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Fingerprinting protection doesn't hide version number in 103

  • 4 respuestas
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  • Última respuesta de cor-el

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I went to amiunique.org (suggested even in the fingerprinting protection article) and found that using Firefox v103 is extremely uncommon as of today, nearly enough to identify my browser. I thought Firefox was supposed to spoof the version number with fingerprinting protection enabled. Does it only hide minor version numbers? That doesn't seem to cut it for fingerprinting.

I went to amiunique.org (suggested even in the fingerprinting protection article) and found that using Firefox v103 is extremely uncommon as of today, nearly enough to identify my browser. I thought Firefox was supposed to spoof the version number with fingerprinting protection enabled. Does it only hide minor version numbers? That doesn't seem to cut it for fingerprinting.

Todas las respuestas (4)

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I can confirm the behavior, but I don't know whether it was an intentional change.

If you want Firefox to report a different version to sites, you can try this preference added in Firefox 100 to help with sites that can't handle 3-digit version numbers:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. This one is documented in Difficulties opening or using a website in Firefox 100.

(2) In the search box in the page, type or paste network.http.useragent.forceVersion and pause while the list is filtered

(3) Double-click the preference to display an editing field, and change the value to 91 or whatever version you like, then press Enter or click the blue check mark button to save the change.

This takes effect the next time you exit out of Firefox and start it up again.

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Regarding what is common, Firefox 103 was released about two weeks ago, I think, and probably is the most common version of Firefox in use today. It's just that Firefox users are a rarer breed these days.

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Yes, this change in Firefox 102+ to show the current release and the Windows 10 platform in the user agent is intentional because most Firefox users use the current release and not the current ESR version. This is different from what is reported in the Navigator object.

Websites that check for a (unique) fingerprint use a database of visitors of their website and it is not likely that all use the same Firefox version and browser configuration, so every Firefox user likely shows as unique.


resistFingerprinting: report Firefox's real major version instead of the ESR version.

  • 1769022 - RFP: userAgent.AppendInt(spoofedVersion) !== 102

GetSpoofedVersion and GetSpoofedUserAgent:

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I had reported this some time ago on the RFP discussion forum, but apparently this wasn't important enough to update the article.