Cross domain tracking even with 3rd party cookies disabled.
Unknown
Vulnerability Details
Cross domain tracking
Default settings from Brave browser has 3rd party cookies disabled. Which I am assuming also disables 3rd part storage like IndexedDB etc. Because of this protection it is not possible for a 3rd party to track users across multiple domains.
But, Even though third-party cookies is disabled by default using Shared workers, a third-party is able to track the user across domains and websites.
REPRODUCTION STEPS
If you visit the these three pages in three tabs, you will notice that as a third-party it can learn the movement of a user across domains, even though the user has disabled 3rd party cookies.
https://cdn.cliqz.com/browser-f/fun-demo/some-random-page.html
https://cdn2.ghostery.com/browser-f/fun-demo/some-random-page.html
The third party script is being loaded from https://konarkmodi.github.io/
## Impact
Because of this protection it is not possible for a 3rd party to track users across multiple domains. The demo is not very clever, but a 3rd party with a large footprint on the web can use this to track substantial web browsing behaviour of the user.
Actions
View on HackerOneReport Stats
- Report ID: 331428
- State: Closed
- Substate: informative
- Upvotes: 2