AOSX-15-001100 - The macOS system must require individuals to be authenticated with an individual authenticator prior to using a group authenticator.
Administrator users must never log in directly as root. To assure individual accountability and prevent unauthorized access, logging in as root over a remote connection must be disabled. Administrators should only run commands as root after first authenticating with their individual user names and passwords.
To ensure that 'PermitRootLogin' is disabled by sshd, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/^[#]*PermitRootLogin.*/PermitRootLogin no/' /etc/ssh/sshd_config