnant. You either prevent the eavesdropping or you don't. The only safe tactic is not bring the device anywhere you don't want to be tracked or recorded. Or to technologically prevent it from operating somehow in a way that doesn't rely on verification -- such as taking the battery out, if you can, or putting it in a verified faraday cage that you keep in a soundproof box if you can't. And if you're the kind of person with a life so interesting they need to worry about about phone implants, maybe take battery removability into consideration when you buy the device.

One might also argue that giving a violent prisoner left-handed scissors will slow them down and is therefore a marginal improvement.

I can't argue with that: if I had to choose between the two, I'd rather be stabbed by the non-dominant hand. Obviously not being stabbed at all is a much better choice (when available).

That was my immediate thought, if they have access to your phone at that level recording (voice, packets, gps co-ords) to a file then sending it once it has signal would be trivial. It would provide a misguided level of confidence in their security which could lead to exactly the consequences trying to be avoided.

Got a secret meeting? Don't take your bloody phone.

Of course not taking your phone is a visible data footprint if you're detected in other ways. Secrecy is a pretty hard problem now.

The objective, in this case, is to prevent recording of the proceedings, not keep the very existence of the meeting a secret.

It has been confirmed that some mobile basebands are, in fact, remotely controllable even when a device is apparently off. It isn't a far-fetched scenario.

http://www.seattletimes.com/nation-world/even-if-theyre-off-...

In this case it was a Motorola device on an iDEN network, probably using a Freescale baseband. But it is likely that most major vendors were persuaded to include similar capabilities and that network providers cooperate in providing special signaling to control these capabilities.

That a security measure is not impossible to defeat does not mean it's useless.

This also detects when the GPS is used. If the phone has GPS and cell radio (for reception and transmission) disabled, it's a lot harder for any malware to figure out its location (not impossible -- there is some research about identifying locations in a metro network using an accelerometer alone).

While it's easy to prevent the phone from recording your conversation (just place it somewhere out of earshot, maybe next to a noise source for the duration of the conversation alone), it's much harder to prevent it from learning where you're going (if you're taking it with you).

Baseband processors in all mobiles have direct access to the microphone and it is fairly trivial to access remotely. Comes as standard on all stingray devices available to any and all perverts willing to use it.

Only Samsung devices have been shown to give the baseband processor backdoor access to device storage. Afaik.

The next logical question is why is this case better than putting their phones in the fridge?

Because you can't take the fridge with you on a false trail, place the phone inside at some point before deviating to the true meeting point, and then pull it back out again once the meeting has been completed and sufficient distance has been traveled.

Even some sort of electromagnetic shielding case or bag wouldn't be as convenient (so more likely to be used) or informative.

The introspection/detection part. That's the only part, actually. It doesn't stop the signals by itself.

Yeah. Or have a little metal case with you into which you put your device. Or buy a roll of aluminum foil and just wrap the phone inside it (just spelling this out makes me feel like a conspiracy theory nutter). So many cheap options...

There are fairly cheap little faraday cage forensic bags that LEOs often purchase in bulk. Power off phone, slip phone in, it's not transmitting any more.

Using this thing, you will know that you've been compromised if a transmission occurs. Fridge won't tell you that.

Knowing you are compromised, you could prepare disinformation to throw off, embarrass or otherwise humiliate an adversary.

Wouldn't a faraday cage be effective here? I suppose it doesn't confirm that you are being surveilled, but it would block radio signals.

https://twitter.com/Snowden/status/737769180087353345

In the fridge? Let's hope he knows how far the closest tower is for the journalist's carrier.

My Galaxy Note 4 gets a solid connection on T-Mobile in the fridge, in the oven, in the washer, and in the dryer.

It's in the range of 33ms ping, 45Mbps upload, 24Mbps download in each of those locations.

Why? T-Mobile has a neighborhood tower one short block from home.

The fridge would block the ability of the microphone to pick up sounds, not block the cell tower signal

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