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"
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("")
);
}
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.
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.
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.
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.
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.
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.
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.
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.
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"