Ensure there is no unrestricted inbound access to TCP port 445 (SMB)

Security & Compliance
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TCP port 445 is used by the Server Message Block (SMB) protocol to provide shared access to files, printers, and other resources over a network. Unrestricted inbound access to this port can potentially allow attackers to gain unauthorized access to shared files and resources, or to launch SMB-related attacks such as ransomware, spyware, or malware infections.


Here are the remediation steps to ensure there is no unrestricted inbound access to TCP port 445 (SMB):

  1. Identify all systems that require access to shared resources through TCP port 445.
  2. Implement firewall rules and access control lists (ACLs) to block all incoming traffic to port 445, except for authorized hosts or IP addresses that require access to the shared resources.
  3. Disable SMB version 1, which is known to be vulnerable to various attacks, and use SMB version 2 or later.
  4. Implement SMB encryption and signing to protect against eavesdropping and tampering attacks.
  5. Enable file and printer sharing only on networks or subnets that require it, and use network segmentation to isolate shared resources from other network segments.
  6. Monitor the SMB server logs regularly to detect any unauthorized attempts to access the TCP port 445.
  7. Regularly review and update the firewall rules, access control lists, and SMB encryption and signing mechanisms to ensure they are up to date and configured correctly.

By following these remediation steps, you can ensure that shared resources are secured and that access to the TCP port 445 is restricted only to authorized sources, reducing the risk of unauthorized access, ransomware, spyware, malware infections, and other security incidents.

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.