It’s not admin, it’s NTAuth\SYSTEM, a much much higher privileged account.
System is the most powerful account in Windows, bypassing almost any system protection in place such as group policy, privilege and permissions, it can talk out of the box to a DC using the machine account password (this is different to a user password), and essentially become uncontested in a network.
It’s not admin, it’s NTAuth\SYSTEM, a much much higher privileged account. System is the most powerful account in Windows, bypassing almost any system protection in place such as group policy, privilege and permissions, it can talk out of the box to a DC using the machine account password (this is different to a user password), and essentially become uncontested in a network.