Which of the following BEST ensures the integrity of a server’s operating system?

A.
Protecting the server in a secure location

B.
Setting a boot password

C.
Hardening the server configuration

D.
Implementing activity logging

Explanation:
Hardening a system means to configure it in the most secure manner (install latest security patches,
properly define the access authorization for users and administrators, disable insecure options and
uninstall unused services) to prevent nonprivileged users from gaining the right to execute
privileged instructions and thus take control of the entire machine, jeopardizing the OS’s integrity.
Protecting the server in a secure location and setting a boot password are good practices, but do
not ensure that a user will not try to exploit logical vulnerabilities and compromise the OS. Activity
logging has two weaknesses in this scenario-it is a detective control (not a preventive one), and
the attacker who already gained privileged accesscan modify logs or disable them.