System hardening is mainly focused on?

System hardening is primarily focused on reducing the attack surface of a system by strengthening its configuration and eliminating vulnerabilities. This involves disabling unnecessary ports and services because each open port or running service could potentially serve as an avenue for an attacker to exploit the system. By minimizing these entry points, the overall security posture of the system is significantly improved, making it less likely to be compromised.

In the context of the other choices, while creating backup data is essential for recovery, it does not directly contribute to making the system more secure at a fundamental level. Updating software is crucial for addressing vulnerabilities but is different from hardening, which specifically targets the configuration and operational state of the system. Increasing system performance is important in its own right but does not necessarily relate to the security enhancements that come from hardening. Thus, the focus on disabling unnecessary ports and services aligns directly with the goals of system hardening.