Open NetBIOS
Determines if UDP port 137, 138 or 139 for NetBIOS is open to the public
While some ports such as HTTP and HTTPS are required to be open to the public to function properly, more sensitive services such as NetBIOS should be restricted to known IP addresses.
Recommended Actions
Follow the appropriate remediation steps below to resolve the issue.
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Log into the Google Cloud Platform Console.
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Scroll down the left navigation panel and choose the “Networking” to select the “Firewall rules” option under the “VPC network.”
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On the “Firewall rules” page, select the “Firewall rule” which needs to be verified.
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On the selected “Firewall rules”, if UDP port 137 or 138 for “NetBIOS” are open to the public then the selected “Firewall rule” is not as per the best standards.
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Repeat steps number 2 - 4 to verify another “Firewall rule” in the network.
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Navigate to “VPC network” and choose the “Firewall rules” option under the “Networking” and select the “Firewall rule” which needs to be restricted to known IP addresses.
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On the “Firewall rules” page, click on the “Edit” button at the top and under the “Source IP ranges” enter the IP addresses as per the requirements.
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Click on the “Save” button at the bottom to make the changes.
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Repeat steps number 6 - 8 to restrict UDP ports 137 and 138 to known IP addresses.