Hacker News new | ask | show | jobs
by jacquesm 3014 days ago
True, but that's something your cell provider (and the providers of other base stations your phone has pinged) has access to, not your typical website.

But you are 100% correct that the cell network knows to within a rough approximation where you are and how fast you travel. This information is also used to predict where and when the next cell-hand-off will happen.

1 comments

Yep - as always in security, it's important to know who your adversary is.

If your adversary is the NSA(/GRU/Mossad/etc) - you're fucked. Throw away all your electronic devices, torch your house, and hope you make it to Belize before they shut the borders to you.

If your adversary is Law Enforcement, they'll get cell tower data (quite likely without a warrant by just asking), and they'll then mislead a court and jury about how accurate that data is: https://www.newyorker.com/news/news-desk/what-your-cell-phon...

This link: http://urgentcomm.com/psap/different-strokes says that since '05 wireless carriers in The US have been required to do better than just "which cell tower you're connected to", but for some percentage of connections they're required to provide 50 or 150m location accuracy - which they can apparently do using three cell towers and triangulation. Since they're happy to hand over cell tower data to law enforcement when asked (or possibly when asked with a warrant) - I wouldn't bet against then handing this E911 Phase 2 level of location accuracy over.

Somewhat more worryingly... The cell providers seem to be happily monetising that data too: https://techcrunch.com/2017/10/15/mobile-phone-companies-app... https://www.theverge.com/2013/4/9/4187654/how-carriers-sell-...

Now out of the four big technology companies - two of them own a mobile OS and so can do whatever-the-fuck they want with your phone if you're "in their camp" and of the remaining two, one of them actually sells you stuff to make a living, the other makes their money by surveilling you.

With Facebook's warchest - what do you reckon the chances are of them _not_ buying cellphone location data on the open market to add to their advertising-marketing machine?

I'm not saying I know they are - but I do know that the data about location down to perhaps 50m accuracy or less is legally required to be available to the cell operators - and they've been caught in the past selling that data - and Facebook have _very_ deep pockets to pay for data to match against theirs. (And there is almost _zero_ chance that whatever the cell companies might to to "anonymise" that cell location data, Facebook wouldn't be able to de-anonymise it by correlating to to other data they collect.)

But yeah, having your phone use a VPN no doubt helps...

> With Facebook's warchest - what do you reckon the chances are of them _not_ buying cellphone location data on the open market to add to their advertising-marketing machine?

I don't think they would have to pay for it. They're just going to give the phone company a nice fat discount on their advertising campaign. That way they don't have to own up to selling your data either, win/win. /s

Mobile phone location data is so valuable that there are whole companies dedicated to 'enriching' mobile phone OpenRTB requests with location data.

https://www.iab.com/guidelines/real-time-bidding-rtb-project...