If you have Apple devices running High Sierra, there is a critical vulnerability that will allow anyone to access the device if they can get their hands on it. All that needs to be done is log in as guest. Then via System Preferences>Users & Groups>Click the lock to make changes. Then use “root” with no password. Try it for several times. When the problem is exploited, the user is authenticated into a “System Administrator” account and is given full ability to view files and even reset or change passwords for pre-existing users on that machine.
The following can be done to prevent the problem from occurring prior to Apple releases the fix.