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Vulnerability allows cross-browser tracking in Chrome, Firefox, Safari, and Tor

fingerprintjs.com

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Re: Vulnerability allows cross-browser tracking in Chrome, Firefox, Safari, and Tor

#2

Post by bronzeage »

Looking at their product, I wonder how many of these kind of vulnerabilities are still open and exploited by them. Wouldn't make much sense for them to burn such a useful vulnerability which is required for their product unless they had something better.

Re: Vulnerability allows cross-browser tracking in Chrome, Firefox, Safari, and Tor

#3

Post by harikb »

> Profiling based on installed apps

> most browsers have safety mechanisms in place designed to prevent such exploits. Weaknesses in these safety mechanisms are what makes this vulnerability possible.

> By specification, extensions need to be able to open custom URLs, such as mailto: links, without confirmation dialogs. The scheme flood protection conflicts with extension policies so there is a loophole that resets this flag every time any extension is triggered

If true, this sounds worse revelation than the exploit itself. Disabling a flag temporarily sounds bad, regardless of whether a vulnerability exists.

Re: Vulnerability allows cross-browser tracking in Chrome, Firefox, Safari, and Tor

#4

Post by harikb »

bronzeage wrote: post #2

Looking at their product, I wonder how many of these kind of vulnerabilities are still open and exploited by them. Wouldn't make much sense for them to burn such a useful vulnerability which is required for their product unless they had something better.

> DISCLAIMER: FingerprintJS does not use this vulnerability in our products and does not provide third-party tracking services

Re: Vulnerability allows cross-browser tracking in Chrome, Firefox, Safari, and Tor

#6

Post by buggeryorkshire »

I've no idea whether it works, but they misidentified many apps I don't have installed (Postman, Express VPN, Notion, Figma, Hotspot Shield)

It does do the popup for VSCode asking if I want to open links there, which I do have installed.

Re: Vulnerability allows cross-browser tracking in Chrome, Firefox, Safari, and Tor

#9

Post by nimbius »

>By opening a popup window with a custom URL scheme and checking if its document is available from JavaScript code, you can detect if the application is installed on the device.

in FF, unless im mistaken this assumes the user clicks anything except cancel on the popup. bug for reference and comment. https://bugzilla.mozilla.org/show_bug.cgi?id=1711084

further from the github:

> the basic concept is the same. It works by asking the browser to show a confirmation dialog in a popup window. Then the JavaScript code can detect if a popup has just been opened and detect the presence of an application based on that.

so...we seem to be relying on the honor system with the user? Can anyone clarify?

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