Network security groups should limit inbound UDP port 138 access from the internet
Checks that network security group rules do not allow unrestricted inbound traffic on UDP port 138. Network security groups provide stateful filtering of inbound and outbound traffic to Azure resources, and Trivy `AZU-0047` flags ingress from any IP address.
Opening up ports to allow connections from the public internet is generally to be avoided. You should restrict access to IP addresses or ranges that are explicitly required where possible.
What this control checks
A security group rule should not allow unrestricted ingress from any IP address.
Audit evidence
Evidence that deployed resources meet this control: PowerPipe control azure_compliance.control.network_security_group_restrict_inbound_udp_port_138.
Scans of the Terraform code that flag the same setting before deployment: Trivy check AZU-0047.
Related controls
Tool mappings
Use these identifiers to cross-reference this control across tools, reports, and evidence.
- Compliance.tf Control:
network_security_group_restrict_inbound_udp_port_138 - Powerpipe Control:
azure_compliance.control.network_security_group_restrict_inbound_udp_port_138 - Trivy Check:
AZU-0047
Last reviewed: 2026-10-13