CODEWITHSUNDEEP
javascriptsecurityfirefox
ar2015
ar2015

Reputation: 6150

Why and how does firefox reveal its user is in a private mode?

I use firefox and browse a link from this website. It easily detects whether I use private mode and then it blocks me if I am in the private mode.

I searched on stackoverflow.

This answer says it is impossible. But, this website has made it possible.

Another answer suggests

var db = indexedDB.open("test");
db.onerror = function(){alert('Firefox PB enabled')};
db.onsuccess =function(){alert('Not enabled')};

And this method works fine. Although, I am not sure if the mentioned website uses the same technique.

Then, I am wondering about two questions:

1- Is this the only way to detect the private mode in firefox?

2- Why does firefox stab back its users? Is it a part of its design or is it a bug in firefox?

Upvotes: 1

Views: 140

Answers (1)

KIKO Software
KIKO Software

Reputation: 16751

See this bug report. Reading that should answer you second questions. They know the problem, have tried to work on it, but clearly without success up to now. Some developers think it's stupid to make indexedDB (partially) work:

Don't expose the API if every operation is going to fail.

As for your first question. There are other methods, and most browsers seem to be susceptible. Here's an article from February '19: Google wants to make it harder for sites to detect that you’re using Chrome’s Incognito Mode.

I want to add that every website has the right to refuse visitors for whatever reason they see fit. Visiting a website is not a right, it's a privilege. Your link to the joplinglobe.com for instance, doesn't work for me because I am in Europe. This happens on a lot of sites in the USA. The reason is that they want to track users in a way that is not compatible with European law (basically: Tell people what you do, and provide or remove personal data when requested), it is easier for the sites to block access to visitors they don't care about than to spent a day thinking about the privacy of their visitors.

Upvotes: 2

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