Privacy-friendly browsers like Firefox, Safari, and Brave have taken measures to prevent user tracking through third-party cookies for a while now. To get around this, tracking companies have came up with ‘redirect tracking’ to continue follow users’ movement across the web. Redirect tracking is an advanced technique that circumvents third-party cookie blocking by making use of first-party cookies instead.
To achieve this, trackers drop a first-party cookie when you visit a website. When you click an ad or a ‘buy’ button to visit the retailer’s website, you are momentarily taken to one or more tracker websites before being redirected to the intended destination. During this momentary ‘stopover,’ the tracker associates tracking data with the identifiers they have stored in first-party cookies. This happens very quickly for a user to notice.
Firefox aims to fight redirect tracking with a new feature introduced in version 79. To reduce redirect tracking, Firefox will now automatically clear cookies and site data from tracking sites every 24 hours. By clearing any cookies and site data stored by known trackers, Firefox will prevent redirect trackers from being able to build a long-term profile based on users’ browsing activities.
WebKit — Apple’s browser engine on which Safari and all iOS web browsers are based — released Intelligent Tracking Prevention 2.0 in June. With ITP 2.0, WebKit also blocks redirect tracking — which it refers to as bounce tracking.
While both WebKit and Firefox are fighting the same tracking method, their implementations have some differences. Firefox relies on the Tracking Protection list maintained by Disconnect. WebKit uses on-device machine learning to identify a domain’s tracking abilities. For a website to keep its cookies from being purged, a user has to interact with the website. Firefox considers user scrolling as an interaction. WebKit, however, counts a tap, click, or form entry as interaction but not scrolling.
Firefox 79 has been launched last week for Windows, macOS, and Linux. The update will be rolling out for all users in coming days.