System Hardening Techniques

System hardening refers to the process of securing a system by reducing its surface of vulnerability. This involves configuring the system more securely and eliminating unnecessary services or applications. In the context of Linux, system hardening is crucial for protecting sensitive data and maintaining system integrity.

• Attack Surface: The total number of vulnerabilities in a system that can be exploited by an attacker.
• Principle of Least Privilege: Users and processes should have only the minimum privileges necessary to perform their tasks.
• Defense in Depth: Implementing multiple layers of security controls to protect resources.

1. Update the System: Always keep your system updated with the latest security patches.
Tip: Use yum update or apt update depending on your distribution.
2. Remove Unnecessary Packages: Uninstall any software that is not needed.
3. Configure User Accounts: Disable root login and enforce strong password policies.
4. Set Up Firewall: Use tools like iptables or firewalld to configure a firewall.
5. Secure SSH: Change the default SSH port and disable password authentication.
Warning: Always use key-based authentication for SSH.
6. Enable SELinux: Use SELinux for an additional layer of security on your Linux system.
7. Regular Backups: Implement a backup strategy to recover from any potential breaches.

• Regularly review security logs and monitor system activity.
• Implement multi-factor authentication wherever possible.
• Conduct regular security audits and vulnerability assessments.
• Educate users about security risks and best practices.