Live data from Hacker News

Ultrasound Tracking Could Be Used to Deanonymize Tor Users

bleepingcomputer.com

51–60 of 67 posts

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#51
post #20

How is javascript playing ultrasound not seen as an attack on the user? In what world is that ever a sane thing to do?

I can think of plausible use-cases: e.g. wireless data communication with devices that aren't networked.

I've got scuba-diving computers that need special cables to sync with my PC: if they could sync with nothing more than a webpage and speakers, that would be pretty neat.

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#52
post #40

Earlier quoted context omitted.

FWIW, there was a BBC article about always-on audio detector apps. Describing an Android proof-of-concept app: "The battery drain during our experiments was minimal and, using wi-fi, there was no data plan spike." http://www.bbc.com/news/technology-35639549

They don't give much information on what "minimal" battery drain means. I'm skeptical. Keeping an app running in the background and keeping a stream of audio data piped into it to be processed on the CPU is not cheap. Google has a dedicated DSP on phones to do hotword detection (among other things), and IIRC that's not exposed to unprivileged apps. Hell, even iOS needs to be charging to get "hey siri" support (not su…

This example is about people using TOR on a computer, so your phone is more likely to be connected to wifi than the general case.

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#53
post #5

I read about a lot of you security people talking about the difference between a physical switch turning off your wifi vs a software switch, does anything like that apply to this?

A physical switch is for surety and peace of mind, whereas a software switch you have to be careful, because I don't trust my machine's OS to keep the speakers muted, no matter how much the chain of trust has not been compromised, there's always a weak link somewhere. Physical switches or death.

Or death? That is a bit dramatic...

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#54
post #40

Earlier quoted context omitted.

FWIW, there was a BBC article about always-on audio detector apps. Describing an Android proof-of-concept app: "The battery drain during our experiments was minimal and, using wi-fi, there was no data plan spike." http://www.bbc.com/news/technology-35639549

They don't give much information on what "minimal" battery drain means. I'm skeptical. Keeping an app running in the background and keeping a stream of audio data piped into it to be processed on the CPU is not cheap. Google has a dedicated DSP on phones to do hotword detection (among other things), and IIRC that's not exposed to unprivileged apps. Hell, even iOS needs to be charging to get "hey siri" support (not su…

You're right, the article is talking about seems to be talking about sending the audio wholesale, which would be cheaper from a CPU perspective, but sending the data would probably be noticeable both from a data use and battery perspective.

Having said that, quite a few people have their phones connected to wifi at home, which could mitigate these issues due to both less conspicuous data and power usage.

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#55
post #25

Earlier quoted context omitted.

Technically lowpass :)

Ahh but what about sub sonic messages? Slow datarate to be sure but definitely possible. If there's any monkey business going on with my audio, I want it in the range where I can hear it!

Do you mean messages sent over infrasound (less than ~20 Hz)? That would typically not work, because most speakers cannot produce infrasound and most microphones don't pick up frequencies that low

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#56
post #38

Earlier quoted context omitted.

And I'm not sure there is anything stopping a Tap from listening without you knowing.

Any device that is listening all the time can be storing and sending anything you said. How would you know if it's encrypted? There has GOT TO BE a better way. Such as a filter made by independent manufacturers that opens the sound channel only when you say a specific phrase such as "OK Google" and closes it when you press a button or stop speaking. And an indicator would be visible when it's actually listening. The…

How would you know if it's encrypted?

If outbound traffic levels are the same when you're using it as when you're not, it's probably bugging you? Of course a smarter arrangement would reschedule traffic to coincide with use...

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#57
post #41

Earlier quoted context omitted.

TorBrowser has JS on by default I thought.

No. That would be reckless and would compromise Tor Browser Bundle from the outset. By default, the NoScript plugin disallows JS from running globally

> No. That would be reckless ...

Maybe so, but I think the GP is correct. At least, it was true a year or so ago.

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#58
post #5

I read about a lot of you security people talking about the difference between a physical switch turning off your wifi vs a software switch, does anything like that apply to this?

A physical switch is for surety and peace of mind, whereas a software switch you have to be careful, because I don't trust my machine's OS to keep the speakers muted, no matter how much the chain of trust has not been compromised, there's always a weak link somewhere. Physical switches or death.

> A physical switch is for surety and peace of mind

Theoretically, there's no reason to trust a physical switch more than a software switch, unless you've opened the computer and verified that the physical switch breaks all circuits to all wifi radios. The physical switch could merely control software, or it might control one connection to one radio but not others.

Re: Ultrasound Tracking Could Be Used to Deanonymize Tor Users

#60
post #59

Are cheapo mic and speakers even capable of operating at those frequencies?

Absolutely. 20kHz, from an electrical engineering perspective, isn't really a wide bandwidth. You might get some fairly strong distortion but almost always it will still work, unless we're talking about something like a piezo.
Post reply on HN