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.
Prevent direct root access by setting PermitRootLogin no in /etc/ssh/sshd_config . Linux Server Hardening
Disable password-based authentication ( PasswordAuthentication no ) in favor of SSH key-pair authentication .
Securing the primary remote entry point is vital for stopping automated brute-force attacks. The most critical step is ensuring all software
Follow the principle of least privilege to limit what users and services can do.
Configure automatic security updates using tools like unattended-upgrades on Debian/Ubuntu or dnf-automatic on RHEL/Fedora. 2. Secure Access (SSH Hardening) Prevent direct root access by setting PermitRootLogin no
Moving SSH from port 22 to a non-standard port can eliminate up to 99% of automated scans. 3. Identity and Access Management