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> We’ve normalised the idea that Bluetooth is always on. Phones, laptops, smartwatches, headphones, cars, and even medical devices constantly broadcast their presence. The standard response to privacy concerns is usually “nothing to hide, nothing to fear.”
I guess anything you send out can be used to profile you.
Some of my friends live on a farm near a semi busy road, however far enough from other farms to not be able to receive their wifi. They showed me their router logging all the wifi accesspoints that appear/disappear. There where A LOT of access points named "Audi", "BMW", "Tesla" etc. similar to those devices leaking bluetooth data. We had a discussion that it would be easy to determine who was passing by at what times due to these especially when you can "de-anonymize" the data for example link it to a numberplate.
I believe shopping malls often use such signals (wifi, bluetooth) to track what your travel pattern through the mall is. They know what section of the store you spend most of your time in and what storefronts you stall at.
You can do this for much cheaper - all four of your tires are broadcasting a unique ID to report tire pressure, the radio to pick it up is cheap (because cars), and TPMS has no facility to randomize or otherwise secure this.
It’s actually even easier, your car has a plate on the front with a unique ID that a camera scans, often to automatically track your park time for ticketing.
I can’t really care about obscure Bluetooth tracking when every business has CCTV doing facial recognition.
Not all cars have active TPMS. my Volvo xc90 had them but in later models they switched back to passive ones. So it is not even a given for higher end models.
> I believe shopping malls often use such signals (wifi, bluetooth) to track what your travel pattern through the mall is. They know what section of the store you spend most of your time in and what storefronts you stall at
In the EU this is forbidden unless they explicitly ask your permission. They can still gather aggregate stats but they cannot build a profile on you.
>There where A LOT of access points named "Audi", "BMW", "Tesla" etc.
That's one of the funniest things about wardriving with Wigle on your phone. I can often see the SSID of "Jennifer's Equinox", "Jacks Suburban" right after I get cut off by someone in said vehicle. The vast majority of car bluetooth/wifi I see tends to have varying amounts of identifying information. It's almost as bad as the fact that apple still defaults to Jacks iPhone/iPad etc with no option to rename the device until you've finished setting it up.
Companies are not out to protect us with default settings and the majority of users need to wake up to this fact.
This might just be me being uninformed as someone who doesn't drive but how are you seeing what wifi networks are available so quickly right after being cut off? My very naive instinct is that looking at your phone or opening up a menu with the available wifi networks on your car's display seems like it would require a noticeable decrease in attention to the road, so I'd almost expect an uptick in being cut off from other people who are annoyed with your driving.
Small town, phone is on a dash mounted holder. Sometimes I leave Wigle up just to eye every now and then to see how much crap I'm picking up while war driving.
I am not without sin when it comes to driving a car.
What would be next level wardriving would be to break into their Bluetooth and have a conversation about their driving habits.
It can be done, relatively easily.
Don't worry about Tesla's being tracked. Via Bluetooth this has existed for at least 7 years [1] (was mentioned on HN as well). Tesla know (also for 7 years), Musk doesn't care 'since license plates can also be tracked'.
I used it in train stations, and get hits when passing highways via train or bus. Esp. fun if you stand still due to traffic lights or traffic jam, since you can try to get a visual.
The only lesson to be learned here is that it allowed one to learn in 2019 Musk is overrated. But you can also learn that lesson from the book The PayPal Wars which predates this by 15 years.
> I believe shopping malls often use such signals (wifi, bluetooth) to track what your travel pattern through the mall is. They know what section of the store you spend most of your time in and what storefronts you stall at.
Not allowed in EU.
> Not allowed in EU.
I'm surprised, I know for a fact that some stores definitely have the ability to do that on their hardware.
> I believe shopping malls often use such signals (wifi, bluetooth) to track what your travel pattern through the mall is. They know what section of the store you spend most of your time in and what storefronts you stall at.
Yes, I remember Cisco had a product like this all the way back in 2011. They could pinpoint a customer to an exact position inside a store using triangulation, they would know which shelf you spent time in front of etc. In the 15 years since then, I expect the technology is much scarier and intrusive.
iBeacon. They know what shelf you're standing in front of. What products you touch and read.
Ever been in an Apple store? Look up. In the dark voids between the edge-to-edge backlit ceiling. There are secrets there. Watching you.
Macys pioneered it before there even were Apple Stores. Back when most people didn't even know their phones had Bluetooth.
There's an Android app that can find devices, make profiles, and you can track location for as long as they're connected. So you can profile passerbys and even get notified when the profile passes through again. I forgot what is was called
Are you thinking of BLE Radar?
Years ago when BT beacons were newish, I was talking to an AdTechBro that wanted to create the ability from Minority Report where the kiosk recognizes a user, not by eye scans but by recognizing mobile device, so they could offer a personalized whatever. The creepiness wasn't something they eased into. It was pretty much instant.
> We had a discussion that it would be easy to determine who was passing by at what times due to these especially when you can "de-anonymize" the data for example link it to a numberplate.
You could also read the numberplate directly with OpenALPR. It can be finicky to set up a camera to do this reliably in all conditions (particularly at night and high speed) but once done you could detect any car passing, not just ones with wifi access points.
When the law requires us to have numberplates, I think this just has to be considered public information for anyone who is nearby or can leave a camera nearby. It's not ideal to leak it in additional forms that might be easier for people to grab (say, with an ESP32), but it's a matter of degree rather than of kind.
But yeah, I'm with you on some of these others, particularly the medical devices. That's not great.
There's a difference between public and Public. I go outside with my face visible and I don't mind if my neighbors see me. I do mind if my neighbors stand outside my door with a notepad sketching faces every time they see me or anyone else, especially if they're selling the data. Systematic tracking that isn't subject to the constraints of human memory and apathy fundamentally changes the equation.
> constraints of human memory and apathy
i like that a lot, brother, thank you!
The GrapheneOS variant of Android will disable both Bluetooth and WiFi after a set period of inactivity.
There is also a Bluetooth shutoff app on F-Droid.
https://f-droid.org/en/packages/com.mystro256.autooffbluetoo...
I have also put an Airtag clone in my car (Loshall in iOS mode). That is probably leaking my arrival times. My water meter is also now bluetooth.
I disable bluetooth on my phone, though periodically I find that it's back on.
Edit: iOS
I have the opposite experience: GrapheneOS has an option to automatically turn your bluetooth off after a configurable period of not being used. So when I need to use bluetooth, I turn it on like normal. Then, without thinking about it, it automatically turns off. The end result is my bluetooth is only ever on for a couple hours each month when I'm making phone calls.
I only see an option to turn back on tomorrow. How do you find this option?
Did not realize I could do that! Thank you!
With iOS the easiest way to make sure it off and stays off is to build a shortcut to cut off wifi/bluetooth. Otherwise it's typically off until you get geolocated as being back home/work and wifi comes back on.
I have a "store mode" button that just kills wifi/bt that I hit before I go into any store.
what do you gain doing this?
Peace of mind that I'm not being tracked around the store by wifi/bt, and/or having my device fingerprinted for further identification on future visits.
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I miss wired headphones for this purpose. It's the only reason I even have BT enabled.
Android now has an option to enable it every day.. (I have it disabled).
> I believe shopping malls often use such signals (wifi, bluetooth) to track what your travel pattern through the mall is.
Many places do this. The department stores in the mall, target, even grocery stores do it.
> even medical devices constantly broadcast their presence
I mean yes, said medical devices are a whole lot less useful to me if they are not transmitting data. For some of this stuff you can't have your cake and eat it too.
I was wardriving my neighborhood and realized my elderly neighbor's CPAP machine is broadcasting some type of BT signal 24/7. I imagine it's transmitting some important stats, but it did make me have a 2nd thought about medical devices being IoT or BT enabled.
> being IoT or BT enabled
Please don’t conflate these two. I have lots of BLE wearables and other sensors. They only send data to my own computer which I control, unlike IoT devices which by definition send to a third party on the Internet. To me it is far more important to protect against strangers on the Internet versus someone wardriving the neighborhood.
On a related note, did you know that EU has a Radio Equipment Directive (RED 2014/53/EU) that came into effect in 2025. It all but guarantees that such Bluetooth communication will be encrypted.
CPAP machine is broadcasting some type of BT signal 24/7
A lot of them also have cellular modems.
It's marketed to the patient as a way to send data to their doctor.
However, the most common use is for the health insurance company to make sure they're being used because the insurance company doesn't want to pay for something that is gathering dust. If it doesn't connect for a certain amount of time, the insurance company will send a letter to the patient threatening to stop paying for the machine.
You can get the insurance company off your back temporarily by turning off the cellular connection and claiming that there's no service in your home. But you'll have to bring the SD card to your doctor every six months or so, so the insurance company can see it.
/Works in healthcare
What forces devices to constantly stream data? You can batch updates and probably save power thanks to it.
Because these BLE devices are so cheap that they don’t have storage. And BLE transmission is already very power efficient: the power consumption of BLE is probably the same order of magnitude as powering flash storage.
There’s a middle ground here. There is no technical reason a pacemaker constantly broadcasts itself - there is ways to allow communication to such devices without yelling your name all the time. And there is definitely no reason for such a name to be a unique identifier.
I mean if not a name, how would a mac id be any different?
I can assure you this has been talked about and is known and it's why you still find a headset port on devices handed out to government officials, though most of them ignore the advice to not use bluetooth.
This is not very different from collecting visual cues. You can notice a delivery van arriving. You can see the driver's face, same with passers-by. The biggest difference is that a camera needs to be more conspicuous, while a BT receiver can be invisible and undetectable. Much cheaper, too.
Tangential, sort of: in the early days of mobile phones for the masses, when there was no WiFi/3G in the underground, I will often enable Bluetooth in my phone, look for nearby devices and try to match names and looks.
That was before everyone had their "John's IPhone" or "Samsung A55" boring names everywhere and some of us cared to personalise our device's name.
Anyone else played this game?
hmmmmm...
2006, sat in a job interview. Interviewer says he'll Bluetooth over a file to me - what's by phone's name?
2006, the year that Tool's 10,000 Days had been released, which I was enjoying and, being a bit of an Edge Lord, I'd named my device after a lyric from Vicarious - which, IIRC fit perfectly into the name space and made me very happy:
> ILikeToWatchThingsDie
Excellent. Still got the job though!
Hah, I change my device name and wifi hotspot all the time...
"[Agency-acronym] Surveillance Van #43/44/etc.."
Yeah, but it stopped pretty soon stores figured out that they could flood you with advertisements over Bluetooth. In some places it was bad enough that I had to turn off Bluetooth.
How did this play out? Were the ads from an app from the store that you had installed? Or did they spam you over SMS because they associated your bluetooth info with an account you have with the store, or contact info they bought from a third party?
> Were the ads from an app from the store that you had installed?
This is my main concern over installing apps in general but specifically store apps. I've noticed that grocery stores are moving past existing loyalty cards and want you to use their apps for exclusively available digital coupons. The prices I'm seeing are very compelling and are on top of existing loyalty card discounts, and I could see lots of people using the app because of it. The assumed amount of abuse keeps me from lemminging my way through the store.
Yep 100% did the same.
It was interesting to see what people named stuff as even back then I figured you could use that metadata for tracking devices...but even more interesting was looking at the Mac address to see the manufacturer and try and find some rare or cool device.
Did you ever try to communicate with them?
I do the reverse. I set my wifi hotspot or bluetooth to "MetPoliceUnit355" and I look for people making faces or looking around.
Ring: thank you for the idea, "Introducing Ring Face-Off, face masks covering faces during a break-in is no an issue for Ring, we will track the thieves until they reveal their face to our Ring network."
Bluetooth desperately needs mac randomization. Wifi mac randomization is welcome, but it doesn't do much when many (most?) people have bluetooth accessories broadcasting a persistent identifier whenever they're on.
> Bluetooth desperately needs mac randomization.
Bluetooth already has a well developed MAC randomization scheme.
Lookup "resolvable private address". The short of it is, your phone can find your headphones or vice-versa, despite one or both having random addresses. The addresses can be regenerated or rotate at an interval (say 15 minutes). The first part of the address is a nonce (pRand), and the rest of the address is a 24-bit hash of pRand with an identity resolving key (IRK). So the other party just listens passively for addresses, and sees if any of them happen to have the right hash.
I don't think this is as airtight as people think it is. Certainly, if you are following somebody and one address disappears right as another appears (rotation), it's quite easy to infer the new/old addresses belong to one device. I tried briefly to convince the Android developers to synchronize that rotation globally.
You can also probably infer that if you see a pair of random MACs arrive, and they have a certain pattern of timing and payload size, you can say with some certainty that they are particular devices, say an iPhone and an Apple Watch. But that requires sophisticated equipment since most Bluetooth LE communication is over a non-cryptographic frequency hopping arrangement.
Lastly, radio fingerprinting is widely known in academia, but requires special equipment.
Random Bluetooth MACs are already possible. iOS devices have been doing it for years alongside the random Wi-Fi MACs.
The part about passively detecting delivery driver patterns from a home office is wild. I knew BLE was chatty but being able to correlate device pairs (phone + watch) to build movement profiles with just a Pi is genuinely unsettling. Makes me want to audit which of my devices are broadcasting when they don't need to be.
"We agreed on a 150-day disclosure window". Isn't that longer than Google Project Zero gives to release fixes?
About 10 years ago i had HomeAssistant running and thacking my bluetooth devices. It does so per default by jus memorizing a mac adress an recording when it's visible and when not. No need for pairing or anythung. It also stores the custom name if available.
Anyway, the default dashboard also automatically generated a view when my neighbours "Katie's iPhone' was at home and when not, until I actively deleted it and the data it stored.
Similar story - "Home assistant picked up my neighbours Bluetooth toothbrush and now I can see when they brush their teeth"
https://www.reddit.com/r/homeassistant/comments/1306pcw/home...
Wonder what the difference is between this and: https://github.com/ArgeliusLabs/Chasing-Your-Tail-NG
That one doesn't seem to do bluetooth at all, I think?
you said " blocking ads network-wide with AdGuard". It's better to block it with a Pihole.
This could be used for a truly eye-opening art installation: a screen that as you walk by it, tells you when you were last there..
Even wilder would be to buy data on you in real time and display that.
The Hollywood movie Minority Report has a scene where an advertising display personalizes the ad by your name. https://www.youtube.com/watch?v=7bXJ_obaiYQ
The project describes - and shows - a web interface.
Is there a simple CLI interface that can be redirected or pipelined into other tools ?
The article says the data is in a SQLite database.
Yes I see that and I wonder if the project includes a CLI tool.
> This isn’t about paranoia. It’s about understanding the trade-offs
> Bluetooth mesh networks—no internet required, no servers, no phone numbers
LLM slop. Both the article and the Python script
I suspect the e-scooters left around town (Lime, Bird, etc) are massive Bluetooth / LoRa dragnets. You pay them to increase coverage or visibility to social hot spots.
Wow e-scooter wardriving is something I hadn’t thought of. Could be happening somewhere
ran something similar on a home network once and was surprised how many of my neighbors' devices showed up with full manufacturer names and model numbers. you don't even need to try hard.
Wait doesn't BLE randomize the UUIDs?
Has anyone ever studied what happens with Bluetooth contention where thousands of people are gathered in a small space?
Like a marathon mass-start with 10,000 sometimes 20,000 or more people
How does bluetooth handle that? Or it doesn't?
In my experience, just fine. I recently ran a large (~30k) marathon and my AirPods and watch never glitched once, streaming the whole time including in the packed start corrals. I had the same thought about RF contention, but Bluetooth didn't seem to care.
Even licensed wireless stops functioning. All circuits are busy.
Doesn't HackRF with Cha0s do something similar?
And kismet
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I read an article in 2012 about the feds (DHS?) placing Bluetooth enabled devices along I5 in Seattle. They were able to make profiles of people based on what Bluetooth devices they had in their cars. Is anyone familiar with this? I've periodically tried to Google it and can't find anything about it
Possible, but they buy data from the carriers with similar profile possibilities. The DEA operates long standing and pervasive surveillance in “drug corridors” like I-95 from Maine to Miami. They do things like LPR and grabbing passenger pictures.
If Bluetooth is used, it may be a way to get a count of passengers or if the passengers change. I know based on newspaper accounts that they are particularly interested in cars that stop in Philly or Baltimore.
This stuff is frequently used against cops too so they may use the tech in similar ways. If you’re someone worried about getting raided, spotting a large number of new signals at the front door is an early warning potentially.
I remember an art exhibit by an online privacy activist made where it’d ping people’s phones to get a list of “known WiFi networks” and then display them on a screen in a room.
Each person would get a unique fingerprint of named network locations
I believe Houston used bluetooth to measure congestion on 45.
Crafted by Rajat
Source Code