Your TV can see through walls

(maurycyz.com)

87 points | by Curiositry 3 hours ago

12 comments

  • numlock86 1 hour 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

    • kurthr 39 minutes 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.
  • armcat 15 minutes 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 2 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.
  • 1e1a 1 hour 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/

  • fzeindl 2 hours ago
    Amazing book about similar topics: “Silence on the wire” by Michal Zalewski

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

  • ThePumpkinGod 2 hours ago
    So, a bad actor can now know when I'm at my house or not, I'm sure that's fine and won't be problematic
    • gruez 34 minutes ago
      Can't they already do that by snooping on ARP traffic on your home LAN? Failing that, if they can get whatever shitty wifi chipset they're using to enter promiscuous mode, they can also sniff all STAs that are in the vicinity, and with some ML they can probably figure out which MAC belongs to your phone.
    • rightnutwingjob 2 hours ago
      Even having three security cameras around the perimeter of your house can allow quite precise location and activity detection inside the house via their audio steams.

      Those mics can be quite sensitive.

      • ThePumpkinGod 2 hours ago
        I don't have security cameras in my house but that's actually interesting to see how things most people have in their house can (and does?) used to spy on them.
      • motbus3 34 minutes ago
        Yes. But depending who is doing the work they can just see what Bluetooth devices are around each hour of the day too... It sucks that everything we have seems to be usable against us
      • SlightlyLeftPad 38 minutes ago
        Really? They can’t seem to pick up a conversation happening directly in front of them.
    • cowlevel 2 hours ago
      They already knew this from your cell phone not being in airplane mode.
      • ThePumpkinGod 2 hours ago
        If I ever try to hide (which is probably impossible at this time and age), I will probably just break my phone not like I can use it anyways every single act in it sends data to too many places to count.
        • guax 43 minutes ago
          I assume the problem is still tracing and association. So long as there is no direct link between you and the device, there is no saying if that is you or not. So grabbing a used phone via cash transaction from someone and only turning it on and using outside of your usual locations could be enough to have it being "anonymous". Then, using a vpn or other proxy that hides your network can make you very hard to find, so long as you don't associate with your real identity in any substantial form.

          The danger with these technologies is not when they allow to precise track you once your general vicinity is known, that was always possible by putting some goons after you. General mass surveillance that is constantly tagged is the problem, flock, PRISM and the other stuffs.

      • lencastre 2 hours ago
        there is always the risk of the isolated Faraday caged house
  • thopterek 2 hours ago
    Thank you for more paranoia
    • rightnutwingjob 2 hours ago
      π RuView turns commodity WiFi signals into real-time spatial intelligence, vital sign monitoring, and presence detection — all without a single pixel of video.

      https://github.com/ruvnet/RuView

      • inexcf 47 minutes ago
        Just so anyone who reads this knows: This is a well known SCAM repo. The install instructions are incomplete and when you manage to get it running you will realize the data it produces is just random except for pre-recorded simulated data. If you check youtube for it you will find hundreds of completely AI generated Videos with not one of them showing the actual thing working. And all while trying to sell you some hardware.

        https://github.com/deletexiumu/wifi-densepose " SCAM ALERT: Technical audit reveals this project is a non-functional AI-generated facade with fake CSI data, no trained models, and suspected star inflation"

    • neverbeenasked 24 minutes ago
      yeah, now I gotta unplug TV too
  • gbxyz 2 hours ago
    • mrmlz 22 minutes ago
      As made popular in Cryptonomicon!
  • darkwater 1 hour ago
    Now, about the wifi part, why isn't there an Home Assistant extension that detects already room presence magically exploiting all of this??
  • walrus01 2 hours ago
    see also, presence detection of humans via wifi signals: https://arxiv.org/html/2308.06773v2
  • jasperrhodes 1 hour ago
    [dead]