Posted by danpinto 19 hours ago
I was expecting an ad for their product somewhere towards the end, but it wasn't there!
I do wonder though: why would this company report this vulnerability to Mozilla if their product is fingeprinting?
Isn't it better for the business (albeit unethical) to keep the vulnerability private, to differentiate from the competitors? For example, I don't see many threat actors burning their zero days through responsible disclosure!
No software wants to be fingerprinted. If it did, it would offer an API with a stable identifier. All fingerprinting is exploiting unintended behavior of the target software or hardware.
You want fingerprinting to identify low risk users to skip the inconvenient security checks.
> Most users seem to not care about ad tech/tracking
Most people don't understand that they're being tracked. The ones that do generally don't understand to what extent.
You tend to get one of two responses: surprise or apathy. When people say "what are you going to do?" They don't mean "I don't care" they mean "I feel powerless to do anything about it, so I'll convince myself to not care or think about it". Honestly, the interpretation is fairly similar for when people say "but my data isn't useful" or "so what, they sell me ads (I use an ad blocker)". Those responses are mental defenses to reduce cognitive overload.
If you don't buy my belief then reframe the question to make things more apparent. Instead asking people how they feel about Google or Meta tracking them, ask how they feel about the government or some random person. "Would you be okay if I hired a PI to follow you around all day? They'll record who you talk to, when, how long, where you go, what you do, what you say, when you sleep, and everything down to what you ate for breakfast." The number of people that are going to be okay with that will plummet. As soon as you change it from "Meta" to "some guy named Mark". You'll still get nervous jokes of "you're wasting money, I'm boring" but you think they wouldn't get upset if you actually hired a PI to do that?
The problem is people don't actually understand what's being recorded and what can be done with that information. If they did they'd be outraged because we're well beyond what 1984 proposed. In 1984 the government wasn't always watching. The premise was more about a country wide Panopticon. The government could be watching at any time. We're well past that. Not only can the government and corporations do that but they can look up historical records and some data is always being recorded.
So the reason I don't buy the argument is because 1984 is so well known. If people didn't care, no one would know about that book. The problem is people still think we're headed towards 1984 and don't realize we're 20 years into that world
Yes and no, because people still will think that when it's done at scale it's different from some stalker following YOU explicitly, and not just following everybody. Also, the mental model is "they just want to sell me something, but I can just ignore and don't buy if I'm not really interested". And especially going down this second rabbit-hole opens a whole world about consumerism that not many people are comfortable with. At the same time there are people that are totally against consumerism that should be more informed and care more about tracking and privacy; with those people it's probably easier to have that conversation.
This is exactly what I was saying - if you look at the polls, people actually tend to support things like the UK's Online Safety Act. Explaining it more does not usually result in a change of that. The difference with a PI is you're asking about them individually instead of everyone - of course they trust themselves, they just want everyone surveilled for that same feeling of confidence.
People don't care. This is demonstrably true.
Part of the problem is the misconception that the data being collected is only being used to determine which ads to show them. Companies love to frame it that way because ultimately people don't actually care that much about which ads they get shown. The more people get educated on the real world/offline uses of the data they're handing over the more they'll start to care about the tracking being done.
I joke that I'm a no-app person, because I install very few apps and I use anti tracking tech on my phone that's even hard to explain or recommend to non technical friends. I use Firefox with uMatrix and uBlock Origin and Blockada. uMatrix is effective but breaks so many sites unless one invests time in playing with the matrix. Blockada breaks many important apps (banking) less one understands whitelisting.
On what basis do you claim that software developers, who did not establish a means of for third parties to get a stable identifier, nevertheless intended that fingerprinting techniques should work?
TBF the idea that any and all fingerprinting falls under the umbrella of exploiting a vulnerability was also presented as an assertion. At least personally I think it's a rather absurd notion.
Certainly you can exploit what I would consider a vulnerability to obtain information useful for fingerprinting. But you can also assemble readily available information and I don't think that doing so is an exploit though in most cases it probably qualifies as an unfortunate oversight on the part of the software developer.
1) wanting functionality that isn't provided and working around that
and
2) restoring such functionality in the face of countermeasures
The absence of functionality isn't a clear signal of intent, while countermeasures against said functionality is.
And then there is the distinction between the intent of the software publisher and the intent of the user. There is a big ethical difference between "Mozilla doesn't want advertisers tracking their users" and "those users don't want to be tracked". If these guys want to draw the line at "if there is a signal from the user that they want privacy, we won't track them", I think that's reasonable.
> IMO you need to actually work around a technical measure intended to stop you for it to qualify as an exploit.
Even well-known vulnerabilities like SQL injection don't qualify under this definition?
The point isn't my precise wording but the underlying concept that making use of freely provided information isn't exploiting anything even if both the user and the developer are unhappy about the end result. Security boundaries are not defined post hoc by regret.
An example that comes to mind that I've seen is an anonymous app that allows for blocking users; you can programmatically block users, query all posts, and diff the sets to identify stable identities. However, the ability to block users is desired by the app developers; they just may not have intended this behavior, but there's no immediate solution to this. This is different than 'user_id' simply being returned in the API for no reason, which is a vulnerability. Then there's maybe a case of the user_id being returned in the API for some reason that MIGHT be important too, but that could be implemented another way more sensibly; this leans more towards vulnerability.
Ultimately most fingerprinting technologies use features that are intended behavior; Canvas/font rendering is useful for some web features (and the web target means you have to support a LOT of use cases), IP address/cookies/useragent obviously are useful, etc (though there's some case to be made about Google's pushing for these features as an advertising company!).
Strong disagree.
> IP address/cookies/useragent obviously are useful
Cookies are an intended tracking behavior. IP Address, as a routing address, is debatable.
> Canvas/font rendering is useful for some web features
These two are actually wonderful examples of taking web features and using them as a _side channel_ in an unintended way to derive information that can be used to track people. A better argument would be things like Language and Timezone which you could argue "The browser clearly makes these available and intends to provide this information without restriction." Using side channels to determine what fonts a user has installed... well there's an API for doing just that[0] and we (Firefox) haven't implemented it for a reason.
n.b. I am Firefox's tech lead on anti-fingerprinting so I'm kind of biased =)
[0] https://developer.mozilla.org/en-US/docs/Web/API/Local_Font_...
The thing is, technology is either enabling something or not. The exploration space might be huge, but once an exploit is found, the exploitation code / strategy / plan can trivially proceed and be shared worldwide. So you have to deal with this when you design and patch systems.
Example: preserving paths in URLs. Safari ITP aggressively removes “utm_” and other well-known querystring parameters even in links clicked from email. Well, it is trivial to embed it in a path instead, so that first-party websites can track attribution, eg for campaign perfomance or email verification links etc. In theory, Apple and Mozilla could actually play a cat-and-mouse game with links across all their users and actually remove high-entropy path segments or confuse websites so much that they give up on all attribution. Browser makers or email client makers or messenger makers could argue that users don’t want to have attribution of their link clicks tracked silently without their permission. They could then say if users really wanted, they could manually enter a code (assisted by the OS or browser) into a website, or simply provide interactive permission of being tracked after clicking a link, otherwise the website will receive some dummy results and break. Where is the line after all?
Unintended identification is less than ideal but frankly is just the nature of doing business and any number of niceties are lost by aggressively avoiding fingerprinting.
In software intentionally optimized to avoid any fingerprinting however it is a vulnerability.
The distinction being that fingerprinting in general is a less than ideal side effect that gives you a minor loss in privacy but in something like Tor Browser that fingerprinting can be life or death for a whistleblower, etc. It's the distinction between an annoyance and an execution.
In what way is collecting a record of a person's browsing history a "minor loss" of privacy. For many people, tracking everywhere they go online would easily expose the most sensitive personal information they have.
I get criticizing their business and what they do wrong, but doesn't seem right to criticizing them for doing the right thing.
Its been my experience that the general public doesn't seem to follow patterns and instead focus on which switch is toggled at any given moment for a company's ethical practices. This is the main reason why we are constantly gamed by orgs that have a big picture view of crowd psychology.
I understand where you're coming from, by the way, but sometimes the worst person you know does the right thing and it's not fair to criticize them for doing it (you could say nothing, don't have to change your opinion about them, etc). We also don't want someone to go "if I'm bad no matter what I do, then might as well make some money with this" and sell the exploit.
I hear you. I guess I just want to promote more vigilance. Looking at patterns and motives helps us stay balanced about these things IMHO.
It's not like you can't point out that they did a good deed, but that they're still in the shitty business of fingerprinting users.
Also, if people only get the stick no matter what they do, then eventually some will embrace the dark side and at least make money out of it. And that's not good for you.
Nothing wrong with pointing out hypocrisy and bullshit, but criticizing something they did right? That's not how I operate. You are, of course, free to do things differently.
And yet, they did a good thing. I will criticize everything else, but not what they did right. It doesn't mean I'll go out of my way to praise them either... if it wasn't your comment, I wouldn't have said anything at all.
(Also known as the "Copenhagen Interpretation of Ethics": https://gwern.net/doc/philosophy/ethics/2015-06-24-jai-theco... )
But your considering of all methods that enable fingerprinting as vulnerabilities is your own opinion. There are definitely measurable signals that are based on a user’s behavior, rather than data exposed by the browser itself.
Maybe because is not as serious as them and their title, made it to be? Did you read it fully?
The identifier described is not process lifetime stable, not machine stable, or profile stable, or installation stable. The article itself says it resets on a full browser restart...
So this is not a magic forever ID and not some hardware tied supercookie. Now what should we do with that title, and the authors of it?
Don't get your opsec advice from HN. Check whonix, qubes, grapheneos, kicksecure forums/wikis. Nihilist opsec, Privacyguides.
Make sure to exit Tor Browser at the end of a session. Make sure not to mix two uses in one session.
Whether they care is entirely separate.
Also, does anyone know of any researchers in the academic world focusing on this issue? We are aware that EFF has a project that used to be named after a pedophile on this subject, but we are more looking for professors at universities or pure research labs ala MSR or PARC than activists working for NGOs, however pure their praxis :-)
As privacy geeks, we have become fascinated with the topic -- it seems that while we can achieve security through extensions like noscript or ublock origin or firefox containers (our personal "holy trinity"), anonymity slips through our fingers due to fingerprinting issues. (Especially if we lump stylometry in the big bucket of "fingerprinting".)
[1] https://web.archive.org/web/20260422190706/https://fingerpri...
You bring this up like it's a well known incident, but my googling can find no evidence of it? The only reason not say the name of the project would be if it's common knowledge, but it's not?
ChatGPT research reckons you're making it up, and I'd be curious if you have evidence to the contrary?
So what happened here is basically... AI told you that something that made you suspicious because you have zero subject matter expertise is suspect?
I'm not really sure how to react to someone who has a robot affirm their anxieties other than to stand by my previous statements and give a polite pointer at some terms to look up on Wikipedia rather than feed into a clanker.
You said it was “named after a pedophile”, that is wrong
>>The word panopticon derives from the Greek word for "all seeing" – panoptes.
The concept was invented by Jeremy Bentham, who died before Foucault was born.
Interesting that you named your HN account after a famous homophobe.
i also like anonbib as a central repo for interesting work.
Why don't browsers make it like phones where the server (app) has to be granted permission to access stuff?
A user agent that says the browser's version? Reasonable enough.
Being able to ask for fonts, if the system has them? Difficult to have font support without that.
Getting the user's timezone, language and keyboard layout? Reasonable.
The size of the screen, and the size of the browser window? Difficult to lay things out without that.
Of course a video or audio player needs to know which video formats your browser supports - how else to provide the right video?
Obviously javascript can get the time, and it's trivial to figure out the system's clock error by comparing that to the time on a server.
Before you know it, almost every browser is uniquely identifiable.
User agents as a concept are rather poorly thought out across the board and not all that useful but persist because that's just how technical cruft is.
Fonts should be provided by the website; if not provided the choice should take the form of a spec sent by the website including line height, sarifs or not, monospace or not, etc. There's little to no excuse for the current font situation IMO beyond poor design decisions that became heavily entrenched.
Timezone and other obviously private metadata should never be shared without the user explicitly granting permission on a case by case basis. The status quo here is completely inexcusable as is the continued failure to fix the problem.
Size of the physical screen should never be exposed under any circumstances. The current size of the browser window is reasonable on its face but now that fingerprinting is understood to be an issue should always be heavily letterboxed unless the user consents to sharing the exact value.
Video formats should be provided by the website as a list of offerings and the browser should respond with a choice; the user could optionally intervene. There's no reason to expose the full capabilities to a remote service.
Querying the current time should be gated behind an explicit permission. There's almost never a need for it. However from a fingerprinting perspective you also have to worry about correlating the rate of clock skew across clients. That can be solved by gating access to high resolution time counters behind an explicit permission as (once again) the vast majority of services have no legitimate use for such functionality.
Now we have actual criminal organizations and other real bad actors.
I'm sure we can come up with something better than advertise our whole local computing platform on every HTTP request.
All these things should be opt-in and like blocked by GDPR.
No applications. No mail. No need for cookies.
I can use a "regular" browser for more enhanced stuff. But for simple content consumption, we can just have a "dumb" browser that can't do much.
> A user agent that says the browser's version? Reasonable enough.
No user agent. I'm guessing it will need it for JavaScript or HTML features, and dynamically update if using an old browser, but let's just not supply a user agent and let it be the reader's burden to have a reasonably decent browser.
> Being able to ask for fonts, if the system has them? Difficult to have font support without that.
What's the fallback if the system doesn't have them?
> Getting the user's timezone, language and keyboard layout? Reasonable.
Keyboard layout is irrelevant for viewing content. For timezone and language: Yeah, I can see the use cases, but these are in a small minority. Let there be a popup when requested, and the user can specify the timezone/language as requested.
> The size of the screen, and the size of the browser window? Difficult to lay things out without that.
Let's let this new browser return only from a (small) discrete set of sizes. It will pick the size closest to the actual browser window size and send that.
> Of course a video or audio player needs to know which video formats your browser supports - how else to provide the right video?
Same answer as user agent. Either let the user pick from a selection of video formats, or just hard code a reasonable one and put the onus on the user to have a browser that supports it.
> Obviously javascript can get the time, and it's trivial to figure out the system's clock error by comparing that to the time on a server.
This hypothetical browser could just not send the time :-) For 99% of content consumption, this function is not needed.
What I'm describing should be part of "Private mode". Or browsers should have an "Ultra-private" mode that is the above. If it's too complex/risky maintaining it all in one codebase ... fine. Just have a separate browser.
Right now, if I built such a browser, I'm sure a lot of sites meant for content would break. But in my fantasy world, using "Ultra-private" would be the default, and people who make sites will target them first.
I think much of the complexity in making a web browser is all the "other" stuff. Being able to run apps, cookie/privacy management, etc.
If 100 people are using that browser, how will they know which one is me?
> How browsers render SVGs can be used for fingerprinting (even the underlying OS affects this, and I assume you'll want to see those)
Can you provide details on this? And how will they know which OS I'm using (through SVG rendering...)? The UserAgent definitely should not send the OS.
> combine with ISP from IP address
That's already provided whether I use Private mode or not, correct? I can always use a VPN.
No support for forms. The browser is meant for content consumption. Not for interaction/creation.
One could argue that any JS capabilities to do network requests (including dynamically rendering content) would be disallowed.
Yes, I know, this is going pre-Web 2.0.
Yes, of course, most current sites won't work in that model. But I'll also say: Most current content sites don't need these capabilities. They have them because they know the browser supports them.
Again - a fantasy. I know only a few people will use it. I know that won't be enough to change web behavior. It would be nice, though, if sites carried a badge to indicate they conform to all of the above.
What you want exists, have at it
"Web applications use it for offline support, caching, session state, and other local storage needs"
This use case is completely orthogonal to what my browser is meant to do. My browser would not have a concept of local storage.
The premise of starting with a modern browser and stripping away features to get privacy is flawed - it's always vulnerable to these types of things. I'm going the opposite route: Only add features if they cannot be exploited for monitoring.
thankfully i think traditional web surfing is probably going to die out in the next 10 years, and progressively decline a lot much sooner than that as people start to interact with AI rather than browsers (or any software for that matter).
my feed of hackernews is going to be my AI agent giving it to me in plain text very soon, and soon after that i will probably never visit the internet again because it will be impossible to know what's real and fake
as a millennial it will be interesting to experience the full cycle of being born when nothing was online, to everything being online, to then again being entirely offline by the time i'm older
Wait for the advent of local agents running on local models (for privacy) followed by techniques to fingerprint agents, followed by techniques to infer query parameters based on agent behavior. I wish I was joking but it seems all too plausible.
Browsers do not "generate" fingerprints. They expose data that can be used to fingerprint users. You cannot "randomize" this; even if you were to return random values for, say, user screen size, with various visual side effects, it would just be another signal to fingerprint: "Oh, your browser is returning random values? Must be a Tor browser user".
You'd have to fingerprint the browser first to determine that the "random values" were indeed coming from it.
When i use Resist Fingerprinting my main issue is the timezone being set to UTC. most of the other stuff it does never causes issues. I guess sometimes sites need to read the canvas, but theres a permission box that allows that when needed. I wish there was a similar permission box for timezone.
The only other drawback to the "resist fingerprinting" option is you will encounter cloudflares' captcha checkbox everywhere and all of the time :(
Apps have access to inconceivable amounts of identifiers and device characteristics, even on the well protected systems without Google Play services.
Like Android phones perhaps? Unfortunate Apple gives very little granular control.
But most ROMs don't allow controls for WiFi, Cell data, Phone ID, Phone number, User ID, local storage, etc...
And since browsers rival OSes for complexity (they are basically OSes in their own right already), any part of the system can be inadvertently exposed and exploited.
> In Firefox Private Browsing mode, the identifier can also persist after all private windows are closed, as long as the Firefox process remains running. In Tor Browser, the stable identifier persists even through the "New Identity" feature, which is designed to be a full reset that clears cookies and browser history and uses new Tor circuits.
1. Website fingerprints the browser, stores a cookie with an ID and a fingerprint.
2. During the next session, it fingerprints again and compares with the cookie. If fingerprint changed, notify server about old and new fingerprint.
Assume the same.
>The idea is to amass as much information as possible
Reminded, from 2012: https://www.wired.com/2012/03/ff-nsadatacenter/
Hmm, I'm a little confused, since in 2021 Mozilla released experimental one-process-per-site:
> This fundamental redesign of Firefox’s Security architecture extends current security mechanisms by creating operating system process-level boundaries for all sites loaded in Firefox for Desktop
https://blog.mozilla.org/security/2021/05/18/introducing-sit...
Perhaps that is not fully released?
Or perhaps it is, but IndexedDB happens to live outside of that isolation?
If so, cool!
JS also dramatically improves security. TBB is stuck in a 90s mindset about privacy, as if Firefox exploits were not dime a dozen. Especially with AI making FF exploits more available, we can expect many tor sites to be actively attacking their visitors.
Tor endpoints are pretty easy to identify, there are plenty of handy databases for that, using it to begin with increases your uniqueness. If noscript was set to strictly disallow javascript by default, that decreases the degree to which it increases your signature relative to the baseline of using tor.
Then we have to account for the simple fact that many, many fingerprinting techniques rely on javascript, so taking them out of the picture reduces the unique identity that can be gleaned.
Are we absolutely, positively sure that the tradeoff is worth it? Without a strict repeatable measurement, I think I'm highly skeptical about whether or not a default of "allow" is a net boon to hiding your identity. I remember the rationale about the switch mostly being directed towards "most of the web is broken otherwise and that's bad."
If TBB changed to js off by default that signal would be less evident, and also, fingerprinting would be harder.
How so?
Tor Browser also doesn't spoof navigator.platform at all for some reason, so sites can still see when you use Linux, even if the User-Agent is spoofing Windows.
I've heard a handful of people say this but are there examples of what I would imagine would have to be server-side fingerprinting and the granularity? Since most fingerprinting I'm aware of is client-side, running via JS. While I expect server-side checks to be limited to things like which resources haven't be loaded by a particular user and anything else normally available via server logs either way, which could limit the pool but I wonder how effective in terms of tracking uniqueness across sites.
https://fingerprint.com/blog/disabling-javascript-wont-stop-...
There is also a method of fingerprinting using the favicon: https://github.com/jonasstrehle/supercookie
We're talking about users of the Tor browser, and I'd be very surprised if this was the case (that a majority keep JS turned on)
Basically every Tor guide (heh) tells you to turn it off because it's a huge vector for all types of attacks. Most onion sites have captcha systems that work without JS too which would indicate that they expect a majority to have it disabled.
Why is this global keyed only by the database name string in the first place?
The post mentions a generated UUID, why not use that instead, and have a per-origin mapping of database names to UUID somewhere? Or even just have separate hash-tables for each origin? Seems like a cleaner fix to me compared to sorting (imo, though admittedly, more of a complex fix with architectural changes)
Seems to me that having a global hashtable that shares information from all origins is asking for trouble, though I'm sure there is a good explanation for this (performance, historical reasons, some benefits of this architecture I'm not aware of, etc.).