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Imagine your house with all the doors and windows wide open. While convenient for easy access, it also presents a clear security risk. Similarly, leaving open ports on your computer or network creates vulnerabilities that malicious actors can exploit.

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What Are Ports?

Think of ports as numbered doorways in your digital world. Each port corresponds to a specific service or application, allowing data to flow through for its intended purpose. For example, port 80 is commonly used for web browsing, while port 22 is used for secure shell access. You can access the list of open ports that are visible to the outside world by running a Telivy External Assessment or a Risk Assessment.

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Why Are Open Ports Bad And Why Should You Close Them?

While necessary for certain functions, open ports present several security risks:
Open ports are like open doors: they offer more entry points for attackers to probe and exploit vulnerabilities. The more ports open, the greater the attack surface and the risk of compromise.
Hackers can scan for open ports and use known vulnerabilities in the services running on those ports to gain unauthorized access. Unpatched software or outdated configurations further exacerbate this risk.
Open ports can be used to install malware onto your system, potentially leading to data theft, identity theft, or even remote control of your device.
Even unused open ports can consume system resources, making your device slower and more susceptible to performance issues.

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High-Risk Ports (Close Unless Absolutely Necessary)

Used by Windows for RPC service location and legacy NetBIOS name resolution. A common target for remote exploitation and worm propagation. Restrict to trusted networks or disable if not needed.
Allows remote access to desktops, requires strong password and proper configuration. Consider alternative remote access solutions with better security practices.
Used for accessing a database. Make sure there are proper access controls and strong passwords with MFA are used. Try avoiding public access to these ports.

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Medium-Risk Ports (Use With Caution)

Used for file and printer sharing in older Windows systems. Often exploited by malware for lateral movement. Disable if not needed, or restrict to trusted internal networks.

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Low-Risk Ports (Lower Priority, But Still Worth Reviewing)

Used for file transfer, but known for security vulnerabilities and lack of encryption. Telivy rates an open FTP port as low severity, but it’s still worth replacing with secure alternatives like SFTP (22) or FTPS (990).
Unencrypted remote access protocol. Telivy rates it low severity, but SSH (22) is the safer choice for remote access.
Secure web browsing, essential for online transactions and secure communication.
Virtual Private Network, encrypts internet traffic for secure remote access. Choose reputable VPN providers and follow best practices.
Used for online gaming, often require specific ports open depending on the game. Research necessary ports before opening them.

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How Telivy Scores Open Ports

When you run a Telivy External Assessment, each open port it finds is checked against the table above and assigned the matching severity (high, medium, or low) based on the service most commonly associated with that port. A Risk Assessment (device-based scan) works differently. Open ports found on a device are reported together as a single Device Open Ports Detected finding at one flat severity, rather than being broken out and scored port-by-port the way External Assessment results are. A few common ports aren’t part of the open-port severity table at all. SSH (22), DNS (53), HTTP (80), and HTTPS (443) are expected to be open on most servers and aren’t flagged as open-port findings on their own. SMTP (25) is evaluated separately: Telivy checks whether your mail service uses SSL/TLS encryption and reports missing encryption as its own finding, rather than treating an open SMTP port as a port-severity issue.

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How To Close Unused Ports

The process of closing unused ports depends on your specific device or network configuration. The first step is to use a port scanner like Telivy to identify which ports are open on your network. Next, understand the purpose of the ports and close the service behind the ports if you don’t need them.