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Supercookie: Browser Fingerprinting via Favicon

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Re: Supercookie: Browser Fingerprinting via Favicon

#31
Some users (including myself) disable favicons, since I don't use favicons. (I disabled it when I set up the computer, far before I heard anything about favicon supercookies.)

In this case, it may be able to figure out that favicons are disabled (if the implementation is written to support that), but not more than that.

Re: Supercookie: Browser Fingerprinting via Favicon

#33

This is a neat approach, but I'm not sure I'd expect it to be used in the wild. ~32 consecutive document redirects every time you want to fingerprint a browser would be slow: twelve (?) redirects on my (~fast) internet takes about ten seconds. On 3g, I could imagine this taking much longer. You'd also likely need to do this at the (root) page level (i.e., it wouldn't work inside an iframe, since iframes don't have fa…

I think you could also run this on an iframe embedded in a page

Re: Supercookie: Browser Fingerprinting via Favicon

#35
post #33

This is a neat approach, but I'm not sure I'd expect it to be used in the wild. ~32 consecutive document redirects every time you want to fingerprint a browser would be slow: twelve (?) redirects on my (~fast) internet takes about ten seconds. On 3g, I could imagine this taking much longer. You'd also likely need to do this at the (root) page level (i.e., it wouldn't work inside an iframe, since iframes don't have fa…

I think you could also run this on an iframe embedded in a page

What is your response to parent's comment that "it wouldn't work inside an iframe, since iframes don't have favicons"?

Re: Supercookie: Browser Fingerprinting via Favicon

#36

Some users (including myself) disable favicons, since I don't use favicons. (I disabled it when I set up the computer, far before I heard anything about favicon supercookies.) In this case, it may be able to figure out that favicons are disabled (if the implementation is written to support that), but not more than that.

I’d say “some users” would be 0.00000001% of users

Re: Supercookie: Browser Fingerprinting via Favicon

#37

This is a neat approach, but I'm not sure I'd expect it to be used in the wild. ~32 consecutive document redirects every time you want to fingerprint a browser would be slow: twelve (?) redirects on my (~fast) internet takes about ten seconds. On 3g, I could imagine this taking much longer. You'd also likely need to do this at the (root) page level (i.e., it wouldn't work inside an iframe, since iframes don't have fa…

Potential workaround: redirect a more bearable amount of times (2-3) every time a user clicks a link on your website. An aggressive ad network could also do this across websites.

Re: Supercookie: Browser Fingerprinting via Favicon

#39
post #33

Earlier quoted context omitted.

I think you could also run this on an iframe embedded in a page

What is your response to parent's comment that "it wouldn't work inside an iframe, since iframes don't have favicons"?

Browsers send requests for favicons for pages in iframes even though they are not showing them.

Re: Supercookie: Browser Fingerprinting via Favicon

#40

Earlier quoted context omitted.

It may have been their intention, after reading the bugzilla report they made[1]. > I also think that it would have been appropriate to notify about the ulterior motive behind this defect report at the latest when the paper got published. This underhanded approach of reporting a defect just leaves a bad taste, really. The behavior may be an actual defect in the classical sense, but I'm just wondering what would have…

Honestly, this is a big deal here. A "security researcher" attempted to _introduce new vulnerabilities_ into a major open source project just so that they could report these vulnerabilities later. How scammy can research get?

Lol, this is downright wild.
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