Closing Security Vulnerabilities in Linux Hosting: Firewall, DDoS, and WAF Installati...

Introduction

Security in Linux hosting environments is one of the most critical aspects of server management. In this article, we will provide a step-by-step guide to closing security vulnerabilities.

Detecting Security Issues

First, we need to use some commands to identify existing security issues:

• top - Monitors the server's real-time performance. Check CPU and memory usage.
• htop - Provides a more visual interface to monitor processes. Identify processes consuming high resources.
• dmesg - Checks kernel and system errors. Can provide information about security vulnerabilities.
• netstat -tuln - Lists active connections and listening ports.
• iptables -L - Displays current firewall rules.

Firewall Installation

A firewall is the first line of defense for your server. Steps to install UFW (Uncomplicated Firewall):

1. Install UFW: sudo apt install ufw
2. Enable UFW: sudo ufw enable
3. Open necessary ports: sudo ufw allow 22/tcp (for SSH) and sudo ufw allow 80/tcp (for HTTP).
4. Check rules: sudo ufw status

DDoS Protection

To protect against DDoS attacks, follow these steps:

1. Install Fail2ban: sudo apt install fail2ban
2. Edit Fail2ban configuration: sudo nano /etc/fail2ban/jail.local and add the following settings:

[sshd] 
 enabled = true 
 port = 22 
 filter = sshd 
 logpath = /var/log/auth.log 
 maxretry = 5 
 bantime = 3600

3. Start Fail2ban service: sudo systemctl start fail2ban

Web Application Firewall (WAF) Installation

It is essential to install a WAF to enhance web application security. You can start with ModSecurity:

1. Install ModSecurity for Apache: sudo apt install libapache2-mod-security2
2. Enable ModSecurity: sudo a2enmod security2
3. Edit the configuration file: sudo nano /etc/modsecurity/modsecurity.conf and set SecRuleEngine On.
4. Restart Apache: sudo systemctl restart apache2

Conclusion

By following the steps above, you can significantly enhance the security of your Linux hosting server. Security is an ongoing process; therefore, regularly check for updates and review your security policies.