7 ms·

Don't they randomize their broadcast ID? I know both Android and iOS scramble the WiFi MAC address by default, it would be odd if they didn't take the same prec

Don't they randomize their broadcast ID? I know both Android and iOS scramble the WiFi MAC address by default, it would be odd if they didn't take the same precaution with Bluetooth.

boznz 2y ago
Sci-Fi books and it was a sentient AI, I can do anything I want in that situation :-)
csdvrx 2y ago
The randomization doesn't matter: you can very easily link the addresses if you have a few datapoints, even if it's just the time you observed the addresses: the basic method is discussed in https://inria.hal.science/hal-03045555/document https://inria.hal.science/hal-03045555/document See https://inria.hal.science/hal-02394629v1 https://inria.hal.science/hal-02394629v1 for the theoretical bases then hop to https://samteplov.com/uploads/shmoocon20/slides.pdf https://samteplov.com/uploads/shmoocon20/slides.pdf for an example applying to Apple devices Those who said the randomization and other techniques were sufficient were wrong: https://petsymposium.org/popets/2020/popets-2020-0003.pdf https://petsymposium.org/popets/2020/popets-2020-0003.pdf will show you how they changed their mind :) It's not just apple: google nearby has also been reversed: https://publications.cispa.saarland/2748/ https://publications.cispa.saarland/2748/ and https://www.ndss-symposium.org/wp-content/uploads/2019/02/ndss2019_06B-3_Antonioli_paper.pdf https://www.ndss-symposium.org/wp-content/uploads/2019/02/nd... talks about attacks, but there's no need for that: just find identifiers that let you link the addresses Even if you don't have any identifiers, the Bluetooth address randomization happens only about every 15 minutes: the manufacturer specific data in the public advertisement (or even the frequency and the length of these advertisements) during these 15 minutes periods can be used for linking the randomized addresses
- lxgr 2y ago
  That attack requires continuously monitoring a given device or area though, right? In other words, you could possibly track a given device through an area with enough sensors, e.g. a store, but not across visits.
  - csdvrx 2y ago
    > That attack requires continuously monitoring a given device or area though, right? The "randomization" seems to be a pseudo-randomization: with the seed and the timestamp, you should be able to deduce the future "randomized" addresses.
    - lxgr 2y ago
      Not with a cryptographically secure pseudorandom number generator, and constructing one doesn't seem hard to do, given that LE devices will need to support AES anyway.
AStonesThrow 2y ago
Google has lately been far overstepping their utility with “security measures” which I definitely don’t need and often make everything more annoying and difficult. Ex: blocking 3rd party cookies always now. Breaks countless websites which I need to work reliably. “Manage unused website/app’s permissions” even after I specifically granted them! Randomized virtual credit card numbers in Wallet: for no good reason, you thoroughly fucked up a refund attempt for me, >$500! And randomized MAC addresses by default for EVERY. SINGLE. SSID. It’s unhinged. It’s fake protection. As a matter of fact, I do not enjoy my devices lying to my ISP, or to my college campus, my medical clinic, or to my employers. Device, please identify yourself without wearing a fuckin’ Groucho mask on top, and put on your big boy pants.
- HeatrayEnjoyer 2y ago
  Never thought I'd hear someone complain Google takes privacy too seriously.
  - AStonesThrow 2y ago
    Google is extremely conscious for their privacy of their data which they’re collecting from you. Google calls it “my privacy” but it’s not their business model to keep my stuff private to me but to Google and their partners. https://m.xkcd.com/1150/ https://m.xkcd.com/1150/ Google is trying to keep their own secrets like what their hardware MAC address really is, (because Google themselves are tracking everyone’s radio-enabled devices in every public space with far more sophisticated methods) or hide/virtualize my credit card details, and protecting the card from crackers who wear hoodies, build EBM playlists, and use Firefox? that is a side-effect at best, especially considering how they are already a crazy non-bank middleman 3rd party with a miasma of shifting TOS and hundreds of advertising partners salivating to know what you paid for 3 milliseconds ago. Sheesh.

Don't they randomize their broadcast ID? I know both Android and iOS scramble the WiFi MAC address by default, it would be odd if they didn't take the same precaution with Bluetooth.

boznz 2y ago

Sci-Fi books and it was a sentient AI, I can do anything I want in that situation :-)

csdvrx 2y ago

The randomization doesn't matter: you can very easily link the addresses if you have a few datapoints, even if it's just the time you observed the addresses: the basic method is discussed in https://inria.hal.science/hal-03045555/document https://inria.hal.science/hal-03045555/document See https://inria.hal.science/hal-02394629v1 https://inria.hal.science/hal-02394629v1 for the theoretical bases then hop to https://samteplov.com/uploads/shmoocon20/slides.pdf https://samteplov.com/uploads/shmoocon20/slides.pdf for an example applying to Apple devices Those who said the randomization and other techniques were sufficient were wrong: https://petsymposium.org/popets/2020/popets-2020-0003.pdf https://petsymposium.org/popets/2020/popets-2020-0003.pdf will show you how they changed their mind :) It's not just apple: google nearby has also been reversed: https://publications.cispa.saarland/2748/ https://publications.cispa.saarland/2748/ and https://www.ndss-symposium.org/wp-content/uploads/2019/02/ndss2019_06B-3_Antonioli_paper.pdf https://www.ndss-symposium.org/wp-content/uploads/2019/02/nd... talks about attacks, but there's no need for that: just find identifiers that let you link the addresses Even if you don't have any identifiers, the Bluetooth address randomization happens only about every 15 minutes: the manufacturer specific data in the public advertisement (or even the frequency and the length of these advertisements) during these 15 minutes periods can be used for linking the randomized addresses

lxgr 2y ago
That attack requires continuously monitoring a given device or area though, right? In other words, you could possibly track a given device through an area with enough sensors, e.g. a store, but not across visits.
- csdvrx 2y ago
  > That attack requires continuously monitoring a given device or area though, right? The "randomization" seems to be a pseudo-randomization: with the seed and the timestamp, you should be able to deduce the future "randomized" addresses.
  - lxgr 2y ago
    Not with a cryptographically secure pseudorandom number generator, and constructing one doesn't seem hard to do, given that LE devices will need to support AES anyway.

AStonesThrow 2y ago

Google has lately been far overstepping their utility with “security measures” which I definitely don’t need and often make everything more annoying and difficult. Ex: blocking 3rd party cookies always now. Breaks countless websites which I need to work reliably. “Manage unused website/app’s permissions” even after I specifically granted them! Randomized virtual credit card numbers in Wallet: for no good reason, you thoroughly fucked up a refund attempt for me, >$500! And randomized MAC addresses by default for EVERY. SINGLE. SSID. It’s unhinged. It’s fake protection. As a matter of fact, I do not enjoy my devices lying to my ISP, or to my college campus, my medical clinic, or to my employers. Device, please identify yourself without wearing a fuckin’ Groucho mask on top, and put on your big boy pants.

HeatrayEnjoyer 2y ago
Never thought I'd hear someone complain Google takes privacy too seriously.
- AStonesThrow 2y ago
  Google is extremely conscious for their privacy of their data which they’re collecting from you. Google calls it “my privacy” but it’s not their business model to keep my stuff private to me but to Google and their partners. https://m.xkcd.com/1150/ https://m.xkcd.com/1150/ Google is trying to keep their own secrets like what their hardware MAC address really is, (because Google themselves are tracking everyone’s radio-enabled devices in every public space with far more sophisticated methods) or hide/virtualize my credit card details, and protecting the card from crackers who wear hoodies, build EBM playlists, and use Firefox? that is a side-effect at best, especially considering how they are already a crazy non-bank middleman 3rd party with a miasma of shifting TOS and hundreds of advertising partners salivating to know what you paid for 3 milliseconds ago. Sheesh.