Mozilla Security Blog

Firefox 86 Introduces Total Cookie Protection

Today we are pleased to announce Total Cookie Protection, a major privacy advance in Firefox built into ETP Strict Mode. Total Cookie Protection confines cookies to the site where they … Read more

Firefox 85 Cracks Down on Supercookies

Trackers and adtech companies have long abused browser features to follow people around the web. Since 2018, we have been dedicated to reducing the number of ways our users can … Read more

Encrypted Client Hello: the future of ESNI in Firefox

Background Two years ago, we announced experimental support for the privacy-protecting Encrypted Server Name Indication (ESNI) extension in Firefox Nightly. The Server Name Indication (SNI) TLS extension enables server and … Read more

Design of the CRLite Infrastructure

Firefox is the only major browser that still evaluates every website it connects to whether the certificate used has been reported as revoked. Firefox users are notified of all connections … Read more

Measuring Middlebox Interference with DNS Records

Overview The Domain Name System (DNS) is often referred to as the “phonebook of the Internet.” It is responsible for translating human readable domain names–such as mozilla.org–into IP addresses, which … Read more

Firefox 83 introduces HTTPS-Only Mode

  Security on the web matters. Whenever you connect to a web page and enter a password, a credit card number, or other sensitive information, you want to be sure … Read more