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What is Browser Fingerprinting and How to Protect Yourself

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What is browser fingerprinting?

A standard investigative method in regulation enforcement is to gather fingerprints on the scene of a criminal offense. On the time of assortment, it’s not recognized who these fingerprints belong to, so the objective is wholesale assortment for later evaluation. These fingerprints are later matched towards a database of fingerprints with recognized house owners to determine particular individuals.

Browser fingerprinting, a.okay.a. canvas fingerprinting, works in the identical means: the wholesale assortment of as many browser identification factors as potential at an internet site that may then be later matched towards the browser traits of recognized individuals. In each kinds of fingerprinting, evaluation might not reveal the determine of an individual however can nonetheless present that the identical individual carried out totally different actions.

Most privateness fanatics are conscious that the first method during which they are often recognized on-line is by means of using their IP tackle. TCP/IP, the protocol suite that the web makes use of, essentially requires that your IP handle be despatched with each request to ensure that the online server to know the place to ship the response.

Digital Personal Networks (VPNs) have develop into widespread over the previous few years as a approach to disguise your actual IP tackle by borrowing an IP handle out of your VPN supplier that is shared by many individuals. This successfully hides your actual IP tackle. Visitors within the net server’s log merely exhibits the VPNs IP tackle. However what else does your browser ship that a VPN can’t scrub out? A lot of that is determined by your browser configuration, however a few of it merely can’t be helped. Correlating the info in your browser’s requests can permit somebody to determine you, even in case you’re utilizing a VPN.

How is fingerprinting accomplished?

The info assortment could be executed in two methods; on the server and by way of client-side applied sciences like JavaScript and Adobe Flash®.

Server-Aspect Assortment

Web site entry logs on the server can gather knowledge that is despatched by your browser. At a minimal, that is often the protocol and URL requested, the requesting IP handle, the referer (sic) and the consumer agent string.



Let’s take a look at a normal Nginx entry log entry of a request utilizing the Safari browser. It seems like this:

11.22.33.four – – [18/Apr/2017:08:04:17 -0300] “GET /using-expressvpn-with-ubuntu-linux-mint-or-debian-linux/HTTP/1.1” 200 12539 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30”


My IP tackle, browser and working system are included within the request. The browser and working system are included within the consumer agent string which is this a part of the request:

Mozilla/ (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Model/10.1 Safari/603.1.30″


If I load the same page using Chrome, the only difference is that user agent now shows as Chrome. The log shows the same IP and the same operating system. Two points are not enough to draw a concrete comparison, but it is enough to indicate that these two requests could have come from the same person. – – [18/Apr/2017:08:05:36 -0300] “GET /using-expressvpn-with-ubuntu-linux-mint-or-debian-linux/ HTTP/1.1” 200 12581 “-” “Mozilla/ (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ Safari/537.36”


Net servers may also be configured to log far more knowledge in its entry logs through the use of log format specifiers.

As well as to what could also be recorded in net server entry logs, browsers additionally ship a collection of headers. The online server wants to know what varieties of content material and compression that the browser understands. It is additionally extraordinarily widespread for cookies to be exchanged between browsers and net servers. Within the developer instruments of my Chrome browser, I see that these headers have been additionally despatched with my request and could be additional used to fingerprint by browser:
settle for:textual content/html,software/xhtml+xml,software/xml;q=zero.9,picture/webp,*/*;q=zero.eight
accept-encoding:gzip, deflate, sdch, br
cookie:_ga=GA1.2.251051396.1499461219; _gat=1
user-agent:Mozilla/ (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ Safari/537.36

Shopper-Aspect Assortment

That is the server-side info that is simply collected, however our previous client-side pals JavaScript and Adobe Flash® will betray a lot, far more about your browser. There are a selection of web sites on the web that may present how a lot knowledge your browser will present when requested.

For instance, I study from Am I Distinctive? that my browser will present a frightening record of data from my browser resembling:

  • each font out there on my system
  • the record of plugins I’ve put in
  • the decision of my display
  • the language of my system
  • whether or not my browser accepts cookies
  • and extra. All the listing of what Am I Distinctive collects is right here, and extra is potential.

The desk under is taken from an Am I Distinctive paper1 revealed in March of 2016. Observe that the 2 richest areas of knowledge assortment are the client-side JavaScript and Adobe Flash®



Contemplate the instance above the place the server logs confirmed my IP, browser and working system. Now add within the listing of data that JavaScript and Adobe Flash® provide, and you can begin to see how straightforward it will be to correlate visits. If two visits share precisely the identical set of knowledge apart from the IP tackle, for instance, it might nonetheless be attainable to infer that these visits have been from the identical individual. This is an particularly helpful method when somebody is utilizing a VPN which makes their IP handle much less helpful as an identification level.

When utilizing a VPN, the one knowledge level that modifications is the requester’s IP tackle. Am I Distinctive exhibits that it might acquire 21 factors knowledge factors, not even together with the three knowledge factors from the server logs. Subsequently, utilizing a VPN to change one level of knowledge (your IP handle) nonetheless leaves 23 factors of knowledge for comparability.

There is no international normal for human fingerprinting in regulation enforcement, however definitely any fingerprint with 23 matching factors can be thought-about hefty proof.

Replace: Firefox has introduced that it’ll block web sites’ canvas fingerprinting makes an attempt beginning with model 58. You’ll discover within the graphic above that the canvas info from my browser places me in a reasonably small pool of browsers. By issuing particular canvas requests to a browser and hashing the outcomes, web sites can slender that down to a really distinctive fingerprint. Beginning with Firefox 58, the browser will immediate customers to approve canvas requests prior to permitting them.

How does the comparability work?

Most privacy-minded individuals are of the mindset that the much less info you present, the higher your privateness might be. This is true solely in a world the place you possibly can choose to not do issues. For instance, if I don’t need to have any private info on Fb, then I select not to use Fb. Nevertheless, it’s nearly unattainable to not use the web in any respect nowadays, so that you’re essentially going to depart fingerprints behind. Subsequently, the aim right here is to make it troublesome in your personal actions to be correlated to your public actions. Sustaining this separation prevents anybody figuring out you, personally, with knowledge from actions you’d like to hold personal.

Nevertheless, good privateness methods resembling locking down your browser to disallow javascript, cookies, and webRTC requests will solely make your browser extra distinctive since fewer individuals do this. For instance, utilizing the Digital Frontier Basis’s Panopticlick we will see the distinction within the two configurations. With Javascript enabled, my browser is simply trackable:



With javascript turned off, my browser is nonetheless trackable, nevertheless it turns into so distinctive that it solely matches 1 in about 100,000 browsers. When you think about that there are billions of web customers, being 1 in 100,000 is comparatively distinctive.



It’s necessary to word that there is actually little or no fingerprinting knowledge obtainable to check with. Whereas there are a selection of web sites comparable to Am I Distinctive (352,000 data right now), Panopticlick (470,161 data), and others, they’ve a comparatively small quantity of knowledge to work with. As nicely, it’s possible that the majority of that knowledge got here from privacy-minded customers relatively than the overall web inhabitants, so the stats are in all probability not very reflective of the typical web consumer. The actual hazard comes from the likelihood that websites like Fb, with 1.86 billion month-to-month common customers, is compiling large databases of browser fingerprinting knowledge. When very fashionable websites like that begin accumulating browser fingerprint knowledge, the spectre of invisible web monitoring turns into very actual.

The extra distinctive your browser, the better it is to determine throughout websites. So, on this case, it doesn’t actually pay to lock down your browser. However, browsing the online with an insecure browser is a particularly dangerous exercise today, so what’s one of the best answer?

How are you able to shield your self

Since there is no possible approach to safely use the identical browser to do each your personal and public web actions, the perfect safety towards fingerprinting proper now is to separate these two actions. Use one system or browser on your day to day actions and a separate one in your personal actions. It’s greatest to go one step additional and use an anonymity software corresponding to Whonix in your personal actions to guarantee a good bigger separation between your personal and public actions.Sustaining this separation would require good operational safety.

OpSec (Operational Safety)

OpSec is the method of accumulating giant quantities of obtainable details about somebody that appears unrelated at first look, however might be analyzed to present some very particular info. A really apparent instance is logging in to your Fb account whereas utilizing a privateness device similar to Tor. When you’ve logged in, you’ve confirmed your determine with none want for an adversary to analyze your browser fingerprint.

There is no finish to OpSec blunders which may make the correlation of your public and personal web actions simpler, however listed here are some beginning factors.

  1. Your personal web actions ought to by no means contain utilizing any website that you simply additionally use in your public web life. Account correlation, such because the Fb instance, will reduce proper via your privateness makes an attempt.
  2. Your personal actions ought to keep away from composing messages. This protects towards stylometric evaluation. If it is not potential to keep away from composing messages you must search to change your writing fashion considerably.
  3. Use a totally totally different pc system that is completely related to an anonymity device like Tor or a trusted VPN on your personal actions. This helps forestall towards inadvertent knowledge leakage similar to DNS queries or WebRTC requests.
  4. Should you use a VPN for each your personal and public web actions, join to a unique VPN server for every sort of exercise. You might also need to use a VPN with Tor, during which case there are some VPNs that work higher with Tor than others.
  5. Don’t reuse usernames, e-mail addresses, or some other account info out of your public actions inside your personal actions. This protects towards leaving an inadvertent path of breadcrumbs such because the one which helped determine the proprietor of the unlawful Silk Street market.

Separating your actions like this won’t forestall both your public or personal actions from being fingerprinted to a point, however it might forestall the correlation between these two varieties of actions. An observer will in all probability give you the option to inform that the identical individual did these personal actions, however be much less in a position to tie that individual to your public id.

Browser fingerprinting and the GDPR

The GDPR and forthcoming ePrivacy Regulation will possible regulate browser fingerprinting, in addition to different technique of monitoring customers like cookies. The GDPR by no means mentions browser fingerprinting explicitly, however this is intentional; legislators have discovered from previous expertise to hold guidelines impartial of any particular know-how. The ePrivacy Regulation, however, does explicitly point out system fingerprints.

As an alternative, the GDPR merely defines private knowledge as any info that may be linked to an identifiable particular person. This consists of many identifiers together with cookies, IP addresses, promoting IDs, and, sure, fingerprinting. The Digital Frontier Basis explains that “identification does not require establishing a user’s identity:

“It is enough that an entity processing data can indirectly identify a user, based on pseudonymous data, in order to perform certain actions based on such identification (for instance, to present different ads to different users, based on their profiles). This is what EU authorities refer to as singling-out, linkability, or inference.”

The GDPR states any entity that processes private knowledge should show they’ve a reliable cause to do. Moreover, the ePrivacy Directive that may doubtless come into impact in 2019 would require web sites and apps achieve customers’ opt-in consent earlier than monitoring them. On prime of that, companies that fingerprint should permit customers to see what info they gather in addition to its scope, objective, and authorized foundation.

“Browser measurements of AmIUnique fingerprints with an example”. Pierre Laperdrix, Walter Rudametkin, Benoit Baudry. Magnificence and the Beast: Diverting trendy net browsers to construct distinctive browser fingerprints. 37th IEEE Symposium on Safety and Privateness (S&P 2016), Might 2016, San Jose, United States.