While Google has released a security fix for the recently discovered Android "Master Key" vulnerabilities, and the first devices have already been patched, there are millions of rooted Android devices out there which aren't patched and might never receive a patch from the respective OEM or carrier. However, Duo Security, a cloud-based two-factor authentication and mobile security company, and Northeastern University's System Security Lab (NEU SecLab) have joined forces and have developed RegKey. ReKey is a mobile application that fixes the above mentioned "Master Key" vulnerabilities which allow attackers to take full control of a user's mobile device.
With the ReKey mobile app, Android users are able to immediately protect their Android device without waiting on security updates from their mobile carrier. In order to patch the vulnerabilities, ReKey currently requires that the Android device is rooted and running at least Android 2.0.
RegKey is can be downloaded free of charge from the Google Play store and if you are running a rooted Android 2.0+ device and side loading, for instance Beta apps, it's highly recommended to patch your device as soon as possible.
Cheers ~ Arne