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How can this website circumvent Firefox's privacy settings?

  • 6 replies
  • 4 have this problem
  • 466 views
  • Last reply by cor-el

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A newspaper called Folha seems able to store something in my local drive and also to access it later in order to identify me even though I have blocked all of its cookies (and also checked the page source code and identified possible third party cookies, blocking them as well).

But it gets creepy: when I open a new private window, it still identifies me.

And creepier: when I use a second (fresh) profile, it still identifies me.

And worse: it afects all other browsers installed in my computer as well!

(See Chrome, Opera and Internet Explorer, all of them in private browsing mode:) https://flic.kr/p/qvdAij https://flic.kr/p/qMLTQt https://flic.kr/p/qMBE2v

An example of URL in which this happens (after other articles have been visited until finally reaching the site's paywall) is http://www1.folha.uol.com.br/colunas/redesocial/2015/01/1574239-liberdade-igualdade-e-fraternidade-na-franca-para-quem.shtml

It could be a server-side mechanism, but I have a dynamic IP, not a static one.

Since Firefox is my primary browser, something "got in" to my computer through it and from this website. What could it be? And how could one prevent it on this and other websites?

(There's a suspicious script linked in the page's source, hosted at http://tag.navdmp.com/tm23947.js, but I can't tell what it does.)

Chosen solution

when i accessed the http://www1.folha.uol.com.br/colunas/redesocial/2015/01/1574239-liberdade-igualdade-e-fraternidade-na-franca-para-quem.shtml link on my machine the first time, i get the paywall right from the start - so probably that's a policy change by the website an not a particularly sophisticated tracking mechanism...

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All Replies (6)

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hello, which feedback do you get that indicates the site is identifying/tracking you?

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Philipp, normally one would be able to read the article, but once you've reached a certain number of visits it blocks you from reading, dimming the article and showing this image in the center: http://f.i.uol.com.br/paywall/trj-acesso-restrito-limite-731x425-20141222.png ("Access restricted to subscribers and registered users, etc.")

That's what the three screenshots above show (sorry, I didn't make it clear, but the screenshots all refer to that exact link), and, by the way, here's a screenshot of a private browsing window of my Firefox's second profile doing the same: https://flic.kr/p/qve4qW

Please let me know if I can provide any other information.

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Chosen Solution

when i accessed the http://www1.folha.uol.com.br/colunas/redesocial/2015/01/1574239-liberdade-igualdade-e-fraternidade-na-franca-para-quem.shtml link on my machine the first time, i get the paywall right from the start - so probably that's a policy change by the website an not a particularly sophisticated tracking mechanism...

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I can see its using "window.localStorage.setItem(id,data); " Here is some explanation from http://cssmenumaker.com/blog/localstorage-basics

"Let's clear up some of the ideas around localStorage. You might be aware of "cookies", which sites use to remember you or your login. Cookies are very limited in size, and really aren't meant to store actual data. localStorage, on the other hand, is meant for sites to have a 5-10MB space on your PC to save whatever they may need. This storage is NOT sent to the server, in contrast to cookies. This means all data stored with localStorage is kept on that one computer, and only accessible by the browser you used to create the data. Every modern browser supports this, so let's look into the code (Javascript knowledge is needed): You can access localStorage with window.localStorage. If you type that into a console, you'll probably see that the current site you call it from isn't using it.

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It really seems to be an article-related (or section-related) issue, because http://www1.folha.uol.com.br/mercado/2015/01/1574176-acionistas-minoritarios-brasileiros-decidem-ir-a-justica-contra-petrobras.shtml opens correctly, for example. So false alarm, I guess. (Better this way, though...) Thank you both!

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Note that current Firefox releases have a Storage Inspector that allows to inspect cookies and datstored in local (DOM) storage.