Server security hardening is a crucial process that involves implementing various strategies to minimize vulnerabilities and secure your server from potential threats. This guide provides some good practices for enhancing the security of your server.
The guide does not cover all practices but covers some crucial ones that, will mostly secure your server.
You can always exploit more tools and security practices
1. Use Strong Passwords and Authentication #
Below are some of the practices that you could adopt for this
a . Enforce Strong Passwords #
- Ensure that the root user account and all other accounts on your server use strong passwords with a mix of letters, numbers, and special characters.
- You cloud use tools like Password Generators to generate strong passwords that meed the secure standards
b. Disable SSH Password authentication #
This involves disabling SSH password authentication for all users
- Use SSH keys instead of passwords for remote login to prevent brute-force attacks.
- This will need you to first set up SSH keys for your users. Here is how to
- You will then disable password authentication by editing the SSH configuration file
/etc/ssh/sshd_config- You will then add this line to the file
PasswordAuthentication no2. Secure SSH Configuration #
a. Disable SSH Root Login
- This involves completely disabling root SSH while you enable SSH for other users
- You can do that by following these steps
b. Disable root SSH with password but allow with Keys
- Instead of completely disabling root SSH, this option involves taking a cautious step to allow root login with SSH keys, but not with a password. Other users however can SSH via passwords
- You can do that using these steps
3. Regularly Update Software and System Packages #
a. Keep System Packages Up to Date
- Regularly update the system to ensure all security patches are applied.
- If you use Ubuntu/Debian, you can use this command
sudo apt update && sudo apt upgrade- If you use CentOS, Almalinux or any RHEL based distros, you can use the commands below
sudo yum update && sudo yum upgrade- Enable automatic updates for critical security patches.
b. Update and Secure All Applications
- Regularly update software like web servers, databases, and applications running on the server.
- Uninstall unused or outdated software.
4. Restrict Access to the Server #
a. Configure a Firewall
- Use a firewall to restrict access to essential services (e.g., SSH, web services).
- Use iptables, UFW (Uncomplicated Firewall), or Firewalld to configure your firewall rules.
- You could regularly review and update firewall settings to address new security threats and changes in network or server configuration
b. Disable Unnecessary Ports and Services
- Close all non-essential ports by disabling unused services and applications.
c. Limit SSH Access
- Change the default SSH port from 22 to something less common (e.g., 2222).
- Allow only specific IP addresses to access SSH using the firewall or hosts.allow file.
5. Use Security Tools #
a. Install Fail2Ban
- Fail2Ban blocks IP addresses with multiple failed login attempts, providing protection against brute-force attacks. You may refer to this guide on how to secure a server with fail2ban
b. Use Anti-Malware/Antivirus Tools
- Install and configure antivirus software like ClamAV to regularly scan your server for malware.
6. Monitor and Log Server Activity #
a. Use Intrusion Detection Systems (IDS)
- IDS is a systems that detect unusual activities that could indicate a security breach or an attack that is ongoing. Please check this article about them.
- You could use IDS to monitor and analyze network traffic to detect unauthorized activities and possible threats on your server.
b. Enable Logging and Monitoring
- Ensure all critical services log their activities and regularly review these logs for any suspicious activity
- Then as mentioned earlier, you can use tools like Fail2Ban to block IPs with failed login attempts.
c. Monitor System Resources
- Regularly monitor CPU, memory, and disk usage to identify unusual patterns that could indicate an attack.
There are more practices that can be put in place to secure servers. This article has captures juts a few of them. Implementing what has been captured in this article will go a long way to secure your server from threats.