Meta devised an ingenious system (“localhost tracking”) that bypassed Android’s sandbox protections to identify you while browsing on your mobile phone — even if you used a VPN, the browser’s incognito mode, and refused or deleted cookies in every session.
This is the process through which Meta (Facebook/Instagram) managed to link what you do in your browser (for example, visiting a news site or an online store) with your real identity (your Facebook or Instagram account), even if you never logged into your account through the browser or anything like that.
Meta accomplishes this through two invisible channels that exchange information:
(i) The Facebook or Instagram app running in the background on your phone, even when you’re not using it.
(ii) Meta’s tracking scripts (the now-pulled illegal brainchild uncovered last week), which operate inside your mobile web browser.
A robot told me: The Meta/Yandex exploit worked by having JavaScript running on a website (such as Meta Pixel) connect from the browser to a native app on the same device via the localhost (127.0.0.1) interface, using HTTP, WebSocket, or WebRTC. This communication occurs entirely within the device and does not traverse the network in a way that browser extensions like uBlock Origin can intercept or block. Browser extensions generally cannot block or even see requests made to localhost sockets, especially when those requests are initiated by scripts running in the browser and targeting native apps on the same device
Yeah but if the script which initiates the connection to the local server is blocked there’s no connection to intercept in the first place.