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>the Mullvad Browser applies a "hide-in-the-crowd" approach to online privacy by creating a similar fingerprint for all of its users. The browser's 'out-of-the-

>the Mullvad Browser applies a "hide-in-the-crowd" approach to online privacy by creating a similar fingerprint for all of its users. The browser's 'out-of-the-box' configurations and settings will mask many parameters and features commonly used to extract information from a person's device that can make them identifiable, including fonts, rendered content, and several hardware APIs. What does masking specifically mean? Is it returning pre-canned responses to those queries that match non mullvad browser users. Because otherwise the absence of these APIs basically fingerprints the user to the Mullvad Browser which, realistically, will always be a small fraction of total browser sessions.

em-bee 3y ago
considering the difference between the words mask and hide, i would assume it's replacing them with canned values.
- reaperducer 3y ago
  Hopefully the values rotate randomly through a common set of values, rather than just making everyone Windows 11/Chrome.
  - smegsicle 3y ago
    the 'scanner darkly' method, i think xxxterm used to do that probably more annoying to fingerprint in general, but its own signal in another way
    - em-bee 3y ago
      well, each individual browser should not rotate the values to often, every few weeks or months maybe, if at all, or when sessions are cleared. or they could differ per site. but across all browser instances a statistical distribution of values that is similar to the existing distribution would help to ensure that no particular value stands out. given that it is firefox this should also mean that only average firefox values should be used because the browser itself can be detected through checking feature differences which can't be masked as easily.
RamRodification 3y ago
"a similar fingerprint for all of its users", to me, makes it sound like they accept the fact that users will be fingerpritable as Mullvad Browser users (but not more precise than that). Actually, which other crowd could they even be referring to with "hide-in-the-crowd"?
- mpixel 3y ago
  let's say windows 11 users who use google chrome
  - ISO-morphism 3y ago
    Not sure if you're being sarcastic or not, but Windows 11 users who use Google chrome are only really a crowd at the User Agent string level. Chrome allows much deeper fingerprinting.
  - Bu9818 3y ago
    It's going to be extremely difficult to imitate another browser like that, especially one of a different codebase. Chrome is extremely fingerprintable too.
Sakos 3y ago
They seem to be basing the behavior on the Tor Browser which is described here: https://blog.torproject.org/browser-fingerprinting-introduction-and-challenges-ahead/ https://blog.torproject.org/browser-fingerprinting-introduct... The Mullvad Browser download page has this to say: "Strong anti-fingerprinting from the Tor Project The Tor Project has a proven track record of building a privacy-focused browser. The Mullvad Browser has the same fingerprinting protection as the Tor Browser – it just connects to the internet with (or without) a VPN instead of the Tor Network."
kfreds 3y ago
> What does masking specifically mean? Here's a complete list of settings and modifications: https://mullvad.net/en/browser/hard-facts https://mullvad.net/en/browser/hard-facts
pavon 3y ago
It is using the same profile as Tor Browser which will broaden the group a little. There has been effort to upstream many of these fingerprinting resistance changes to Firefox, which would broaden the group even more, but I don't know if they are on par yet.
- autoexec 3y ago
  I don't understand why TOR Browser thought that was a good idea either. It seems extremely risky to try to make every browser appear the same and simply hope that they've managed to cover every single means to fingerprint an individual. It's a game of Whac-A-Mole where your adversary is constantly exploring new fingerprinting techniques so TOR/Mullvad has to invest their time and effort into doing the same just so they can counter them all. If they miss anything or don't catch it before or as soon as anyone else does they lose the ability to hide in the crowd entirely. Some amount of research into fingerprinting techniques will always be needed but it seems to me that a far simpler solution would be to randomize the fingerprint for each connection. It doesn't matter if your browser fingerprint is unique as long as it's always changing. That would also make it harder to detect TOR/Mullvad users since they'll look exactly the same as anyone else with a unique fingerprint. It also gives users the ability to modify some of their fingerprint according to their needs without losing protection. For example, they could freely change their useragent for certain websites/requests while still having a unique fingerprint.
  - godelski 3y ago
    Honest question, what's the upside of not doing this? You're already identified as a Tor user via the IP address. But wouldn't a unique, for example, canvas fingerprint just deanonymize you further? A shared fingerprint just makes you indistinguishable from others Tor users. Which you're already being classified as and can't escape that printing.
    - autoexec 3y ago
      IP addresses won't necessarily ID a TOR user unless all exit nodes are known and being checked for. The TOR browser fingerprint stands out like a sore thumb though. The shared fingerprint makes TOR users indistinguishable from other TOR users unless/until a single identifying factor isn't accounted for at which point all TOR users are identifiable on every connection, across time, different domains, etc. The sameness of TOR user's fingerprints + even just one consistent identifying feature means TOR users could be individually tracked. A unique canvas fingerprint can be used to track you, but as long as it's differently unique on every request it can't be used to track you because the resulting fingerprint will always be different. The "hide in the crowd" trick of trying to make a bunch of different people's browsers look identical isn't a bad thing, it's just extremely fragile. Still, it's better than nothing. Making all browsers randomize their fingerprint every time defeats tracking just as well as the "hide in the crowd" trick does (when that trick is 100% perfect) but also adds resilience and flexibility
eggnet 3y ago
You can already tell Mullvad users from their IP address. If their browser only reveals that much, that sounds like a win to me.
- matthewaveryusa 3y ago
  good point!
Bu9818 3y ago
The alternative (faking Chrome or something) is extremely difficult, especially with a different codebase. There's going to be differences. You can tell if someone is using this browser if they're using Tor/Mullvad too. It's just a better option to create a new identity (TB/Mullvad) and put everyone behind that.
deleted 3y ago
[deleted]

em-bee 3y ago

considering the difference between the words mask and hide, i would assume it's replacing them with canned values.

reaperducer 3y ago
Hopefully the values rotate randomly through a common set of values, rather than just making everyone Windows 11/Chrome.
- smegsicle 3y ago
  the 'scanner darkly' method, i think xxxterm used to do that probably more annoying to fingerprint in general, but its own signal in another way
  - em-bee 3y ago
    well, each individual browser should not rotate the values to often, every few weeks or months maybe, if at all, or when sessions are cleared. or they could differ per site. but across all browser instances a statistical distribution of values that is similar to the existing distribution would help to ensure that no particular value stands out. given that it is firefox this should also mean that only average firefox values should be used because the browser itself can be detected through checking feature differences which can't be masked as easily.

RamRodification 3y ago

"a similar fingerprint for all of its users", to me, makes it sound like they accept the fact that users will be fingerpritable as Mullvad Browser users (but not more precise than that). Actually, which other crowd could they even be referring to with "hide-in-the-crowd"?

mpixel 3y ago
let's say windows 11 users who use google chrome
- ISO-morphism 3y ago
  Not sure if you're being sarcastic or not, but Windows 11 users who use Google chrome are only really a crowd at the User Agent string level. Chrome allows much deeper fingerprinting.
- Bu9818 3y ago
  It's going to be extremely difficult to imitate another browser like that, especially one of a different codebase. Chrome is extremely fingerprintable too.

Sakos 3y ago

They seem to be basing the behavior on the Tor Browser which is described here: https://blog.torproject.org/browser-fingerprinting-introduction-and-challenges-ahead/ https://blog.torproject.org/browser-fingerprinting-introduct... The Mullvad Browser download page has this to say: "Strong anti-fingerprinting from the Tor Project The Tor Project has a proven track record of building a privacy-focused browser. The Mullvad Browser has the same fingerprinting protection as the Tor Browser – it just connects to the internet with (or without) a VPN instead of the Tor Network."

kfreds 3y ago

> What does masking specifically mean? Here's a complete list of settings and modifications: https://mullvad.net/en/browser/hard-facts https://mullvad.net/en/browser/hard-facts

pavon 3y ago

It is using the same profile as Tor Browser which will broaden the group a little. There has been effort to upstream many of these fingerprinting resistance changes to Firefox, which would broaden the group even more, but I don't know if they are on par yet.

autoexec 3y ago
I don't understand why TOR Browser thought that was a good idea either. It seems extremely risky to try to make every browser appear the same and simply hope that they've managed to cover every single means to fingerprint an individual. It's a game of Whac-A-Mole where your adversary is constantly exploring new fingerprinting techniques so TOR/Mullvad has to invest their time and effort into doing the same just so they can counter them all. If they miss anything or don't catch it before or as soon as anyone else does they lose the ability to hide in the crowd entirely. Some amount of research into fingerprinting techniques will always be needed but it seems to me that a far simpler solution would be to randomize the fingerprint for each connection. It doesn't matter if your browser fingerprint is unique as long as it's always changing. That would also make it harder to detect TOR/Mullvad users since they'll look exactly the same as anyone else with a unique fingerprint. It also gives users the ability to modify some of their fingerprint according to their needs without losing protection. For example, they could freely change their useragent for certain websites/requests while still having a unique fingerprint.
- godelski 3y ago
  Honest question, what's the upside of not doing this? You're already identified as a Tor user via the IP address. But wouldn't a unique, for example, canvas fingerprint just deanonymize you further? A shared fingerprint just makes you indistinguishable from others Tor users. Which you're already being classified as and can't escape that printing.
  - autoexec 3y ago
    IP addresses won't necessarily ID a TOR user unless all exit nodes are known and being checked for. The TOR browser fingerprint stands out like a sore thumb though. The shared fingerprint makes TOR users indistinguishable from other TOR users unless/until a single identifying factor isn't accounted for at which point all TOR users are identifiable on every connection, across time, different domains, etc. The sameness of TOR user's fingerprints + even just one consistent identifying feature means TOR users could be individually tracked. A unique canvas fingerprint can be used to track you, but as long as it's differently unique on every request it can't be used to track you because the resulting fingerprint will always be different. The "hide in the crowd" trick of trying to make a bunch of different people's browsers look identical isn't a bad thing, it's just extremely fragile. Still, it's better than nothing. Making all browsers randomize their fingerprint every time defeats tracking just as well as the "hide in the crowd" trick does (when that trick is 100% perfect) but also adds resilience and flexibility

eggnet 3y ago

You can already tell Mullvad users from their IP address. If their browser only reveals that much, that sounds like a win to me.

matthewaveryusa 3y ago
good point!

Bu9818 3y ago

The alternative (faking Chrome or something) is extremely difficult, especially with a different codebase. There's going to be differences. You can tell if someone is using this browser if they're using Tor/Mullvad too. It's just a better option to create a new identity (TB/Mullvad) and put everyone behind that.

deleted 3y ago

[deleted]