Detecting Screen Content via Remote Acoustic Side Channels

https://www.cs.tau.ac.il/~tromer/synesthesia/

by nfrankel • 8 years ago

52 24 8 years ago

cs.tau.ac.il

eb0la• 8 years ago

It reminds me Tempest (https://en.m.wikipedia.org/wiki/Tempest_(codename) ).

This time they are exploiting information leak that goes to unshielded speakers and can be recorded and replayed easily.

Very clever.

John_KZ2• 8 years ago

Although this method can be used for de-anonymization and fingerprinting, you can't fully reconstruct the screen contents from such a low bandwidth signal.

If your private spaces are bugged with microphones or cameras (ie most mobile devices, home audio "assistants", smart TVs, untrusted software etc) expect the owner of the sensor to do the best in their abilities to spy on you.

Ultrasonic ad fingerprinting is another interesting way your home spies can communicate with each other.[1]

[1] https://arstechnica.com/tech-policy/2015/11/beware-of-ads-th...

demomode• 8 years ago

IIRC this is what "Tempest for Eliza" was for CRTs

http://www.erikyyy.de/tempest/

jwilk2• 8 years ago

It doesn't have to be CRT. LCD screen connected via VGA works too.

WillKirkby• 8 years ago

I'm reminded of this DEF CON talk from 4 years ago detailing a similar technique: https://www.youtube.com/watch?v=5N1C3WB8c0o

chupasaurus2• 8 years ago

I enjoy that nobody knows what the Van Eck phreaking[0] is. It works, but to get a good picture the gear is quite large to carry unnoticed.

[0]https://en.wikipedia.org/wiki/Van_Eck_phreaking

onion2k2• 8 years ago

Anyone who's read Cryptonomicon knows what Van Eck phreaking is, and anyone who hasn't read it probably isn't worth talking to. :)

godelmachine2• 8 years ago

Is it really that good? I have been putting that and Permutation City off for quite some time now. Needless to day, I am quite a fan of Neal Stephenson.

52-6F-62• 8 years ago

Cheeky. How about those only partway through? Have pity on the mortals, alright?

John_KZ2• 8 years ago

I assume it's not mentioned because everyone knows it. It's very old news.

godelmachine2• 8 years ago

Steve Jobs started his career doing that with Blue Box.

jwilk2• 8 years ago

But it is mentioned in the article (Q7).

opencl• 8 years ago

The gear is actually very very simple.

eckbox.sourceforge.net/hardware.html

chupasaurus2• 8 years ago

For CRT - yes, but to get a picture from a smartphone's screen the gear would be massive. Saw one used by russian FSS (former name is KGB) on a security audit of some special place.

rocqua• 8 years ago

We assume that the attacker knows the content displayed on the attacked monitor, except for the textual letters. This assumption holds in many cases, for example, when the victim is filling a form on a known website. We also assume that the font is monospace and sufficiently large. The requisite size of the text depends on the granularity of the leak, which changes among different monitors. Another assumption is, again, that the screen is in portrait layout.

They go on to state that in their proof of concept they had 3-6 letter word in black against a white background. They recorded audio for 5 seconds, and the letters were 175 px wide using a monospace font.

Note that they do mention they expect that any background could work, as long as it is fixed and you can train your model on that background.

My point being, this is far from a practical way to read what is on screen.

jcelerier• 8 years ago

yeah but I can't wait until browsers implement random background color change at 60hz for every https website because of "security"

ggggtez• 8 years ago

I think it's better to treat it as a proof of concept attack. It's more just to say: hey this type of thing is possible, maybe with better equipment and more research.

ttul• 8 years ago

Basically, with enough money (read: NSA), you can read anyone’s monitor.

DoctorOetker2• 8 years ago

I've noticed this a few years ago, after reading some psychophysics papers, I was generating some pattern images based on what I read, when my monitor started emitting tunes (not by radio emissions), I suspect piezo effect in some capacitor. I instantly realized my monitor could be intercepted accoustically...

DoctorOetker2• 8 years ago

In my case the monitor was an 1080p LCD panel without speakers...

userbinator• 8 years ago

In a less paranoic way, there's this related item: https://news.ycombinator.com/item?id=8862689

...which evolved from https://news.ycombinator.com/item?id=8856829

Detecting Screen Content via Remote Acoustic Side Channels

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