Disable password-based authentication ( PasswordAuthentication no ) in favor of SSH key-pair authentication .
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 in /etc/ssh/sshd_config . Linux Server Hardening
Below is a structured write-up covering the essential stages of a Linux hardening project. 1. Update and Patch Management
Run system updates immediately upon setup (e.g., apt update && apt upgrade for Debian/Ubuntu or dnf update for RHEL/Fedora). Secure Access (SSH Hardening) Prevent direct root access
Moving SSH from port 22 to a non-standard port can eliminate up to 99% of automated scans. 3. Identity and Access Management
Securing the primary remote entry point is vital for stopping automated brute-force attacks. Update and Patch Management Run system updates immediately
The most critical step is ensuring all software is current to close known vulnerabilities.