List of Dangerous Open Ports
Port: 21
Explanation: This port is used for FTP (File Transfer Protocol).
Impact: This port sends its data over plain text, meaning that attackers can abuse this port to intercept and steal credentials.
Mitigation: Close port 21.
- Windows: Go to Windows Firewall settings and block port 21.
- Linux: Use the command
sudo ufw deny 21to close this port.
Port: 22
Explanation: This port is used for SSH (Secure Shell).
Impact: If not properly secured, this port can be exploited by attackers to gain unauthorized access to the system.
Mitigation: Secure port 22 by using strong authentication methods, or close it if not in use.
- Windows: Go to Windows Firewall settings and block port 22 if not required.
- Linux: Use the command
sudo ufw deny 22to close this port.
Port: 23
Explanation: This port is used for Telnet.
Impact: Telnet sends its data, including passwords, over plain text, making it vulnerable to eavesdropping.
Mitigation: Close port 23 and use SSH instead.
- Windows: Disable Telnet services and block port 23 in Windows Firewall.
- Linux: Use
sudo ufw deny 23to block this port.
Port: 25
Explanation: This port is used for SMTP (Simple Mail Transfer Protocol).
Impact: Attackers can exploit this port to send spam or phishing emails if not properly secured.
Mitigation: Secure port 25 with proper authentication and spam filtering.
- Windows: Configure mail server settings to require authentication.
- Linux: Use firewall rules to restrict access to port 25.
Port: 53
Explanation: This port is used for DNS (Domain Name System).
Impact: Open DNS ports can be exploited for DNS amplification attacks.
Mitigation: Secure port 53 by configuring DNS servers to prevent open recursion.
- Windows: Configure DNS services to only allow trusted networks.
- Linux: Use
sudo ufw allow from trusted_ips to any port 53.
Port: 80
Explanation: This port is used for HTTP (Hypertext Transfer Protocol).
Impact: HTTP traffic is unencrypted, making it susceptible to eavesdropping and man-in-the-middle attacks.
Mitigation: Redirect HTTP traffic to HTTPS (port 443).
- Windows: Configure web server settings to redirect traffic from port 80 to 443.
- Linux: Use firewall rules to enforce HTTPS and redirect HTTP traffic.