Friday, June 8, 2018

Intelligent Tracking Prevention 2.0

ITP 2.0, as opposed to earlier versions, immediately partitions cookies for domains determined to have tracking abilities. The previous general cookie access window of 24 hours after user interaction has been removed. Instead, authenticated embeds can get access to their first-party cookies through the Storage Access API. The API requires that the user interacts with the embedded content.

[…]

ITP 2.0 has the ability to detect when a domain is solely used as a “first party bounce tracker,” meaning that it is never used as a third party content provider but tracks the user purely through navigational redirects.

[…]

Through our research, we found that cross-site trackers help each other identify the user. This is basically one tracker telling another tracker that “I think it’s user ABC,” at which point the second tracker tells a third tracker “Hey, Tracker One thinks it’s user ABC and I think it’s user XYZ.” We call this tracker collusion, and ITP 2.0 detects this behavior through a collusion graph and classifies all involved parties as trackers.

[…]

ITP’s purging of website data does not prevent trackers from receiving the so called referrer header which reveals the webpage the user is currently on. In ITP 2.0, the referrer, if there is one, is downgraded to just the page’s origin for third party requests to domains that have been classified as possible trackers by ITP and have not received user interaction.

Previously: Safari’s Intelligent Tracking Prevention.

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