It is always tempting to say ‘yes’ when a browser asks if you want your password saving, even though this means it can be stolen by a Trojan if your computer becomes infected.

However, malware is now affecting Mozilla Firefox which forces the browser to save passwords even when the user chooses not to do so.

The Trojan, which was discovered by Webroot, modifies a file called nsLoginManagerPrompter.js in Firefox.

After a user logs in to a website the file controls whether the browser prompts them to save the password.

However, after being infected with the Trojan, Firefox automatically saves the password without prompting the user.

It then creates a new user account under the name ‘Maestro’ and steals passwords and other information from the registry.

The web domain to which this information is passed has now been closed down, but the Trojan should still be removed from an infected machine by downloading the latest Firefox installer and installing it over the existing installation.

Mozilla has also announced the launch of the beta version of Firefox 4 for Android.

The browser is said to offer the same functions as the desktop browser but with improved speed of performance and response