Network misconfigurations

Elastic Load Balancer (ELB) allows ingress access to NetBIOS port 139

Platform(s)
Compliance Frameworks
  • CCPA
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  • Mitre ATT&CK
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  • New Zealand Information Security Manual
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  • NIST 800-171
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  • NIST 800-53
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  • Orca Best Practices
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  • UK Cyber Essentials

Description

NetBIOS port 139 is used for Network file sharing and shared printer in the LAN. Allowing inbound traffic from all external IP addresses to NetBIOS ports can be risky as your shared resources are exposed over the public internet. It is a best practice to block port 139 completely.