Secure web pages served over HTTPS may include insecure elements that can leave your information vulnerable to attacks. When a page contains both secure and insecure elements, it's called Mixed Content.
To protect you from the risks related to Mixed Content, Mozilla Firefox blocks insecure content from appearing on otherwise secure pages. If you feel comfortable navigating a page containing insecure elements, you can choose to view this content in a few steps. This article describes how to manage browser controls for accessing Mixed Content for Mozilla Firefox browsers v23 and later.
Managing blocked content settings
You can follow along with this example by opening Firefox and going to https://people.mozilla.org/~tvyas/mixedcontent.html. These pages show the impact of Mixed Content on the browsing experience and how browser settings affect the way a page renders.
When you visit a page with Mixed Content in Firefox, a shield will appear in the location bar. This indicates that some content has been blocked. Select the icon to temporarily disable this security feature and view the insecure content.
Select Disable protection for now if you want to view this content. The page will reload and two icons will appear in the location bar, a shield with a red line through it and a yellow triangle with an exclamation point. These icons are there to remind you that some content on the page may be putting your information at risk.
Mixed Active Content vs. Mixed Passive Content
Mozilla Firefox uses this feature protect your information, but it also allows you to choose whether or not you want to view Mixed Active Content. This type of content can alter how an entire page behaves and potentially steal a user's sensitive data. Mixed Passive Content, however, does not have the ability to alter the entire page's behavior, but only the piece of HTTP (insecure) content itself.
Mixed Passive Content is common online and includes web page elements such as images, audio, and video. Firefox does not automatically block this type of content because it would break a lot of web pages and diminish user experience. However, there is a way to block mixed passive content by editing your browser's configuration.
More information on Mixed Content can be found in the following articles at Mozilla's website:
- How does content that isn't secure affect my safety? Mozilla Support.
- Mixed Content Blocking Enabled in Firefox 23! Tanvi's Blog, Security Engineering at Mozilla.