We’re not sure if this is art, anti-snooping guerilla warfare, or just a cheeky hack, but we do know that we like it! [Jasper van Loenen]’s Linger keeps the SSIDs that your cell phone (for example) spits out whenever it’s not connected to a WiFi network, and replays them after you’re gone.
Some retail stores and other shady characters use MAC addresses and/or the unique collection of SSIDs that your phone submits in probe requests to fingerprint you and track your movement, either through their particular store or across stores that share a tracking provider. Did you know that you were buying into this when you enabled “location services”? Did the tracking firms ask you if that was ok? Of course not. What are you going to do about it?
Linger replays the probe requests of people who have already moved on, making it appear to these systems as if nobody ever leaves. Under the hood, it’s a Raspberry Pi Zero, two WiFi dongles, and some simple Python software that stores probe requests in a database. There’s also a seven-segment display to indicate how many different probe-request profiles Linger has seen. We’re not sure the price point on this device is quite down to “throwie” level, but we’d love to see some of these installed in the local mall.
The fact that your smartphone leaks data that’s able to fingerprint and track you should be old news to our crowd. But don’t just take our word for it, try it out yourself! With one Raspberry Pi in your backpack, you could log all the signals around you. Add a few more nodes and you could even try to triangulate your phone within your own home. Just because it’s a creepy invasion of privacy doesn’t mean it’s out of the realm of the DIY hacker.