Ensure there is no unrestricted inbound access to TCP port 1433 (MSSQL)

Security & Compliance

TCP port 1433 is used by Microsoft SQL Server to listen for incoming connections from client applications. It is used for both standard SQL Server connections as well as connections using the SQL Server Browser Service. If unrestricted inbound access to TCP port 1433 is allowed, it can expose the SQL Server to unauthorized access, data theft, and other security risks.


To remediate the issue of unrestricted inbound access to TCP port 1433 (MSSQL), the following steps can be taken:

  1. Verify the necessity of opening port 1433: Ensure that there is a legitimate business need for the port to be open. If there is no legitimate reason, the port should be closed.
  2. Restrict inbound access: Configure the firewall to restrict inbound traffic to the MSSQL server to only the required IP addresses or subnets. This can be done by creating a firewall rule that allows traffic to port 1433 only from approved sources.
  3. Disable unnecessary services: Disable any unnecessary services or applications that might be running on the MSSQL server.
  4. Use encryption: Use encryption to secure the connection between the client and the MSSQL server. This can be done by configuring MSSQL to use SSL/TLS encryption for connections.
  5. Keep MSSQL server updated: Keep the MSSQL server updated with the latest security patches and updates to prevent known vulnerabilities from being exploited.
  6. Monitor and log activity: Configure the MSSQL server to log all connections and activities to detect any suspicious activity or attempts to connect to the server via port 1433.
  7. Regularly review and update firewall rules: Regularly review and update the firewall rules to ensure that they are still effective and to identify any new threats or vulnerabilities.
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.