Enable or Disable Mixed Content Blocking in Firefox

More and more websites are offering their services over the encrypted HTTPS protocol. Accessing websites over HTTPS increases your online security as all the data transfer takes place over an encrypted connection. But cyber-criminals sometimes place HTTP content inside in order to attack the unsuspecting user through the phishing sites. If a webpage is showing HTTPS and HTTP content together, then it is said to have mixed content. If you are a Firefox user, then you can block these mixed content objects to boost your security when accessing secure websites.

There are two types of mixed contents – active mixed content and passive mixed content. The active mixed content is made up of scripts while the passive mixed content is made up of images, videos and other display media items. By default, Firefox blocks only active mixed content and allows the display mixed content. Usually this setting is good enough for most of the users. But if you want to beef up your security even more, then you can block the passive mixed content as well. Here is how:

  1. Open Mozilla Firefox browser. In the location bar type about:config and press Enter.
  2. Firefox will show a warning. Click on the button labeled I’ll be careful I promise! to proceed.

    Enable or Disable Mixed Content Blocking in Firefox

  3. In the Filter field type mixed. You would see a preference named security.mixed_content.block_display_content as shown.

    Enable or Disable Mixed Content Blocking in Firefox

  4. Double click on security.mixed_content.block_display_content to change its value to true.
  5. After changing the value, restart the browser for the changes to take effect.

The mixed content blocking feature a new feature introduced in Firefox version 23. It is very useful in blocking insecure content on secure access websites like the online banking, financial or online shopping sites and other sites which are very often used in the phishing attacks. By enabling the blocking of the display mixed content, you can increase your online security and access the secure sites more confidently.