Brave

Current status

Detail Description
Mechanism Shields
Originally deployed in 0.55.18
Latest update deployed in v1.30.86
Latest update includes No longer block requests to filtered origins if the requests are same-site with the site the user is browsing.
User controls Site-specific and global controls for:
  • Cross-site tracker blocking
  • Automatic connection upgrade to HTTPS
  • Script blocking
  • Cookie blocking
  • Device recognition blocking

Brave Shields default settings

Classification of “known trackers”

Brave classifies tracking domains using input from multiple lists:

Brave matches each outgoing request from the web browser against these lists (using various methods for achieving optimized performance), and if a match is made, the request is blocked.

Note! If the resource that should be blocked is same-site to the site the user is browsing, the request will not be blocked. Thus if the user is browsing www.domain.com and the browser sends a request to blocked-tracker.domain.com (which is in Brave’s filter lists), the request will not be blocked.

Example: The user visits a site that tries to load the Google Analytics JavaScript library from https://www.google-analytics.com/analytics.js. This URL (and the entire domain, in fact), is listed in the EasyPrivacy list. Thus Brave blocks the request, preventing the browser from downloading the library and executing the Google Analytics tracking code in the web browser.

By blocking requests upstream, it means that if the request initiated a resource download (such as a JavaScript library), this resource is never downloaded and thus the code is not executed in the user’s browser. If the request initiated a pixel call (such as a GET for an image), it means the pixel call will be aborted before it is received by the endpoint.

Third-party cookies

All third-party cookies are blocked by default in subresource requests (e.g. CDN loads, pixel pings).

Brave uses "cross-site" interchangeably with "third-party" in this case

In frames (e.g. <iframe>), access is partitioned and set to site-length expiration.

Partitioned access means that the document.cookie API will work in a cross-site <iframe>, but the storage will be unique between the site embedding the frame and the frame itself. Another site embedding the same frame would have a different storage profile.

Site-length expiration means that as soon as the last page of the site embedding the cross-site frame is closed, the partitioned storage is cleared. This is different to how e.g. Safari works, where the storage is cleared only upon the browser being closed (this clears the storage also in Brave).

First-party cookies

For cookies set with JavaScript’s document.cookie, expiration is set to a maximum of 7 days.

Example: The user visits a page that is running an A/B testing tool which stores the experiment details into a cookie named __exp. This cookie is set with JavaScript. Even though setting the cookie works, and the user is assigned to an experiment group successfully, if the user takes more than 7 days to revisit the site, the cookie will have been expired and the user would potentially get assigned to a new, different group upon their next visit.

For cookies set with the Set-Cookie HTTP response header, expiration is set to a maximum of 6 months.

Other third-party storage

Partitioned and site-length expiration for localStorage and sessionStorage APIs (see Third-party cookies for more information).

Note that since Brave blocks resources found in their classification lists, it has the downstream effect of blocking storage access from these vendors who now can’t execute their JavaScript in the user’s browser or respond to the blocked HTTP requests.

Other first-party storage

No restrictions.

Note that since Brave blocks resources found in their classification lists, it has the downstream effect of blocking storage access from these vendors who now can’t execute their JavaScript in the user’s browser, or respond to the blocked HTTP requests.

CNAME cloaking

Brave Shields blocks network requests to domains in Brave’s blocklists. With version 1.17.73, Brave now also resolves the DNS of any given domain and identifies if there are CNAME records pointing to domains that are in the blocklists, and blocks these as a result, too.

Example: The web page sends a pixel request to https://measure.example. This domain is not in Brave’s blocklist, so Brave would normally allow the network request to complete. However, measure.example is a CNAME record which actually points to track.everything, which is in Brave’s blocklist. As the domain the CNAME points to is in Brave’s blocklist, Brave blocks the initial request to https://measure.example as a consequence.

Referrer

Cross-site referrers are spoofed in non-navigational HTTP requests.

Example: If the page on https://domain.com/page requests a resource from https://anotherdomain.com/image.jpg, the referer header in the HTTP requests will be set to the referred-to origin (https://anotherdomain.com/) rather than the referred-from origin (https://domain.com/) as is the typical behavior.

For top-level navigation, cross-site referrers default to strict-origin-when-cross-origin unless the site requires an even stricter policy..

Example: When clicking a link from https://domain.com/page to https://anotherdomain.com/another-page/, the referer header is set to https://domain.com. Similarly, the document.referrer will be set to https://domain.com once the user lands on anotherdomain.com.

For same-site requests (both navigational and non-navigational), referrer has normal behavior.

Other

Brave removes known tracker identifier parameters from URL strings. On top-level navigation (e.g. landing on a page with such parameters in the URL), the parameters are stripped out in a 307 internal redirect. On non-navigational HTTP requests, the parameter is stripped from the request URL.

Here is the list of parameters that are stripped:

  • fbclid (Facebook)
  • gclid (Google)
  • msclkid (Microsoft)
  • mc_eid (Mailchimp)
  • yclid (Yandex/Yahoo)
  • _hsenc, __hssc, __hstc, __hsfp, hsCtaTracking (HubSpot)

Example: If the user types https://www.domain.com/?fbclid=1.2.3.4 in the omnibox and presses enter, Brave strips the parameter in an internal redirect. Similarly, if the browser makes a request to https://www.domain.com/tracking-pixel.gif?mc_eid=23456, Brave strips the parameter out of the request before it hits the target server.

Brave has lots of initiatives for neutralizing fingerprinting surfaces, with features such as randomized HTML canvas fingerprints preferred over just removing or clearing the fingerprint surfaces.

On macOS Brave, the version number in the User Agent string is frozen to 10_15_7 to fix compatibility issues with upgrading to macOS version 11+ (Big Sur). This has obvious privacy implications as well, as the platform version is no longer useful for fingerprinting purposes.

Sample User Agent string when running Brave 1.24.85 on macOS 11.3.1:
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36"

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