Comment by dm2 | Hacker News Reader

Comment by dm2 | Hacker News Reader

Here is a video about the Euclid software. This service makes the Wifi tracking even scarier because it can track across different stores, then they probably sell that data. http://www.youtube.com/watch?v=q4W1GIRHC_4 http://www.youtube.com/watch?v=k86DxCqfHjY

Here is a way to opt-out of this particular service. https://signup.euclidelements.com/optout

It seems like it would be trivial to tie in the location tracking with the products someone purchases and if you are using a rewards card (like most grocery stores have) then the store has all of your information tied to your MAC address.

It's not just stores, any place could have these systems set up. Malls, airports, stadiums, schools, or even your workplace.

Is it possible to obscure or modify a phones wifi strength when not connected to a network to prevent this tracking?

I just watched the video. They mention that they use equipment from http://www.aerohive.com/, which just seem to be normal wifi infrastructure.

It seems like only people who actually connect to the wifi can be tracked. There's no way to harvest the MAC address of a wifi device that hasn't connected to your network, is there?

As a store, this seems to be not that valuable to me. I can't imagine that very many shoppers actually take the time from shopping to decide to connect to your wifi. I get that they only need to do this once, and after that, it will auto-reconnect. I'm still not buying it as an effective tracking method.

There's no way to harvest the MAC address of a wifi device that hasn't connected to your network, is there?

Yes, there is. If you set your WLAN interface to monitor mode and run tcpdump or similar, you can look at packets passing by, even if you're not connected to a network at all. I built a Wifi tracking system this way when I was in school.

Thanks for that. I wanted to understand how this was working.

This seems like a pretty powerful data source to use for all sorts of things, if it's always accessible like that. A world readable cookie for every yuppie and hipster on the planet!

(I've evaluated several wifi tracking systems) - your device doesn't have to connect to the network to be tracked; wifi just has to be on. While searching for nearby networks, devices constantly chirp their MAC address.

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