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
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.)
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.
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".
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.
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.
I haven't had a television for 15 years. My life is far better off for it.
I grew up in a family that watched a lot of tv, so Im not ignorant of it. Going to watch a movie is more special, im more likely to read, I go on walks usually multiple times a day in my downtime instead of sitting on a couch.
But this relies on Hue. I would like something at HA level directly, aka a zero-effort solution if you already run a zigbee swarm either directly controlled by HA or via zigbee2mqtt
Bad actors, and any WiFi capable hardware in your house. There's an official spec for it[1], and some routers already have the option built in. I remember seeing papers about this over 10 years ago, someone at MIT did it for a paper.
Philips Hue also has it built in to their newer lights, where they measure the Zigbee signals. They call it MotionAware[2]. Basically anything with an antenna and a bit of compute is able to do this now.
> So, a bad actor can now know when I'm at my house or not.
A bad actor who wants to act on that information can just wait near your house on a workday morning and watch you leave, likely not to return for the better part of the day. No techno-voodoo required.
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.
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.
Phones and smart TVs, probably other appliances. My SO used to be surprised to receive ads about stuff we talked about minutes before. I finally looked at her phone, disabled a bunch of things in the stock Android settings, those timely ads went away. I didn't even have to install Blockada, uBO for FF (and uMatrix and other addons) like I do on my devices.
I feel like by disabling ads in most devices, I'm also taking away the best source of information on what bad actors (here ad companies) managed to exfiltrate about me.
If there only was a way to sell ad space about myself and learn from it what others know.
Most companies don't allow you to turn off data collection easily. What they do allow is turning off the response to that data (displaying relevant ads).
I mailed her a summary for future reference. It's quite detailed but it was not in English and the phone was not in English too. So forgive me but I asked Claude to translate it and guess the right menu and option names for an English Android. It should be enough to give you the idea of what I did. It was a Samsung phone, not a S series.
Here it is:
---
Tapping <first name last name> at the top of Settings opens the Samsung account notice, and the Terms of Service show as not accepted. I'm leaving them unaccepted and not continuing.
1. Security and privacy
Controls and alerts: left Microphone access on, because permissions will be set individually per app.
More privacy settings:
Send diagnostic data
Set to Off
Samsung
Improve personalized ads based on data from this phone: you have to go to the Samsung account settings.
Receive news and special offers on this phone: same
Customization Service for your phone: same
Going to Accounts and backup > Samsung Cloud > Data backed up: there is no data being backed up to Samsung.
Going to Samsung Cloud shows that Bluetooth, Calendar, Contacts and Wi-Fi are synced.
Google
Google personalization service: set to Off
Permission manager:
Switched to Ask every time:
- Chrome
- Maps
- Meet
- Facebook
- Google
- Messages
- Speech Recognition & Synthesis from Google
- Samsung Keyboard
- TikTok
Still set to "Allowed only while in use": Camera and WhatsApp
Activity controls
Web & App Activity: turned off, but I did not delete the history
Timeline (Location History): was already off since January 1, 2025
YouTube History: left on
Personalized ads:
- My Ad Center is turned off
- Partner ads settings, Visit My Ad Center, Ads you can control, Get started,
Cancel
Everything is disabled, as expected after turning off the Google personalization service
2. Ads
Ads privacy
Ad topics: 0
App-suggested ads: 0
Ad measurement:
- Allow ad measurement: set to Off
- Reset measurement data: reset
Reset advertising ID: confirmed, reset
Delete advertising ID: deleted
Usage & diagnostics: disabled
3. Remote management
After I tapped it, it said "Installing applications"
After a few minutes, at the second login, I got in and it showed me a Smart Tutor screen. I went to Apps, found it and uninstalled it. It would have allowed the phone to be managed remotely by customer support, I don't know which one.
Facebook
Settings & privacy
Settings, Apps and websites, turned off "Apps, websites and games"
Business integrations
Activity log, Apps and websites off Facebook, Posts from apps and websites: it was empty. Your apps: it was empty.
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
and if you go completely dark whoever is interested can just install a camera near your apartment and get that info anyway. you just can't hide in a city if you are not actively trying to hide, never could either even before tech, it was just more expensive.
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.
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.
There was a TV show in the Netherlands, called Hunted I believe. Contestants had to go on the run and avoid getting caught by the hunting team without doing anything illegal. Or staying to long in a single place, so no camping in the middle of a park (which would technically be illegal anyway).
Long story short, barely anyone got anywhere. Because simply doing an ATM transaction to get the cash already triggered the signal where they were. Not to mention the amount of government owned cameras. As well as being in proximity of anyone still online.
Complete anonymity is virtually impossible, depending on the country.
A good reason to keep a moderate amount of cash hidden on hand. Not so much that losing it would ruin you, but enough that you wouldn’t need to visit an ATM if you actually needed to hide for some reason.
The problem with that show is it is all simulated. They have a camera crew following them round so they cant exactly hide properly.
The show is set up so that if the contestants do anything on a given list (like access ATMs, pay for something with a known card, walking past cctv cameras etc) then the camera crew would notify the hunters. Thats how they got that intel so that they wouldnt need to use actual methods.
I dont think you can use that show as an actual example of somebody on the run. Its so far away from reality and set up to be interesting to the viewer, its just not realistic at all.
My point is that there are a gazillion contact points in any modern environment where you lose anonymity. Not that they can track you in real time like that.
The amount of camera's in and around shopping areas is staggering. And the requirement to have a smartphone on hand is increasing every day, at least in the Netherlands.
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.
π RuView turns commodity WiFi signals into real-time spatial intelligence, vital sign monitoring, and presence detection — all without a single pixel of video.
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"
Slight aside, but I went to look at some of the open issues on that ruvnet repo to see if this is discussed. It's quite an eery feeling reading through them. Every "discussion" is just bots talking to bots.
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
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.)
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.
Yup: https://news.mit.edu/2014/algorithm-recovers-speech-from-vib...
https://en.wikipedia.org/wiki/The_Thing_(listening_device) is a fun read for people who haven't seen it before
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.
In this context, is line of sight with the ability to emit and receive laser radiation at the target not ‘physical access’?
Ah, but of course. How could I forget about my trusty pocket doppler laser interferometer!
This is a "high school project funded with pocket money" level of DIY, with €25 of parts.
Yours is not built in to your watch? You should go and have words with Q.
Microwave beam-forming says what?
I didn’t hear it say that. I guess I’m not the target. :P
Included in the next version of Flipper. /s
Fiber optic interrogators are (for now) expensive and bulky, so I don't think commercial modems are capable of that (yet).
So when AI takes over the world, it will have a convenient tap into every living space of every hoomin. Lovely.
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
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.
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
And reflections on other buildings (which usually cannot be compensated for,) wind bending antennas, etc.
Ah, the old ‘stand in a funny pose so the family can watch the show’. Such a classic. :P
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.
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.
I haven't had a television for 15 years. My life is far better off for it.
I grew up in a family that watched a lot of tv, so Im not ignorant of it. Going to watch a movie is more special, im more likely to read, I go on walks usually multiple times a day in my downtime instead of sitting on a couch.
TVs are lame in my opinion.
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/
Amazing book about similar topics: “Silence on the wire” by Michal Zalewski
https://www.amazon.de/Silence-Wire-Passive-Reconnaissance-In...
Anything in my price range?
What is your price range? You could check your local library for borrowing it.
Now, about the wifi part, why isn't there an Home Assistant extension that detects already room presence magically exploiting all of this??
There is: https://community.home-assistant.io/t/espectre-wi-fi-motion-...
There is with Zigbee: https://github.com/orgs/home-assistant/discussions/960
But this relies on Hue. I would like something at HA level directly, aka a zero-effort solution if you already run a zigbee swarm either directly controlled by HA or via zigbee2mqtt
See also: Van Eck Phreaking https://en.wikipedia.org/wiki/Van_Eck_phreaking
As made popular in Cryptonomicon!
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
Bad actors, and any WiFi capable hardware in your house. There's an official spec for it[1], and some routers already have the option built in. I remember seeing papers about this over 10 years ago, someone at MIT did it for a paper.
Philips Hue also has it built in to their newer lights, where they measure the Zigbee signals. They call it MotionAware[2]. Basically anything with an antenna and a bit of compute is able to do this now.
[1] IEEE 802.11bf-2025 [2] https://www.philips-hue.com/en-hk/support/article/motionawar...
Even philips hue documentation is now vibed
It's probably just AI translated. The original docs are Dutch.
There's an official spec for it[1], and some routers already have the option built in.
~~Comcast~~ Xfinity actually advertises it on the radio as a feature.
Bad actors have been doing that for millennia using their eyes.
This makes it more remote and subtle, but it’s not a new threat.
> So, a bad actor can now know when I'm at my house or not.
A bad actor who wants to act on that information can just wait near your house on a workday morning and watch you leave, likely not to return for the better part of the day. No techno-voodoo required.
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.
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.
Phones and smart TVs, probably other appliances. My SO used to be surprised to receive ads about stuff we talked about minutes before. I finally looked at her phone, disabled a bunch of things in the stock Android settings, those timely ads went away. I didn't even have to install Blockada, uBO for FF (and uMatrix and other addons) like I do on my devices.
Can you elaborate on what did you disable?
I feel like by disabling ads in most devices, I'm also taking away the best source of information on what bad actors (here ad companies) managed to exfiltrate about me.
If there only was a way to sell ad space about myself and learn from it what others know.
Most companies don't allow you to turn off data collection easily. What they do allow is turning off the response to that data (displaying relevant ads).
I mailed her a summary for future reference. It's quite detailed but it was not in English and the phone was not in English too. So forgive me but I asked Claude to translate it and guess the right menu and option names for an English Android. It should be enough to give you the idea of what I did. It was a Samsung phone, not a S series.
Here it is:
---
Tapping <first name last name> at the top of Settings opens the Samsung account notice, and the Terms of Service show as not accepted. I'm leaving them unaccepted and not continuing.
1. Security and privacy
Controls and alerts: left Microphone access on, because permissions will be set individually per app.
More privacy settings:
Send diagnostic data
Set to Off
Samsung
Improve personalized ads based on data from this phone: you have to go to the Samsung account settings.
Receive news and special offers on this phone: same
Customization Service for your phone: same
Going to Accounts and backup > Samsung Cloud > Data backed up: there is no data being backed up to Samsung.
Going to Samsung Cloud shows that Bluetooth, Calendar, Contacts and Wi-Fi are synced.
Google
Google personalization service: set to Off
Permission manager:
Switched to Ask every time:
Still set to "Allowed only while in use": Camera and WhatsAppActivity controls
Web & App Activity: turned off, but I did not delete the history
Timeline (Location History): was already off since January 1, 2025
YouTube History: left on
Personalized ads:
Everything is disabled, as expected after turning off the Google personalization service2. Ads
Ads privacy
Ad topics: 0
App-suggested ads: 0
Ad measurement: - Allow ad measurement: set to Off - Reset measurement data: reset
Reset advertising ID: confirmed, reset
Delete advertising ID: deleted
Usage & diagnostics: disabled
3. Remote management
After I tapped it, it said "Installing applications" After a few minutes, at the second login, I got in and it showed me a Smart Tutor screen. I went to Apps, found it and uninstalled it. It would have allowed the phone to be managed remotely by customer support, I don't know which one.
Facebook
Settings & privacy
Settings, Apps and websites, turned off "Apps, websites and games"
Business integrations
Activity log, Apps and websites off Facebook, Posts from apps and websites: it was empty. Your apps: it was empty.
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
and if you go completely dark whoever is interested can just install a camera near your apartment and get that info anyway. you just can't hide in a city if you are not actively trying to hide, never could either even before tech, it was just more expensive.
Really? They can’t seem to pick up a conversation happening directly in front of them.
Or they could just knock on your door and see if you answer.
They already knew this from your cell phone not being in airplane mode.
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.
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.
There was a TV show in the Netherlands, called Hunted I believe. Contestants had to go on the run and avoid getting caught by the hunting team without doing anything illegal. Or staying to long in a single place, so no camping in the middle of a park (which would technically be illegal anyway).
Long story short, barely anyone got anywhere. Because simply doing an ATM transaction to get the cash already triggered the signal where they were. Not to mention the amount of government owned cameras. As well as being in proximity of anyone still online.
Complete anonymity is virtually impossible, depending on the country.
A good reason to keep a moderate amount of cash hidden on hand. Not so much that losing it would ruin you, but enough that you wouldn’t need to visit an ATM if you actually needed to hide for some reason.
The problem with that show is it is all simulated. They have a camera crew following them round so they cant exactly hide properly.
The show is set up so that if the contestants do anything on a given list (like access ATMs, pay for something with a known card, walking past cctv cameras etc) then the camera crew would notify the hunters. Thats how they got that intel so that they wouldnt need to use actual methods.
I dont think you can use that show as an actual example of somebody on the run. Its so far away from reality and set up to be interesting to the viewer, its just not realistic at all.
My point is that there are a gazillion contact points in any modern environment where you lose anonymity. Not that they can track you in real time like that.
The amount of camera's in and around shopping areas is staggering. And the requirement to have a smartphone on hand is increasing every day, at least in the Netherlands.
there is always the risk of the isolated Faraday caged house
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.
IEEE ISAC, look it up
Thank you for more paranoia
Awareness of possibilities is not paranoia. One implies sickness. Healthism?
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
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"
Slight aside, but I went to look at some of the open issues on that ruvnet repo to see if this is discussed. It's quite an eery feeling reading through them. Every "discussion" is just bots talking to bots.
yeah, now I gotta unplug TV too
Thats nothing, my old tv could predict incoming phone calls.
When I was young I could tell when the neighbours turned on their tv by the UHF whine.
see also, presence detection of humans via wifi signals: https://arxiv.org/html/2308.06773v2