The most critical step is ensuring all software is current to close known vulnerabilities.
Linux server hardening is the process of reducing a system's attack surface to protect against unauthorized access and data breaches. A default Linux installation is often a "blank canvas" rather than a fortress; hardening provides the necessary reinforcement.
Configure automatic security updates using tools like unattended-upgrades on Debian/Ubuntu or dnf-automatic on RHEL/Fedora. 2. Secure Access (SSH Hardening)