Firefox Nightly – a test version of the web browser – has been updated to mark websites that send passwords over non-HTTPS connections as “not secure”.
When a user accesses a site with a password field that uses an HTTP connection, a crossed-out padlock will appear on the address bar along with an alert.
“The login information you enter on this page is not secure and could be compromised,” the warning to users says, along with a link for more information.
As Twitter user Richard Barnes explained, the new feature detects whether a page contains an input field with the “password” type and uses an HTTP connection.
If both criteria are met, a page is marked as insecure by the browser.
The feature is being tested in Firefox 44 Nightly, but could be introduced to mainstream Firefox users in a full release at some point in the future.