What is an Open Port? Risky Ports You Need to Close Immediately
In networking, a port is a virtual point where network connections start and end. An open port is a port configured to accept incoming packets. While essential for services like web browsing, unmonitored open ports are a major entry point for siber attacks.
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Top Dangerous Ports Exposed to the Internet
You must check if your digital perimeter is exposing any of these high-risk ports:
- Port 22 (SSH): Used for secure server logins. If exposed to the internet, attackers will run brute-force scripts to guess credentials.
- Port 3389 (RDP): Microsoft Remote Desktop. Vulnerable to remote code execution (RCE) and password attacks.
- Port 5432 (PostgreSQL) / Port 3306 (MySQL): Database ports. Should never be open to the internet. Access should be restricted via a VPN or localhost.
- Port 6379 (Redis) / Port 9200 (Elasticsearch): In-memory data structures. Frequently run without passwords by default, allowing instant database dumps.
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How to Secure Exposed Ports
1. Firewall Rules: Block all incoming traffic by default, allowing only Port 80 and 443. 2. Use VPN / Bastion Hosts: For remote administration, access servers only through a secure virtual private network. 3. Continuous Scanning: Periodically check your IP blocks to make sure developers didn't temporarily open a port for testing and forget to close it.
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Identify Your Exposed Ports with Mangudai
Mangudai automatically scans your target domains and IP blocks for open ports. If a database port or administration service is discovered, it raises a critical alert immediately.
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