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by aerotwelve
2932 days ago
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What's the best way to circumvent this? Is it even possible? I'm no expert (which is why I ask), but I assume that blocking third-party cookies in your browser won't prevent situations like the tracker example the author provides. That is, since you visited tracker at least once, their cookie would have been set during that visit as a first-party cookie, and therefore the http requests to retrieve the 1x1 transparent image from their server will contain the data they're after, right? |
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1) Get rid of the misfeatures that allow the problem to exist. Change the browser to never send headers that leak information by design (Referer, Cookie, Etag, User-Agent, etc).
1.1) (Optional) Fix stateful sessions that previously depended on cookies with a new HTTP session+authentication feature (that doesn't have the problems that made the Authorization header mostly useless).
2) Strip most of the other HTTP headers that leak bits of entropy so the browser fingerprint is too small (~16 bits max?) to be a unique id.
2.1) (Optional) Add some of the removed functionality back as a single header that reports a single "browser class" out of a handful (<32, 4-5 bits max. ~8 would be better) of predefined classes (e.g. "Standard Desktop with screen size between H1xW1 and H2xW2 with >=2 channel audio output. Supported codecs: audio=[MP3, AAC], video codec [...]", "mobile with multitouch screen with size ...etc...").
3) Disable Javascript. Running Turing complete code from potentially malicious remote hosts will always be dangerous, because it isn't possible to answer any question about the behavior of a program without running it (halting problem in general; Turing machines with >=7918 states cannot[1] be proven with ZF set theory). A safe web of documents is possible. Software needs to be handled separately.
Of course, none of this will happen because the people with the power to make most of these changes derive a lot of their income from surveillance.
[1] https://www.scottaaronson.com/blog/?p=2725