Keeping your Cloud Desktop Secure
Your Free Cloud Desktop is built on Linux Ubuntu. The Security Updates are checked for automatically and when you do certain actions such as log off, manually check security updates, etc., you will sometimes be prompted to restart from inside the instance to finish updating. It is a good idea to restart the instance from the AWS console from time to time to restart completely.
Ubuntu does a great job keeping things up to date. By doing the above to help keep your instance up to date, things like shellshock and heartbleed can be fixed as a part of normal maintenance.