Security researcher Jimmy Bayne with a Publication on Twitter announced a vacancy on settings issues of Windows 10 which may allow to maliciousangry users have your credentials stolen.
How; creating a theme they can carry out a "Pass-the-Hash" attack.
The ability to install themes from other sources allows them to create malicious themes that, when opened, redirect users to a page asking them to enter their credentials.
Windows allows users to change themes from Settings - Personalization by right-clicking on the currently active theme. Then select "Save theme for sharing". This will create a ".deskthemepack" file that you can share via email or as you wish. The new file can be installed.
Intruders can also create a ".theme" file where the default wallpaper setting leads to a malicious site that requires authentication. There unsuspecting users give their credentials, which are sent with NTLM encryption to the site. The passwords are then read using a special decryption software.
The researcher mentioned a way of protection for these attacks. Extensions such as ".theme", ".themepack" and ".desktopthemepackfile" should be disabled.
Bayne reports that these findings were disclosed to the Microsoft Security Response Center (MSRC). However, the error not fixed because it was "by design". It is not known if the company plans to fix the bug after this disclosure or if it changes the file structure for the themes to prevent redirects to sites that require authentication.
If you consider that most users are logged into their accounts with the account of Microsoft in Windows 10, credential theft puts a lot of user data at risk – such as email, OneDrive or even Azure data.