I've used Mimikatz to patch the domain controller with a skeleton key
misc::skeleton, which makes it possible for any domain user to authenticate with the password "mimikatz", while still being able to use their original password.
However, what is it that allows this to happen on the domain controller? In other words, how can a username be associated to multiple passwords?
Off-topic: Is it possible to change the master password ("mimikatz") to something else on the mimikatz command-line?