Top 10 Ports to Secure on VPS CentOS 8 to Prevent Cyber Attacks

In today’s complex network environment, secure ports on a VPS CentOS 8 is crucial to minimize the risk of attacks. Below is a list of the Top 10 Ports to Secure on VPS CentOS 8 to Prevent Cyber Attacks.

1. Port 22 (SSH)

• Purpose: Remote connection via SSH to manage the VPS.

• Risk: Often targeted by hackers with brute force attacks to guess passwords.

• How to Secure:

Change the SSH Port:

• Open the SSH configuration file: sudo nano /etc/ssh/sshd_config
• Find the line #Port 22, remove the #, and replace it with another port number, e.g.,: Port 2222
• Restart the SSH service: sudo systemctl restart sshd
• Update the firewall to open the new port:

sudo firewall-cmd --permanent --add-port=2222/tcp

sudo firewall-cmd --remove-port=22/tcp

sudo firewall-cmd --reload

Install Fail2Ban:

• Install Fail2Ban:

sudo dnf install fail2ban

• Configure Fail2Ban to protect SSH by creating or editing the /etc/fail2ban/jail.local file.
• Restart Fail2Ban:

sudo systemctl restart fail2ban

Articles that may interest you: How to install and configure Fail2ban on Ubuntu 20.04 VPS

2. Port 80 (HTTP)

• Purpose: Serving websites via the HTTP protocol.

• Risk: Vulnerable to HTTP injection attacks or DDoS attacks.

• How to Secure:

Switch to HTTPS: Install SSL/TLS using Certbot:

sudo dnf install certbot python3-certbot-nginx

sudo certbot --nginx

Leverage Cloudflare: Use Cloudflare to mitigate DDoS attacks.

3. Port 443 (HTTPS)

• Purpose: HTTPS ensures secure encrypted data transmission.

• Risk: Resource exploitation through SSL stripping or DDoS attacks.

• How to Secure:

  • Deploy a trusted SSL/TLS certificate.
  • Use a Web Application Firewall (WAF) to protect the application layer.

4. Port 3306 (MySQL)

• Purpose: Access to the MySQL database.

• Risk: Exploited through SQL injection or brute force attacks.

• How to Secure:

Allow connections only from localhost: Edit /etc/my.cnf and add the line:

bind-address = 127.0.0.1

Restart MySQL:

sudo systemctl restart mysqld

Use strong passwords and enable SSL for connections.

5. Port 3389 (RDP)

• Purpose: Remote Desktop Protocol for Windows Servers.

• Risk: Susceptible to brute force or man-in-the-middle attacks.

• How to Secure:

Change the default port:

sudo firewall-cmd --permanent --add-port=3390/tcp

sudo firewall-cmd --reload

Implement a VPN to secure remote sessions.

6. Port 21 (FTP)

• Purpose: File transfer via FTP protocol.

• Risk: Vulnerable to eavesdropping due to lack of encryption.

• How to Secure: Use SFTP (via port 22) or FTPS instead of plain FTP.

7. Port 25 (SMTP)

• Purpose: Sending emails via the SMTP protocol.

• Risk: Exploited for spamming or relay attacks.

• How to Secure:

  • Restrict SMTP access to authorized IPs.
  • Configure SPF, DKIM, and DMARC to authenticate emails.

8. Port 53 (DNS)

• Purpose: Resolving domain names to IP addresses.

• Risk: Exploited in DNS amplification attacks.

• How to Secure:

  • Disable DNS recursion on unnecessary servers.

9. Port 6379 (Redis)

• Purpose: Connecting to the Redis database.

• Risk: Exposed to unauthorized access due to the lack of authentication by default.

• How to Secure:

Set a password in /etc/redis/redis.conf:

requirepass StrongPassword

Restrict access to localhost:

bind 127.0.0.1

Restart Redis:

sudo systemctl restart redis

10. Port 123 (NTP)

• Purpose: Synchronizing time via Network Time Protocol (NTP).

• Risk: Exploited in NTP amplification attacks.

• How to Secure:

Disable the monlist feature: Edit /etc/ntp.conf and add the line:

disable monitor

Restart the NTP service:

sudo systemctl restart ntpd

Conclusion

Secure ports on VPS CentOS 8 is essential to prevent cyber attacks. Use firewalls, authentication mechanisms, and tools like Fail2Ban to enhance the security of your VPS CentOS 8.

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