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Ensure there is no unrestricted inbound access to TCP port 53 (DNS)

Security & Compliance

Ensure there is no unrestricted inbound access to TCP port 53 (DNS) refers to securing the DNS (Domain Name System) server by preventing unauthorized access to its TCP port 53. This port is commonly used for DNS queries and transfers, which makes it a common target for attackers looking to exploit vulnerabilities or conduct denial-of-service attacks. Therefore, it is important to restrict inbound access to this port to only authorized users or systems to prevent potential security breaches.


Here are some remediation steps to ensure that there is no unrestricted inbound access to TCP port 53:

  1. Implement a firewall: A firewall can be used to restrict inbound access to TCP port 53. The firewall can be configured to allow only authorized DNS servers to access this port.
  2. Configure DNS servers: Configure your DNS servers to only listen to requests from authorized sources. You can also use DNS security extensions (DNSSEC) to prevent DNS spoofing and cache poisoning attacks.
  3. Implement DNS filtering: Implement DNS filtering to block access to malicious domains and prevent attacks such as malware infections or data exfiltration.
  4. Monitor DNS traffic: Monitor DNS traffic to identify and prevent attacks in real-time. This can be done using DNS traffic analysis tools or by configuring logging and alerting systems.
  5. Keep DNS servers updated: Keep your DNS servers updated with the latest security patches and updates to prevent known vulnerabilities from being exploited.

By implementing these remediation steps, you can ensure that there is no unrestricted inbound access to TCP port 53, and prevent DNS attacks from compromising your network.

Enforced Resources
Note: Remediation steps provided by Lightlytics are meant to be suggestions and guidelines only. It is crucial to thoroughly verify and test any remediation steps before applying them to production environments. Each organization's infrastructure and security needs may differ, and blindly applying suggested remediation steps without proper testing could potentially cause unforeseen issues or vulnerabilities. Therefore, it is strongly recommended that you validate and customize any remediation steps to meet your organization's specific requirements and ensure that they align with your security policies and best practices.
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