The headline seems pretty misleading. Here’s what seems to actually be going on:

> Every time you open LinkedIn in a Chrome-based browser, LinkedIn’s JavaScript executes a silent scan of your installed browser extensions. The scan probes for thousands of specific extensions by ID, collects the results, encrypts them, and transmits them to LinkedIn’s servers.

This does seem invasive. It also seems like what I’d expect to find in modern browser fingerprinting code. I’m not deeply familiar with what APIs are available for detecting extensions, but the fact that it scans for specific extensions sounds more like a product of an API limitation (i.e. no available getAllExtensions() or somesuch) vs. something inherently sinister (e.g. “they’re checking to see if you’re a Muslim”).

I’m certainly not endorsing it, do think it’s pretty problematic, and I’m glad it’s getting some visibility. But I do take some issue with the alarmist framing of what’s going on.

I’ve come to mostly expect this behavior from most websites that run advertising code and this is why I run ad blockers.

It does two things:

1. Do a request to `chrome-extension://<extension_id>/<file>`. It's unclear to me why this is allowed.

2. Scan the DOM, look for nodes containing "chrome-extension://" within them (for instance because they link to an internal resource)

It's pretty obvious why the second one works, and that "feels alright" - if an extension modifies the DOM, then it's going to leave traces behind that the page might be able to pick up on.

The first one is super problematic to me though, as it means that even extensions that don't interact with the page at all can be detected. It's unclear to me whether an extension can protect itself against it.

> 1. Do a request to `chrome-extension://<extension_id>/<file>`. It's unclear to me why this is allowed.

Big +1 to that.

The charitable interpretation is that this behavior is simply an oversight by Google, a pretty massive one at that, which they have been slow to correct.

The less-charitable interpretation is that it has served Google's interests to maintain this (mis)feature of its browser. Likely, Google or its partners use similar to techniques to what LinkedIn/Microsoft use.

This would be in the same vein as Google Chrome replacing ManifestV2 with ManifestV3, ostensibly for performance- and security-related purposes, when it just so happens that ManifestV3 limits the ability to block ads in Chrome… the major source of revenue for Google.

The more-fully-open-source Mozilla Firefox browser seems to have had no difficulty in recognizing the issues with static extension IDs and randomizing them since forever (https://harshityadav.in/posts/Linkedins-Fingerprinting), just as Firefox continues to support ManifestV2 and more effective ad-blocking, with no issues.