LinkedIn checks for 2953 browser extensions | Hacker News Reader

LinkedIn checks for 2953 browser extensions

github.com

534 pointsmdp239 comments

Looks like Firefox is immune.

This works by looking for web accessible resources that are provided by the extensions. For Chrome, these are are available in a webpage via the URL chrome-extension://[PACKAGE ID]/[PATH] https://developer.chrome.com/docs/extensions/reference/manif...

On Firefox, web accessible resources are available at "moz-extension://<extension-UUID>/myfile.png" <extension-UUID> is not your extension's ID. This ID is randomly generated for every browser instance. This prevents websites from fingerprinting a browser by examining the extensions it has installed. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

This is probably a naive question, but...

Doesn't the idea of swapping extension specific IDs to your browser specific extension IDs mean that instead of your browser being identifiable, you become identifiable?

I mean, it goes from "Oh they have X, Y , and Z installed" to "Oh, it's jim bob, only he has that unique set of IDs for extensions"

It's not a naive question. This comment says it's not possible to do that: https://news.ycombinator.com/item?id=46905213

Oh, it's (re)randomised upon each restart, whew, thanks for the heads up

edit: er, I think that that also suggests that I need to restart firefox more often...

The webpage would have to scan the entire UUID space to create this fingerprint, which seems unlikely.

Just have a database of UUIDs. Seems pretty trivial to generate and sort as it's only 16 bytes each.

https://libraryofbabel.info/

lol

Let's go a step further and just iterate through them on the client. I plan on having this phone well past the heat death of the universe, so this is guaranteed to finish on my hardware.

  function* uuidIterator() {
   const bytes = new Uint8Array(16); 
   while (true) {
     yield formatUUID(bytes);

     let carry = 1;
     for (let i = 15; i >= 0 && carry; i--) {
       const sum = bytes[i] + carry;
       bytes[i] = sum & 0xff;
       carry = sum > 0xff ? 1 : 0;
     }
 
     if (carry) return;
   }
 }
 
 function formatUUID(b) {
   const hex = [...b].map(x => x.toString(16).padStart(2, "0"));
   return (
     hex.slice(0, 4).join("") + "-" +
     hex.slice(4, 6).join("") + "-" +
     hex.slice(6, 8).join("") + "-" +
     hex.slice(8, 10).join("") + "-" +
     hex.slice(10, 16).join("")
   );
 }

This is free. Feel free to use it in production.

Free space heater

What license is this? Company policy says we can't use Apache licensed stuff.

"Just" have a database, and then what? I can set up a database of all UUIDs very easily, but I don't think it's helpful.

Where are you storing them, a black hole?

Fast writes, very slow reads.

All you need is basic compression, like storing the start and stop points of each block of UUIDs in the database.

Wait, you already linked to everyuuid. Do you think the server it's on uses black hole storage?

I would store them as offsets within the digits of pi.

That's actually a bright idea! Have you ever thought about applying for VC funds?

Once you deliver that, you can also think about a database of natural numbers!

But that has no moat. Anyone can generate a database of natural numbers using SOTA models.

Relevant: https://news.ycombinator.com/item?id=42342382

It exists

https://everyuuid.com/

Woosh

someone took your joke and made it real

The write-up for it is surprisingly interesting! https://eieio.games/blog/writing-down-every-uuid/#toc:entrop...

16 bytes is a lot. 4 bytes are within reach, we can scan all of them quickly, but even 8 bytes are already too much.

Kolmogorov said that computers do not help with naturally hard tasks; they raise a limit compared to what we can fo manually, but above that limit the task stays as hard is it was.

Doing it on restart makes the mitigation de facto useless. How often do you have 10, 20, 30d (or even longer) desktop uptime these days? And no one is regularly restarting their core applications when their desktop is still up.

Enjoy the fingerprinting.

Umm, I restart my PC about once a week for security and driver updates.

If you don't, you have a lot more to worry about beyond fingerprinting...

Oh and I'm on LINUX (CachyOS) mind you.

I restart my browser basically every day.

yeah I close out everything as a mental block against anything I'm working on.

I think there's a subset of people that offload memory to their browsers and that's kinda scary given how these fingerprint things work.

You just need to open so many instances and tabs in each instance that it crashes every couple days

There isn't enough energy in the solar system to count to 2^128. Now a uuid v4 number "only" has 2^122 bits of entropy. Regardless, you cannot realistically scan the uuid domain. It's not even a matter of Moore's law, it is a limitation of physics that will stand until computers are no longer made of matter.

I don't think that's the case. I have the Earth View extension installed which shows a random google earth image.

I have this set as my homepage in Firefox as moz-extension://<extension-id>/index.html, and this has not changed since installing the extension. The page still works.

Maybe, but how long are the extension ids? And if they are random, how long to scan a trillion random alphanumeric ids, to find matches?

I presume the extension knows when it wants to access resources of its own. But random javascript, doesn't.

The extension IDs are UUIDs/GUIDs, so 128 bits of entropy. No site is going to be able to successfully scan that full range.

ChatGPT told me it can be done though.

It won't disclose how, as it says it has had several users report it. And that it expects 50% of the bounty, and will use it for GPU upgrades.

And just in case the magnitude of that isn't obvious to people, that means there are 340,282,366,920,938,463,463,374,607,431,768,211,456 total possible UUIDs. Good luck.

UUIDs are 128 bit long but generally have a bit less entropy than that as they are not just a random number. Still more than enough to make enumeration infeasible though.

yes thats how browser fingerprinting works and it is impossible to defeat because there are just too many variations in monitors (relevant for fonts), simple things like user agent, etc.

And browsers trying to mitigate fingerprinting are miserable to use (fixed window size with only Arial available, etc) and probably fingerprintable anyway.

Why does the browser even allow a website to query for installed extensions? I really don't see what the point of that would be.

The website should never be able to tell what's running in my browser, or on my computer in general. The browser renders the page, maybe runs a little Javascript, but there's no reason why it should be able to query anything about my environment.

I wonder how much stuff would break if the Chrome sandboxing was extended to preventing access to chrome-extension:// from Javascript loaded of random websites.

And they said that using a browser with sub-5% market share would cause us to miss out on the latest and greatest in web technology!

chrome was made by ex-firefox devs, chrome is still not as good!

The latest and greatest is not great for you, but for them.

The real friction in browser hopping isn't features — it's keeping your workflow portable. Bookmarks especially. Each browser has its own sync silo (Chrome → Google, Firefox → Mozilla, Safari → iCloud).

For multi-browser setups (Firefox for fingerprint resistance, Chrome for the sites that only work there), cross-browser bookmark sync is weirdly undersolved. Xbrowsersync, marksyncr, and a few others exist but most people don't know about them.

Anecdote: yesterday i exported my bookmarks into an html file and then asked for a script that will make a webpage out of them. with a search. and favicon download from domain. better than any bookmark bar imho.

This is a great idea, thanks. I built an IPv6 only webhost in Digital Ocean a while ago as a learning exercise and it’s been sitting idle. Making a personal portal sounds like a fun project.

Checkout marksyncr.com for bookmarks

I use floccus.org to sync between Chrome and Zen browser, works flawlessly! It wasn't that difficut to find, once I had the two browser setup (as in the end I refufsed to fully switch to Zen), just searched extensions, and setup this up in a minute. It also syncs to google drive and bunch of 3rd party bookmark apps.

Anecdotally, I sometimes notice my computer fan spinning ferociously... it's almost always because I have left a firefox tab with linkedin open somewhere.

Are they bit coin mining or are they just incompetent?

Considering the app was a battery catastrophe I’m confident in the latter, even if your question could be read as rhetorical.

Judging from GP's description of how extension IDs work in Firefox, I wouldn't be surprised if LinkedIn were trying to brute-force those UUIDs!

If the two are indeed "Linked", I see a case for users-first browsers to show system metrics right along the page.

Maybe it's trying (and failing) to access your browser extensions? In a loop?

I've noticed similar issues with the web version of MS Teams.

You can actually see what tabs are hogging CPU by pressing SHIFT-ESC to open the task manager (about:processes) inside Firefox.

It’s probably some feature they sell to recruiters to grab your attention. :)

It's ok, they can fingerprint you for using Firefox.

Yeah, but they don't know which specific one of Firefox's last dozen users I am.

Though LinkedIn in Firefox with uBlock Origin allowing just enough (not sure if that's relevant, just haven't run it without) does not last long without rocketing CPU & memory usage, fan spinning up, etc. (ime, anyway)

In my case LinkedIn consistently crashes Firefox the first time I navigate there on a given day. After I restart FF, all is fine.

Yes, is it now?

    https://fingerprint.com/
    https://coveryourtracks.eff.org/
    https://abrahamjuliot.github.io/creepjs/

I don't have Firefox or another browser installed right now, but the last time I checked, every browser was detected, especially on the first link.

Further, When I used Tor, a few sites, like Google, showed me Captchas for a while afterward, when using my _normal_ browser.

Further I heard that sites like PayPal are giving me black karma when I try to avoid Fingerprinting by using e.g. Tor.

I actually don't even care too much if they try to detect, that I am the X from last time.

The issue is them selling the data, or using it in unrelated locations, or trying to detect me as a person. And their programmers are not enforced and rewarded when they report such behavior to law agencies / the public. And the law is not punishing it.

Skimming the list, looks like most extensions are for scraping or automating LinkedIn usage. Not surprising as there's money to be made with LinkedIn data. Scraping was a problem when I worked there, the abuse teams built some reasonably sophisticated detection & prevention, and it was a constant battle.

Wont someone think of poor little LinkedIn, a subsidiary of one of the largest data brokers in the world?

Why frame what you are trying to say like that? Businesses of all sizes deserve the ability to protect their businesses from abuse.

I think they framed it this way because they don't consider scraping abuse (to be fair, neither do I, as long as it doesn't overload the site). Botting accounts for spam is clear abuse, however, so that's fair game.

No, I consider all data collection and scraping egregious. From that perspective, LinkedIn is hypocritical when Microsoft discloses every filesystem search I do locally to bing.

Are you not scraping a site with your eyeballs when you view a site?

By that logic I can charge you for looking at me.

I agree. Maybe that logic (which is your logic) isn't very good.

You’re just making yourself look dumb by drawing invalid comparisons and an inaccurate understanding of my logic.

The big social media businesses deserve a Teddy Roosevelt character swooping in and busting their trusts, forcing them to play ball with others even if it destroys their moats. Boo hoo! Good riddance. World's tiniest violin.

This is a popular position across the aisle. Here's hoping the next guy can't be bought, or at least asks for more than a $400M tacky gold ballroom!

We enjoy the fruits of an LLM or two from time to time, derived from hoards of ill gotten data. Linkedin has the resourses to attempt to block scraping, but even at the resource scale of LI I doubt the effort is effective.

I am not denying that scraping is useful. If it wasn't people wouldn't do it. But if the site rules say you aren't allowed to scrape, then I don't think people should be hostile towards the people enforcing the rules.

Well, they can try to enforce the rules; that's perfectly fair. At the same time, there are many methods of "trying" which I would not consider valid or acceptable ones. "Enforcing the rules" does not give a carte blanche right to snoop and do "whatever's necessary." Sony tried that with their CD rootkits and got multiple lawsuits.

Do they respect my data? Why do they get to track me across sites when I clearly don't want them to but someone can't scrape their data when they don't want them to. Why should big companies get the pass but individuals not? They clearly consider internet traffic fair game and are invasive and abusive about it so it is not only fair to be invasive and abusive back, it is self defense at this point.

They don’t need to track your web browser when they’re owned by Microsoft, because they track every action at a lower level.

What lower level? Microsoft owns internet?

The operating system. For example see the Windows 11 screenshot debacle/scandal.

Are you talking about Recall, which got such huge negative press they delayed it a year and added a clear opt-in? And never sent anything off the device itself?

If anyone has evidence of constant tracking and reporting then please share it.

Well, I won't touch Windows 11 with a ten feet pole and I don't know if what I am referring to is called "Recall". Not that much into the MS terminology. I also read about Windows 11 having all kinds of shenanigans to suddenly upload data into onedrive. Wouldn't be surprised, if that also included screenshots, or could "accidentally" lead to that happening. Screenshotting every few seconds is unacceptable even if it stays on the device per se. Once data exists, it has potential to leak, and we have not even started considering malware infection yet. Huge risk to people's privacy and safety online.

We can stop pretending all it alright at some point, can't we? We don't need more enshittification. Windows 11 is already a disaster, that no one wants. It already starts with its idiotic HW requirements, trying to make perfectly fine HW obsolete. $$$

There was a lot of pushback to Recall for a reasons, yes. But it's not what you described, and criticism works a lot better when it's accurate.

For suddenly putting your documents into onedrive, that's real but it started years ago in windows 10.

Weird, I don't use Windows as an OS but have linkedin. I'd believe the concern and disregard of Linkedin's concern is fair game.

Because you signed up to a set of terms and conditions saying LinkedIn can use your data in this way

I didn't want the web to turn into monolithic platforms. I abhor this status quo.

You cannot function without these enterprises, but that doesn't mean they're ideal or even ethical.

Microsoft wins because of network effects. It's impossible to compete. So I think it should be allowed to assail their monopoly here by any means. It's maximally fair for consumers and for free markets.

Ideally capitalism remains cutthroat and impossible to grow into undislodgeable titans.

Even more ideally, this would become a distributed protocol rather than a privately owned and guarded database.

No one likes paying taxes but they still do it. They could just not work and not have money and therefore not need to pay tax.

Except what you have to pay each year for the privilege of staying in "your" house.

That doesn't actually mean anything

What if I signed up before those ToS said they could use my data in this way?

Oh right, companies change ToS and EULA and "agreements" without notice, without due process, and without recourse.

I have no problem changing how I use "their" data in such situations.

> Oh right, companies change ToS and EULA and "agreements" without notice, without due process, and without recourse.

Companies change their terms of service all the time. They usually send emails about it.

I've responded to decline them a handful of times and asked for my account to be deleted. I chuckle slightly at the work it creates, but sometimes it has been easier to close an account that way.

You do realize anti-scraping measures are one way of protecting your data too?

In this context, "protecting" means the interest of linkedin who aggressively sells the data. Users that give data to linkedin are not protecting their data either way.

“They” is an in incredibly useful tool.

I'm sure there are issues with fake accounts for scraping, but the core issue is that LinkedIn considers the data valuable. LinkedIn wants to be able to sell the data, or access to it at least, and the scrapers undermine that.

They could stop all the scraping by providing a downloadable data bundle like Wikipedia.

LLMs scrape Wikipedia all the time, or at least attempt to.

The data bundle doesn't help that at all.

That's true, the normal scraping would still happen, but it would eliminate this side business of trying to re-sell LinkedIn's data.

thinking more about, I don't think its a terrible thing that they prevent scraping. Their listings are already suffering from being flooded with garbage applications and having to sift through tons of noise. allowing scraping would just amplify that and make the platform almost entirely worthless.

I "scrape" linkedin in a roundabout way for personal use, and really what Ive found is that i should just maybee not bother at all. I can't get through the noise even when im applying at places that heavily match my skillset, and just get automated rejection emails.

Yes, until it becomes abusive and malignly affects innocents.

When they scrape, it’s innovation. When you scrape, it’s a felony.

the abuse>using the information they publish to the public

this exchange -- obvious critical / perhaps insurrection speech versus a stable voice of business economics -- should be within the purview of an orderly and predictable legal environment. BUT things moved quickly in the phone battles. Some people say that the legal system has never caught up to the data brokering, and in fact the surveillance state grew by leaps and bounds.

So, reasonable people may disagree. This is a fine place to mention it .. what if individual profiles built at LinkedIn are being combined with illegitimate and even directly illegal surveillance data and sold daily? Everyone stand up and salute when LinkedIn walks in the room? there has to be legal and direct ways to deal with change, and enforcement to complete an orderly and predictable economic marketplace.

>BUT things moved quickly in the phone battles. Some people say that the legal system has never caught up to the data brokering, and in fact the surveillance state grew by leaps and bounds.

Partially by discrepancy in how responsive you can be or comprehensive you must be to win the next round of cat-and-mouse, and partially because a private/corporate surveillance apparatus is useful to a government that might otherwise be hampered by constitutional bounds.

What is abuse? Is it anything that reduces my profit margin? Or is it anything that makes the world a worse place? The Flock CEO called Deflock terrorism, is he right?

I mean, regardless of who they are or even if you don’t like what LinkedIn does themselves with the data people have given them, the random third parties with the extensions don’t additionally deserve to just grab all that data too, do they?

Surely they do! The data is in the public internets, aren't they?

They'd put Widevine or PlayReady DRM on the website if they could, I'm sure.

why can't they?

because they're only for video files?

Eh. I worked at a company which made an extension which scraped LinkedIn. We provided a service to recruiters, who would start a hiring process by putting candidates into our system.

The recruiters all had LinkedIn paid accounts, and could access all of this data on the web. We made a browser extension so they wouldn’t need to do any manual data entry. Recruiters loved the extension because it saved them time.

I think it was a legitimate use. We were making LinkedIn more useful to some of their actual customers (recruiters) by adding a somewhat cursed api integration via a chrome extension. Forcing recruiters to copy and paste did’t help anyone. Our extension only grabbed content on the page the recruiter had open. It was purely read only and scoped by the user.

Doesn't sound like your operation was particularly questionable, but I can imagine there must be some of those 3,000 extensions where the data flow isn't just "DOM -> End User" but more of a "Dom -> Cloud Server -> ??? -> Profit!" with perhaps a little detour where the end user gets some value too as a hook to justify the extension's existence.

I started their but it felt like a dodgy way (as it could be seen to be illegal). We then just went aloffical and went through Google search API’s with LinkedIn as the target. Worked a treat and was cheaper than recruiter!!!

So when pay the highest scraper, it’s ok! Same data, different manner.

I say the same thing about my start menu sending every action I perform to bing.

from the code doesn't look like they do anything if they have a match, they just save all the results to a csv for fingerprinting?

"The code" here you're referring to (fetch_extension_names.js[1]) isn't and doesn't claim to be LinkedIn's fingerprinting code. It's a scraper that the researcher behind this repo wrote themselves in order to create the CSV of the data that they're publishing here.

LinkedIn's fingerprinting code, as the README explains, is found in fingerprint.js[2], which embeds a big JSON literal with the IDs of the extensions it probes for. (Sickeningly enough, this data starts about two-thirds of the way through the file* and isn't the culprit behind the bulk of its 2.15 MB size…)

* On line 34394; the one starting:

    const r = [{
                id: "aacbpggdjcblgnmgjgpkpddliddineni",
                file: "sidebar.html"

1. <https://github.com/mdp/linkedin-extension-fingerprinting/blo...>

2. <https://github.com/mdp/linkedin-extension-fingerprinting/blo...>

thanks, my fault for not reading the read me and just doing a quick read of the code.

In order to create the data source that LinkedIn's extension-fingerprinting relies on to work, someone (at LinkedIn*?) almost certainly violated the Chrome Web Store TOS—by (perversely*) scraping it.

* if LinkedIn didn't get it from an existing data source

3000 extensions is few enough that a small team could download each extension manually over a few months. You don't need to scrape at all.

In the first place, no one said they needed to, only that they probably did.

Secondly, it's not "3000 extensions". They didn't somehow magically divine that the 2953 (+/-47) extensions we see here were the ones that they needed to download in order to be able to exploit the content-accessible resources described in their extension manifest. They looked at a much larger set, and it got filtered down to these 2953 that satisfied the necessary criteria.

Lol no, did you even read the list? You could pay someone to just search "LinkedIn" and "talent" and "recruiting" on the chrome web store and download each extension. It's probably harder to automate this than it is to do it manually. This is something you could develop in an afternoon and pay a small team of people to do for pennies on the dollar. Even ten thousand extensions is nothing. Spread that over years and this is trivial.

For someone choosing to be so obnoxiously condescending, you are excruciatingly stupid.

Programmers don't appreciate the fact that you can just violate terms of service. You can just do it. It's okay. The police won't come after you. Usually.

Indeed. I read a lot of comments like these one you are responding on HN. It seems like there is a type of person who thinks that writing down what their rules are has some magical power.

“This isn’t what it was intended for”. Who cares?

A long long time ago in a galaxy far far away I would encounter warnings on pirating websites saying “If you are an FBI agent you are not allowed to continue on this site”. Imagine their utter disbelief and shock if they were to be arrested by an FBI agent that clicked past the warning anyway.

I agree is must be programmers as a type that like rules a lot and, they think, what a perfect world it could be if people would follow them.

I'd ask who you think you have me confused for or where you got that quote from, but I know how little it matters insofar as getting you to recognize whatever delusion led to your comment.

I am sorry, I wasn't reacting to you I was reacting to the commenter who said:

"Programmers don't appreciate the fact that you can just violate terms of service."

> comments like these one you are responding

That's my comment.

I think the point is more "in order to prevent people from scraping their site, which is against their ToS, they scraped some other site, against its ToS".

Read "in order to have more money, I did things that caused other people to have less money"

When someone who sees the world through a lens of morality notices somebody operating without morality, it is startling.

And it deserves a call out! The benefits to being so cynical that you’re numb to it come with a lot of tradeoffs

a problem for linkedin != "a problem". The real problem for people is the back room data brokering linkedin and others do.

I had the pleasure of scraping LinkedIn for a client. Great fun.

By looking the list it seems like it is not really “sophisticated”. It is just list based on names (if there is a “email” in the name). Majority of extensions do not even ask for permissions to access linkedin.com.

Chrome is the new IE6. Google set themselves up to be the next Microsoft and is "ad friendly" in all the creepy ways because that's what Google IS an ad company. All they've contributed to security is diminishing the capability of adblockers and letting malware to do bad things to you as consumers.

He who controls the Ads, controls the Internet.

> Google set themselves up to be the next Microsoft

Google became a monopoly. All monopolies do this.

there's a step before that. Google is a pure capitalist enterprize>pure capitalism goes to monopoly>all monopolies do this.

Pure unregulated market, that doesn't guarantee free market assumptions does that. Capitalism doesn't need it. Without mechanisms that allow for the free entry/exit of competitors, fair and simultaneous access to information, preventing cartels/price fixing, .... a bunch of assumptions for perfect free market to happen, the market will tend towards monopolies due cumulative advantage (in econ. known as Matthew effect), since small advantages compound into dominance.

Imagine being the nerd that is still using Chrome in the YOL 2026.

Chrome has become much worse than IE6. Microsoft was not in the business of tracking users and selling ads back then.

It certainly doesn’t feel like I have a worse UX, as a daily chrome user.

That's because you're not aware enough of being spied on at every single step you make. The issues are now more or less invisible (the tracking being more, and the lobotomized adblockers being less)

Was.

Unfortunately, yes.

I fully agree that Chrome is spyware.

However, they do contribute to security: Chrome was first to implement Site Isolation, sandboxing too. These are essential security features for modern browsers. They are also not doing too bad with patching and security testing.

Brave feels like using Chrome. The transition was seemless even as a developer who uses the devtools. Obviously that's because it's almost the same code, but Brave is much more privacy friendly right?

Brave was found to be mostly different adware years ago I thought. It's a degoogle'd chrome essentially, but replaced with their adware instead of google's.

If you want a clean chrome, use ungoogled-chromium. Like IE6, some stuff just doesn't work in librewolf (less scummy firefox), so I use ungoogled-chromium when so, and I just don't do anything googleish on it that it latches onto google again.

I can confirm.. open up linkedIn.. hit F12 and watch the error count keep going up and up and up

Screenshots found here https://x.com/DenisGobo/status/2018334684879438150

xcancel link: https://xcancel.com/DenisGobo/status/2018334684879438150

Yikes, same happening on my PC. This is crazy, nefarious websites constantly intruding in any way they can.

I wrote an article about it a couple of months ago. I also explain why, how and a way to prevent it.

https://javascript.plainenglish.io/the-extensions-you-use-ar...

To clarify, you talk about why it's possible, not why LinkedIn is doing it, right? Or did I miss something in your article.

From the article:

> ... it is used to check for abuse (bot use)

> If you follow a LinkedIn influencer and they get banned, now you know why.

I wrote a blog post recently about the technique used by LinkedIn to do extension probing, as well as other ways to do it with less side effects

https://blog.castle.io/detecting-browser-extensions-for-bot-...

Nice write up, definitely exactly this.

Patch Firefox so navigator.webdriver is always false, then remote control it. Seems not easily detectable. You could still watch for fast input patterns...

LinkedIn has been employing a lot of strange dark patterns recently:

* Overriding scroll speed on Firefox Web. Not sure why.

* Opening a profile on mobile web, then pressing back to go to last page, takes me to the LinkedIn homepage everytime.

* One of their analytic URLs is a randomly generated path on www.linkedin.com, supposedly to make it harder to block. Regex rules on ublock origin sufficiently stop this.

Anyone know why they could be doing this?

Giving them the benefit of the doubt here obviously, I know they're in an all out war with the contact database industry. Going from websoup to agents dialing out to rent-a-human services requires different tactics.

I always assumed mobile webpage misbehavior was to force you to use the app.

It could very much be confirmation bias, but I do feel like most "please use our app" popups appear after a mobile site breaks or refuses to load something

- scroll speed - unsure of ulterior motives, but i've seen this even on some foss things. i think some people just think it looks cool/modern/"responsive"/whatever

- back - hijacking it seems fairly common on malicious/dark-pattern sites to try to trap you on them. not sure why because you can just leave and it seems it would obviously piss someone off

- analytics paths - not everyone may know about/how to use regex rules for it or may use something else that doesn't support it (the stripped down ublock for chrome? i don't know if it can or not). sites seem to do this with malicious js code as well, presumably to prevent blocking

I've been wondering why my scroll speed was off in LinkedIn, inspecting scroll-related css without finding an answer, I thought this was a bug. Anyone know what property does this? I might try to fix it with uBO scripts.

I think they want you to feel disoriented.

Why do they do all this bs and not fix the bug that happens when you insert Unicode U+202E in your name?

I've been having loads of fun with that but it's never been fixed. Anyone tagging me in a comment makes their input right-to-left unless they backspace the tag or insert newline. It also jumbles notification text because your name is concatenated to the notification static text.

You can also create an inverted link but it isn't clickable, just like other unicode links which aren't punycode-encoded on LinkedIn but aren't clickable (on the clients I've tried).

I started using Chrome at version 2 I think. It still had the 3D logo. It was such a breath of fresh air and the big innovation was running one process per tab. Firefox existed but the entire browser could (and did) hang. And IE was... well, IE.

I did have a relatively early beef with Chrome though, whcih was I couldn't completely opt out of Flash. As in, I didn't even want it installed. This turned out to be an issue because Flash turned out to be one of the earliest vectors for so-called "zombie cookies".

Fingerprinting in general has been a longstanding problem and has become more and more advanced.

Add to this that Google is, first and foremost, an advertising business and they've become increasingly hostile to ad-bloccking tech for obvious reasons.

Basically what I'm getting at is something I couldn't have imagined a decade ago where I think I really have go switch away from Chrome to something that takes privacy and security seriously so that LinkedIn can't do things like this. And I increasingly don't trust Google to do that.

I actually have more trust in Apple because they have historically been user-focused eg blocking Meta's third party cookies. But obviously Safari isn't an option because it's not cross-platform.

I'm not sure I trust the current state of Mozilla. What's the alternative? Brave? Is Opera still a thing? I honestly don't know.

What I really want is a cross-platform browser written in Rust that black-holes ads out of the box. Why Rust? Memory safety. I simply don't trust a large C/C++ code to never have buffer overruns. Memory safety has become too important.

I don't want my browser to provide information on what extensions I'm using to a site and that shouldn't be a thing I have to ask for or turn on in any way.

There's a menagerie of de-mozillaed Firefox forks.

My suggestions:

Desktop - Librewolf

Android - Ironfox

LinkedIn is the worst walled garden of all of them.

I also really don't understand why their subscription is so extremely expensive for someone who is not a recruiter.

It's already a sycophantic cesspool of corporate drones repeating mindless PR. I unfollow everyone who re"tweets" feel-good memes or corporate crap and I have very few people I follow left over :) Critical discussion doesn't exist, if I comment anything that's not 100% celebratory of so-called company successes I get blocked.

Close second: conference apps.

They infuriate me. Data harvesting machines in all ways. Incredibly user hostile.

Example: making me scroll endlessly through attendee lists. Lack of good filters. Etc. Can’t download attendee lists.

I finally lost my patience and wrote a Selenium script to page through an app and extract everything. Worked well after some initial trial and error.

Curious question: why would they check for installed extensions on one's browser?

most automations for sales and marketing use browser extensions... linkedIn wants you using their tools not 3rd party

Their own tools suck, that’s the issue.

Third–party tools don't bring money to LinkedIn, that's the issue. Rather than try to compete, much easier to force you to use their tools! Reddit did the same thing.

Easy solution is to sell a plan that explicitly allows third-party tool usage. Then they get the money and the users get the tooling LinkedIn is incapable of building themselves.

(except they won't, because they're not after money but engagement, and their built-in tools suck on purpose to maximize wasted time)

An attempt at fingerprinting, I suppose?

For a social network, more information about their users = better ad targeting. It likely gets plumbed into models to inform user profiles.

Look at the actual list. It's primarily questionable AI tools, scrapers, lead generation tools, and other plugins in that vein.

I would guess this is for rate limiting and abuse detection.

Fingerprinting. There are a few reasons you'd do it:

1. Bot prevention. If the bots don't know that you're doing this, you might have a reliable bot detector for a while. The bots will quite possibly have no extensions at all, or even better specific exact combination they always use. Noticing bots means you can block them from scraping your site or spamming your users. If you wanna be very fancy, you could provide fake data or quietly ignore the stuff they create on the site.

2. Spamming/misuse evasion. Imagine an extension called "Send Messages to everybody with a given job role at this company." LinkedIn would prefer not to allow that, probably because they'd want to sell that feature.

3. User tracking.

I wrote some automation scripts that are not triggered via browser extensions (e.g., open all my sales colleagues’ profiles and like their 4 most recent unliked posts to boost their SSI[1], which is probably the most ‘innocent’ of my use-cases). It has random sleep intervals. I’ve done this for years and never faced a ban hammer.

Wonder if with things like Moltbot taking the scene, a form of “undetectable LinkedIn automation” will start to manifest. At some point they won’t be able to distinguish between a chronically online seller adding 100 people per day with personalized messages, or an AI doing it with the same mannerisms.

[1] https://business.linkedin.com/sales-solutions/social-selling...

> The bots will quite possibly have no extensions at all

I imagine most users will also not have extensions at all, so this would not be a reliable metric to track bots. Maybe it might be hard to imagine for someone whose first thing to do after installing a web browser is to install some extensions that they absolutely can't live without (ublock origin, privacy badger, dark mode reader, noscript, vimium c, whatever). But I imagine the majority of casual users do not install any extensions or even know of its existence (Maybe besides some people using something like Grammarly, or Honey, since they aggressively advertise on Youtube).

I do agree with the rest of your reasons though, like if bots used a specific exact combinations of extensions, or if there was an extension specifically for linkedin scraping/automation they want to detect, and of course, user tracking.

Does anyone know if Brave has any defense against this like Firefox does?

It doesn't seem like Brave's fingerprinting prevention includes extensions, so on my first pass I would say no.

Good call. I did a test and on Chrome I see the spam and I also see the spam on Brave as well, so they don't seem to be any different.

> This repository documents every extension LinkedIn checks for and provides tools to identify them.

I get that the CSV lists the extensions, and the tools are provided in order to show work (mapping IDs to actual software). But how was it determined that LinkedIn checks for extensions with these IDs?

And is this relevant for non-Chrome users?

Technical writeup from a few weeks ago by a vendor that explains how LinkedIn does it, then boasts that their approach is "quieter, harder to notice, and easier to run at scale":

https://blog.castle.io/detecting-browser-extensions-for-bot-...

Looks like this has been known since 2019.

https://www.nymeria.io/blog/linkedins-war-on-email-finder-ex...

The list of extensions being scanned for are pretty clear and obvious. What is really interesting to me are the extensions _not_ being scanned for that should be.

The big one that comes to mind is "Contact Out" which is scan-able, but LinkedIn seems to pretend like it doesn't exist? Smells like a deal happened behind the scenes...

https://chromewebstore.google.com/detail/email-finder-by-con...

That extension cannot be fingerprinted by its content-accessible resources. It doesn't declare any in its manifest.

interesting to see why they don't block Claude in chrome or even this: https://chromewebstore.google.com/detail/dassi-ai-coworking-...

LinkedIn has also started sending a great deal of spam:

  A $7.5B chip merger
  Pinterest prepares layoffs
  Healthcare premiums surge
  Autodesk to cut 7% of jobs
  Ozempic keeps getting cheaper

Since the "unsubscribe" link does not lead to a working page, this seems like a trivial violation of even what laughable protections CAN-SPAM alleges to offer.

And what's with some of these? Bad mouthing employers is an odd choice for a platform that makes its money from them? Or perhaps now all the revenue is ad derived?

Another thing... they alter the localStorage & sessionStorage prototype, by wrapping the native ones with a wrapper that prevent keys that not in their whitelist from being set.

You can try this by opening devtools and setting

  localStorage.setItem('hi', 123)

I wonder if this is why the linkedin feed blocker I installed in Firefox 2 weeks ago stopped working for me within 24 hours

    cut -d',' -f2 chrome_extensions_with_names_all.csv | grep -c "AI"
    474

Only 16%!?

Reading the fingerprint.js is interesting, it's not just the thousands of extensions. It looks like it's also probing for a long list of webgl extensions, fonts, and other capabilities. There's recaptcha v3 references in there too.

Perhaps an overly aggressive attempt to block bots.

So it really is espionage at all levels.

See also: a demo page for the same technique that can enumerate many extensions installed in your browser: https://browserleaks.com/chrome

Yuck. Disgusting that extension detection is possible.

I miss when websites were, by default, there to provide me content ...

I’m probably on the list. I made a LinkedIn Redactor that allowed you to add keywords and remove posts from your thread that included such words. It’s the X feature but for LinkedIn. Anyway, got a cease and desist from those lame fucks at LI. So I removed from the chrome store but it’s still available on GitHub.

I suggest everyone take a look at the list of extensions and their names for some very important context: https://github.com/mdp/linkedin-extension-fingerprinting/blo...

I didn't find popular extensions like uBlock or other ad blockers.

The list is full of scammy looking data collection and AI tools, though. Some random names from scrolling through the list:

- LinkedGPT: ChatGPT for LinkedIn

- Apollo Scraper - Extract & Export Apollo B2B Leads

- AI Social Media Assistant

- LinkedIn Engagement Assistant

- LinkedIn Lead Magnet

- LinkedIn Extraction Tool - OutreachSheet

- Highperformr AI - Phone Number and Email Finder

- AI Agent For Jobs

These look like the kind of tools scummy recruiters and sales people use to identify targets for mass spamming. I see several AI auto-application tools in there too.

LinkedIn itself provides tools for scummy recruiters to mass spam, so this is just them protecting their business.

Also, not all of them are data collection tools. There are ad blockers listed (Hide LinkedIn Ads, SBlock - Super Ad Blocker) and just general extensions (Ground News - Bias Checker, Jigit Studio - Screen Recorder, RealEyes.ai — Detect Deepfakes Across Online Platforms, Airtable Clipper).

> I suggest everyone take a look at the list of extensions and their names for some very important context[…] I didn't find popular extensions like uBlock

Unsurprising outcome since uBlock (specifically: uBlock Origin Lite, the only version available for Chrome on the Chrome Web Store) makes itself undetectable using this method. (All of its content-accessible resources have "use_dynamic_url" set to "true" in its extension manifest.) So its absence in this data is not dispositive of any actual intent by LinkedIn to exclude it—because they couldn't have included it even if they wanted to.

const nameA = getName(a).toLowerCase(); const nameB = getName(b).toLowerCase(); return nameA.localeCompare(nameB);

const msg = createDoneMessage(); msg.style.opacity = '1';

    console.log("Extensions sorted alphabetically!");
    console.table(sortedCards.map(c => ({
        name: getName(c),
        id: c.id || '—'

Cover your tracks from EFF doesn't seem to check extensions? Are there other fingerprint tests to use?

Linkedin is such a shity wanabe HR adult day care recruiting bs platform, if it would go offline tomorrow and never came back not a single tear would be shed by any Engineer.

So every Chrome extension that wants to avoid being detected this way needs to proxy fetch() on the target site, imagining someone with a bunch of them installed having every legit HTTP request on the target site going through a big stack of proxies

why would they want this type of check? Like what could it possibly be doing for the end customer or features available?

No wonder it is so slow to load.

We live in the best timeline.

[removed]

This is a security vulnerability and should be patched. Sorry, LinkedIn.

(Alternatively extension developers can modify their extensions to block these requests!)

No kidding. I am shocked this works.

Does Firefox have a similar weakness?

I don't see any evidence of this happening in Firefox. Either it's more difficult or they just didn't bother, either way I'm happy.

Edit: Can't find much documentation on exactly how the anti-fingerprinting works, but this page implies that the browser blocks extension detection: https://support.mozilla.org/en-US/kb/trackers-and-scripts-fi...

From memory from working with these a couple of years ago:

Firefox extension asset URLs are random and long (there's a UUID in there iirc). The extension itself can discover its randomized base so that it can output its asset URLs, but webpage code can't.

It doesn't work. The person who posted the comment you're responding to has absolutely no idea what he's talking about. He confabulated the entire explanation based on a single misunderstood block of code that contains the comment «Remove " - Chrome Web Store" suffix if present» in the (local, NodeJS-powered) scraper that the person who's publishing this data themselves used to fetch extension names.

No. Firefox always randomizes the extension ID used for URLs to web accessible resources on each restart [1]. Apparently, manifest v3 extensions on Chromium can now opt into similar behavior [2].

[1]: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

[2]: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

An additional improvement added in manifest v3 in both Chromium and Firefox is that extensions can choose to expose web accessible resources to only certain websites. Previously, exposing a web accessible resource always made that resource accessible to all websites.

That's a different form of defense. The original claim in this thread was that LinkedIn's fingerprinting implementation was making cross-site requests to Chrome Web Store, and that they were reading back the response of those requests.

Firefox isn't susceptible to that, because that's not how Firefox and addons.mozilla.org work. Chrome, as it turns out, isn't susceptible to it, either, because that's also not how Chrome and the Chrome Web Store work. (And that's not what LinkedIn's fingerprinting technique does.)

(Those randomized IDs for content-accessible resources, however, do explain why the technique that LinkedIn actually uses is is a non-starter for Firefox.)

Is there no browser setting to defend against this attack? If not, there should be, versus relying on extension authors to configure or enable such a setting.

I imagine that it would require browsers to treat web requests from JS differently from those initiated by the user, specifically pretending the JS-originating requests are by logged-out or "incognito" users (by, I suppose, simply not forwarding any local credentials along, but maybe there's more to it than that).

Which would probably wreak havoc with a lot of web apps, at least requiring some kind of same-origin policy. And maybe it messes with OAuth or something. But it does seem at least feasible.

As people have said it’s not making requests to web store, that’s just part of this repository looking for what extensions it’s blocking via nodejs

Browsers already have strong protections against that sort of thing, look up the same-origin policy and CORS

I see, I was too credulous.

I'm not sure how you'd patch that. Any request that’s made from the current open tab / window is made on behalf of the user. From my point of view, it's impossible for the browser to know, if the request is legit or not.

An ideal implementation of the same origin policy would make it impossible for a site (through a fetch call or otherwise) to determine whether an extension resource exists/is installed or the site simply lacks permission to access it.

Wouldn't that mean 2900 requests from fingerprint.js??

If this is true, it's insane that this would work:

- why does CWS respond to cross-site requests?

- why is chrome sending the credentials (or equivalent) in these requests?

- why is the button enabled server-side and not via JS? Google must be confident in knowing the exact and latest state of your installed extensions enough to store it on their servers, I guess

It's not true. The person you're responding to has a habit of posting implausible-but-plausibly-plausible nonsense, and it's not how this works at all.

I made the mistake of trying to skim the code hastily before I had to leave to run an errand, and yes it turns out I was wrong, but please refrain from the personal comments, and no, I don't have any such "habit."

Wrong again. (PS: The fact that you have now replied—which automatically disables comment deletion—is the only thing that prevented my removing it just now. So great job.)

> The fact that you have now replied—which automatically disables comment deletion—is the only thing that prevented my removing it just now. So great job.

How was I supposed to know that you intended to delete it?

In any case, you may still have time to edit your comment, as I did with my erroneous root-level comment, since I can't delete that either, for the same reason.

Not interested. You also shouldn't have done that. You broke the thread—exactly what HN's no-deleting-comments-that-have-replies check was created to prevent.

Consider this: just stop being reckless.

I wrote an erroneous comment in haste, which I regret. However, this kind of thing happens countless times every day on HN. It's not unusual. Except perhaps the regret part: unlike me, many of those other commenters admit no error and express no regret.

If you truly cared about HN etiquette as much as you claim, you wouldn't post haughty hyperbole such as "Consider this: just stop being reckless" and "The person you're responding to has a habit of posting implausible-but-plausibly-plausible nonsense," which go against the HN guidelines, as you may already know. Be honest: do you actually care about the thread? Why would you care, when you ridiculed my top-level comment? Who are you trying to save the thread for, posterity? Nobody cares. The thread had already been downvoted to the bottom of the submission, and the top-level comment was misinformation, so I removed it, because no more people needed to read the misinformation or respond to it. Nothing of value was lost, and I thought my action was prudent, but in any case, the term "reckless" makes a mountain out of a molehill.

My impression is that you made a bigger deal out of this than is warranted because you appear to have some kind of strange, unexplained, preexisting grudge against me and take any minor fault as an excuse to bash me personally. I have no objection to correcting a falsehood, but please keep your personal feelings to yourself and the personal attacks out of the comments.

Nice try.

<https://www.youtube.com/watch?v=WwUswWA7cRc>

Isn't it enumerating web_accessible_resources? Below static collectFeatures(e, t) there is a mapping of extension IDs to files in the const r (Minified JS, obviously.)

Edit: Confirmed. It's not pinging the Chrome Web Store. https://blog.castle.io/detecting-browser-extensions-for-bot-...

Looks to me like LinkedIn is fetching chrome-extension://{extension id}/{known filename} and seeing if it succeeds, not pinging the web store.

Should be patched nonetheless though, that's a pretty obscene fingerprinting vector.

How do you patch it? The extensions themselves (presumably) need to access the same web accessible resources from their content scripts. How do you differentiate between some extension’s content script requesting the resource and LinkedIn requesting it?

Firefox already mitigates this by randomizing the extension path: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

    The file is then available using a URL like: moz-extension://<extension-UUID>/images/my-image.png"
    <extension-UUID> is not your extension's ID. This ID is randomly generated for every browser instance.
    This prevents websites from fingerprinting a browser by examining the extensions it has installed.

Doesn't the browser know which script it's running?

Why can't it just deny access to the specified path, except to the extension itself?

It does by default, except for the files from the extension that the extension author has explicitly designated as content-accessible. It's explained ("Using web_accessible_resources") at the other end of the link.

That’s incorrect, it’s trying to load an asset (hardcoded unique per-extension path) for each extension, there is a huge list of these in the source code: https://raw.githubusercontent.com/mdp/linkedin-extension-fin...

Setup a quick CDP connection. Have Claude Code attach and inject JS into Page.addScriptToEvaluateOnNewDocument. Loads before the page.

Typical early hooks: • fetch wrapper • XMLHttpRequest.prototype.open/send wrapper • WebSocket constructor wrapper • history.pushState/replaceState wrapper • EventTarget.addEventListener wrapper (optional, heavy) • MutationObserver for DOM diffs • Error + unhandledrejection capture

what would this do?

It increases the number of jobs at the job factory. You write it into a Chrome extension and name it 2954.

This is irrelevant to the article and discussions here. Weird copypasta bullet points too.

Looks like whatever LLM you used is not doing a very good job.

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