Browserprint: are you uniquely identifiable?
browserprint.info
browserprint.info
* https://addons.mozilla.org/en-us/firefox/addon/random-agent-...
Turning everything off, or disabling plugins is a unique data point in itself; I am not sure we'd want to avoid leaking our plugin configuration as if that is the default, we are then a very unique data point. Instead, we would have to know what values are common, then report those to servers.
Edit: Also, the cited Firefox plugin doesn't seem to spoof the client's display resolution correctly[1]. With such plugins, I can imagine our profiles become increasingly unique, as it may present potentially numerous combinations of metrics to servers that are not typical in the wild.
Check this: https://github.com/Mechazawa/Firefox-plugin-enum-disable (works in Chromium via Tampermonkey and Firefox via Greasemonkey)
EDIT: argh you wrote 'Plugins' not Addons...
There are some things like Flash that should identify themselves, but those are few and far between, and the check should be feature specific and handled by the plugin.
Allowing every site to build a profile based on plugins [that is: a) fingerprint, and b) profile based on the plugins I use] is just an egregious violation of privacy.
At the very least, if there is some reason to expose browsers, let it be configurable.
Also, font testing should be made expensive [eg, one check per second]. Check if we have font "scrabble", OK, but not get list of all fonts.
There is no way to prevent "fingerprinting", infact what you suggest seems to indicate that you are thinking about it the wrong way. You can disable these plugins but that creates a fingerprint on it's own, if you only accept HTML (no HTML5 because it's also "evil") and no javascript well then you are a more unique fingerprint than your vanilla Chrome with Flash, PDF, and a few WebM and DRM plugins. The only effective way of disabling fingerprinting is make all browsers identical, and more importantly all hardware and software configurations that those browsers operate in also identical.
You also need to understand the value of each fingerprint if you look at https://panopticlick.eff.org/ for example then most of the fingerprints produced are useless, half of them are shared between 30-80% of all browsers. The most unique one was the HTTP_ACCEPT Headers in my case which is unique for one out of ~1400 browsers so that is something I can now use to see if this is something that can be fixed. The plugin fingerprint in my case is 1 out of 48 browsers, that is not unique in any case and from what I've tested every latest Chrome install on Windows 10 without any additional content plugins (e.g. Java) has the same fingerprint.
If you've got 4 metrics each of which slice about "1 in 50" then taking the combination you've got a metric that is unique between 1 in 50 and 1 in 6.25 million (depending on correlation).
The "fingerprint" is all that information put together, not each taken in isolation.
If I spin up 10 new Windows 10 machines install Chrome on them I would get the same fingerprints, oddly enough they would be identical to the fingerprints I'm getting on my own machine since I don't have any plugins installed (I do have multiple extensions).
The only real change in the fingerprint I've seen so far from my own internal testing is the screen resolution, and WebGL fingerprint (Intel/NVIDIA seem to produce a pretty identical one, AMD differs a bit).
However the main point i was trying to get across is that while trying to minimize your fingerprint or exposure you create your own unique fingerprint in the process.
For example using adblockers these addons can easily leak not only which adblocker you are using but which lists / filters you have enabled, if you are a non-English native and you are using a localized list that exposes a lot of information.
Addons / extensions that block things like HTML5 Canvas also leave a fingerprint - you run a modern browser by all accounts but don't support Canvas? whelp you are upto something!
Same goes with WebGL and many other plugins/vectors.
The problem here is that content delivery relies on the browser being interrogatable for certain information, if that information is not correct then the content will not be displayed properly (which on it's own can be detected), we want to move on from Flash, we want to move one from addons and plugins into more native stuff but this came at a cost of platforms being more unique and diverse which allows you to generate a more unique fingerprint. Creating a browser that generates random fingerprints also won't really help, unless everyone uses it you would again stand out of the crowd even more.
That said however without specific targeted exploitation I have not yet seen a tool nor I managed to make one that creates a good fingerprint that can be easily used to identify a browser rather than just classify it and the platform it's running on.
There's no way of doing that without making the whole browser really slow. Browsers don't expose any way to get a list of fonts: all you can do is try drawing some text with a given font "scrabble" and then see if it draws with different metrics to the fallback font. Therefore, you'd have to make every new font used on a page take a second before it got drawn, practically forcing every page to use a single font.
Just a guess: perhaps because sometimes, those plugins need to be interacted with from within javascript?
I pass the first three tests here, but fingerprinting does the trick. About one in 50k browsers has the same fonts as me. About one in 30k browsers have the same addons and plugins. I bet those two don't overlap. Then there are several other variables like language that narrow it down if that is still needed.
They could try to explain how to make a browser not uniquely identifiable however. What browser configuration is not unique? What do I have to do to get that?
> Browserprint is a free open source project designed to provide the same and better functionality as the original Panopticlick.
(Though I'm not sure exactly what they've done to make it better..but the hat tip is there at least!)
But speaking of javascript, how many of the fingerprinting checks will not be possible if js is turned off? I could imagine that definitely all screen-related stuff is immediately killed.
Is there some Firefox extension I can use to spoof my font list to some subset of my existing font list to conform with some widely used system default? I do have some custom fonts installed, but I'd prefer random websites I visit to not know about them if possible.
Also, the way plugins are handled in Firefox has always bothered me quite a bit. I can disable them, but not remove them. What gives?
'What is your screen resolution? What HTML5 features do you support? Do you have this font/plugin?'
Bar giving up all those facilities, the best you can do is ask and hope they comply....
For instance, you can change your user agent and headers to some generic Windows Chrome one but a savvy tracker will fingerprint your TCP connection and realise you are actually on a Mac, and that can be used as a further source of entropy to better identify you.
I've spent more time than is healthy looking into ways to uniquely identify devices on the internet. While the company I was working for was always on the safe side in terms of privacy, the more blackhat methods can be useful in collaborating with law enforcement to deanonimise Tor users (think pedophiles, not drugs)
Tor Browser devs have in turn been really good at hardening fingerprinting attack vectors related to it (and rightly so, browsers don't rape people — people rape people) but unless you're super paranoid it's not a great experience for the average user.
I think a better solution will come (at least in the EU) from the proposal to extend cookie law to any kind of fingerprinting (regardless of storage), which takes use case in account and can be enforced through big fines.
Couldn't this be worked around by reporting random values every time?
It's very hard to get away completely... even with Tor, if you are the only person who uses Tor to visit a certain site you are as trackable as anyone else for that site.
It would be interesting to see some reports on that question. Of course, the Law would never abide such accountability, but one can dream...
I don't know about accountability, but we provided support in a proactive way and never more than we were comfortable with (no carte blanche access to data for LEOs, etc.)
The law even has exemptions for security-related applications — your bank already fingerprints your device and uses it as a first line of protection against card theft.
yep, pretty unique