Your TV can see through walls (2025)

Posted by Curiositry 10 hours ago

Your TV can see through walls (2025)(maurycyz.com)

224 points | 98 comments

numlock86 8 hours ago|

Wait for people to learn about that you can listen in virtually anywhere through fiber-optic cables, as sound waves are enough to redirect the light in the cable to a measurable degree by "bending" the cable itself. Special devices to filter these variances out and transform them back to audio signals are a thing. It's only per line though, as any repeating device will just output a new cleaned up signal again.

Oh well, there have always been ways to snoop on someone like that. Back in the day it was CRTs emitting measurable waves through the neighborhood, with some papers even going as far as restoring the displayed image through a wall. Nowadays it's fiber and WiFi, and those seem to be much easier to work with even. Plus everyone carries a device that is tracked by their mobile provider's cell network. shrug

p_l 43 minutes ago||

Funnily enough, first time I've seen it mentioned was in Ghost in the Shell manga from 1990s, where Major's side business illegally offers military grade optronic touch/etc senses in artificial skin for cyborgs, using measurements of bending fiber optic loops

ClikeX 6 hours ago|||

You can also listen for audio simply by measuring any vibrating surface with a laser. Which goes all the way back to the late 40s, used by the USSR. |

Fun fact, it was invented by Leon Theremin. The inventor of the Theremin.

dghughes 1 hour ago|||

1940s? The LASER device was invented in 1960. The Soviet spies used an infrared light beam.

ClikeX 40 minutes ago||

The point was light being used for audio, not specifically laser as a light source.

hansonkd 26 minutes ago||

You seem to keep responding to multiple people defend your point, but he used 1320 MHz in the thing which is not light.

the words you use matter.

b3lvedere 5 hours ago||||

Yup: https://news.mit.edu/2014/algorithm-recovers-speech-from-vib...

fortran77 1 hour ago||||

You are completely wrong.

Here's what Theremin invented: https://en.wikipedia.org/wiki/The_Thing_(listening_device)

ClikeX 41 minutes ago||

Yes, he invented the technique of monitoring audio through light. How was I wrong there?

bariumbitmap 11 minutes ago||

The Thing uses a radio signal at 330 MHz (or perhaps a second or third harmonic). These radio waves have a wavelength of about a meter, which is about 6 orders of magnitude longer than an optical wavelength. It's a fundamentally different mechanism than laser Doppler vibrometry.

fouc 1 hour ago||||

>The theremin is an electronic musical instrument controlled without physical contact by the performer.

ForHackernews 5 hours ago||||

https://en.wikipedia.org/wiki/The_Thing_(listening_device) is a fun read for people who haven't seen it before

neuronexmachina 35 minutes ago|||

> Back in the day it was CRTs emitting measurable waves through the neighborhood, with some papers even going as far as restoring the displayed image through a wall.

It's been some time since I've thought about Van Eck phreaking: https://en.wikipedia.org/wiki/Van_Eck_phreaking

iamnothere 2 hours ago|||

I don’t get your point. Yes, there’s a lot of eavesdropping techniques available to actors with nation state capabilities (or with a lot of time, money, and expertise). This is another one of them. It’s good to be aware of things like this because it helps you better understand threat modeling for applications that require serious hardening.

There may also be unusual applications of this, like the traffic counting mentioned by another commenter.

(For anyone who needs hardening against things like this, you need a SCIF.)

kurthr 7 hours ago|||

Just toss a doppler laser interferometer on a window, mirror, etc. At least with fiber-optics you need physical access. Single mode (I think that's most of FTTH) is pretty insensitive to vibration and hard to localize so you'd really have to install something.

taneq 3 hours ago|||

In this context, is line of sight with the ability to emit and receive laser radiation at the target not ‘physical access’?

JDups 5 minutes ago||

Not for an exterior window.

andai 6 hours ago|||

Ah, but of course. How could I forget about my trusty pocket doppler laser interferometer!

ben_w 6 hours ago|||

This is a "high school project funded with pocket money" level of DIY, with €25 of parts.

JdeBP 6 hours ago||||

Yours is not built in to your watch? You should go and have words with Q.

aa-jv 5 hours ago||||

Microwave beam-forming says what?

taneq 3 hours ago||

I didn’t hear it say that. I guess I’m not the target. :P

taneq 3 hours ago|||

Included in the next version of Flipper. /s

euroderf 6 hours ago|||

So when AI takes over the world, it will have a convenient tap into every living space of every hoomin. Lovely.

w4der 6 hours ago|||

Fiber optic interrogators are (for now) expensive and bulky, so I don't think commercial modems are capable of that (yet).

ck2 2 hours ago||

trackers are also now becoming near microscopic

they track BUTTERFLIES from Canada to Mexico by attaching tiny trackers with eyelash glue

* https://celltracktech.com/products/ctt-blumorpho

smaller than a tic-tac candy (about two match-heads)

* https://cellular-tracking-technologies.github.io/ctt_documen...

armcat 6 hours ago||

Several years back we actually made use of the principle mentioned in this post, to more systematically count traffic on the roads [1]. In our case we used LTE/4G radio, and we could even estimate the direction of travel, as well as the type of traffic (pedestrian, small vehicles, large vehicles). It was more accurate than Google Maps because it was independent of the moving phone, i.e. it was "sensing the obstacles in the environment".

[1] "Traffic Flow Estimation using LTE Radio Frequency Counters and Machine Learning", https://arxiv.org/abs/2101.09143

swerner 8 hours ago||

As anyone observed who had a TV with just basic analog terrestrial antennas, before cable and satellite dishes - it does make a difference to the signal, when and where you stand and countless pieces of physical comedy in TV shows incorporated that.

reddalo 6 hours ago||

As soon as I've read your comment, I've thought about this Mr. Bean's sketch: https://www.youtube.com/watch?v=4S9-vDow2d0

pmontra 6 hours ago|||

And reflections on other buildings (which usually cannot be compensated for,) wind bending antennas, etc.

taneq 3 hours ago||

Ah, the old ‘stand in a funny pose so the family can watch the show’. Such a classic. :P

1e1a 8 hours ago||

See these for a very low cost (<$10) method for observing WiFi and some LTE spectra:

https://news.ycombinator.com/item?id=49922674

https://espargos.net/espsdr/

doginasuit 1 hour ago||

I thought this article was going to be about putting a webcam on the other side of the wall and streaming through the TV, which somehow had never occurred to me and I want to try it now.

fzeindl 8 hours ago||

Amazing book about similar topics: “Silence on the wire” by Michal Zalewski

https://www.amazon.de/Silence-Wire-Passive-Reconnaissance-In...

6c696e7578 5 hours ago|

Anything in my price range?

fzeindl 3 hours ago||

What is your price range? You could check your local library for borrowing it.

nubinetwork 2 hours ago||

I know this is written to sound scary, but it's been like this since the invention of the radio/telegraph (late 1800s?). You're getting blasted by rf almost continuously, unless you live in a bunker.

Reubachi 1 hour ago||

This is written to sound scary/capatalize on a relatively underdiscussed snooping mechanism.

But it isn't at all like straight UHF/VHF radio intereference spectra analysis or whatever we want to call it.

Wifi, Cell network bands, bluetooth and hard fiber lines are all far more exploitable than "regular" RF . A police squad car equipped with the RF package (which convienetly comes from defense contractors) can grid out your home and hotspot people, devices, etc. This is only possible due to exploits/abusing these standards and cooperation w/ device/tech vendors.

Is this a problem? Eh, not for me where I live. Is it illegal? I am not versed enough to know how procedural/ y the books this is. But it is odd that a passing police vehicle potentially has unmarshalled/warrentless seach running 24/7.

nubinetwork 57 minutes ago||

In order for that to work, they would have to stand on one side of your house, and scan from the other side. If they're already surrounding your house, they might as well just bust in.

fwip 25 minutes ago||

Having two guys with gadgets is a much lower bar than getting a court to approve them busting into your house.

NooneAtAll5 1 hour ago||

"I know this sounds scary, but don't worry - all this spying won't give you cancer!"

reactordev 3 hours ago||

I threw away all TVs in my house after the proliferation of ads on the Home Screen. Sorry, the only value a TV has is displaying images and audio at large sizes. Not getting me to shop. So I decided to get rid of them all and now I use large monitors and projectors. Make TVs dumb again.

iamnothere 1 hour ago||

The article is about radio waves from TV broadcast towers, not the TV in your home.

VCFundedGenYer 2 hours ago||

This makes no sense.

This problem is solved via two ways (or both at once):

- Pihole

- Unplug the TV from ethernet and disable wifi

All my TVs display no ads because they are jailed.

rapnie 1 hour ago|||

> Unplug the TV from ethernet and disable wifi

This likely requires opening the case and physically disabling (hence knowing what you are doing). Or the TV will find other devices to transmit the data. Not an easy measure for everyone.

bethekidyouwant 1 hour ago||

a TV cannot "find" a way onto the internet without your wifi password (don't say insecure wireless networks)

rapnie 1 hour ago||

Tangential. Of both LG [0] and Samsung [1] smart TV's it is known they spy on you any way they can. Does someone know if they do that too for models sold in Europe, which would likely be in violent breach of GDPR?

[0] https://www.youtube.com/watch?v=6IFVTcM28KA (Gamers Nexus findings)

[1] https://www.youtube.com/watch?v=VFx1DyAjxYc (LMGClips summary)

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