Security in depth with Ubuntu

In-depth security with Ubuntu involves a layered defense strategy that protects the system at every level—from the kernel to the user. It starts with enforcing strict user access controls and the principle of least privilege using sudo, followed by hardening the system with tools like UFW (Uncomplicated Firewall), AppArmor for application confinement, and Fail2Ban to block brute-force attacks. Regular system updates via unattended-upgrades ensure vulnerabilities are patched quickly, while intrusion detection tools like AIDE and Auditd help monitor file integrity and log suspicious activity. Network security is enhanced by disabling unused ports and services, using SSH key authentication, and optionally setting up VPNs. Full-disk encryption with LUKS, secure backups, and physical protections like BIOS locks complete a robust Ubuntu security posture, making it resilient against both internal and external threats.