Ensure there is no unrestricted inbound access to TCP port 1434 (MSSQL)

Security & Compliance
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Ensure there is no unrestricted inbound access to TCP port 1434 (MSSQL) is a security measure to prevent unauthorized access to Microsoft SQL Server. Port 1434 is used by SQL Server Browser Service, which is responsible for managing SQL Server connections by redirecting client requests to the appropriate instance of SQL Server. Without proper restrictions, an attacker can use this port to gain unauthorized access to SQL Server.


To remediate the issue of unrestricted inbound access to TCP port 1434 (MSSQL), you can take the following steps:

  1. Identify the systems that are listening on port 1434 and ensure that they are necessary for business operations.
  2. Review the firewall rules to ensure that traffic to port 1434 is only allowed from trusted IP addresses and subnets.
  3. If necessary, update the firewall rules to block traffic to port 1434 from all external sources.
  4. Consider implementing a host-based intrusion prevention system (HIPS) or an endpoint protection solution to monitor for and prevent unauthorized access to port 1434.
  5. Apply the principle of least privilege by restricting the privileges of the user accounts and service accounts that are associated with the MSSQL instances listening on port 1434.
  6. Regularly review and update firewall rules and access control lists (ACLs) to ensure that they remain effective and up-to-date.
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.