Unrestricted UDP Access in Azure NSGs

ID: azure-nsg-udp-unrestricted

Severity: high

Author: princechaddha

Tags: cloud,devops,azure,microsoft,nsg,azure-cloud-config

Description

Ensure that Microsoft Azure network security groups (NSGs) do not allow unrestricted inbound access on UDP ports to prevent unauthorized access and potential exploitation of vulnerabilities.

YAML Source

id: azure-nsg-udp-unrestricted
info:
  name: Unrestricted UDP Access in Azure NSGs
  author: princechaddha
  severity: high
  description: |
    Ensure that Microsoft Azure network security groups (NSGs) do not allow unrestricted inbound access on UDP ports to prevent unauthorized access and potential exploitation of vulnerabilities.
  impact: |
    Allowing unrestricted access on UDP ports can expose network resources to various types of cyber attacks, including DDoS attacks and data exfiltration.
  remediation: |
    Restrict access to UDP ports by configuring NSG rules to only allow trusted sources and necessary traffic. Implement additional security measures where possible.
  reference:
    - https://docs.microsoft.com/en-us/azure/virtual-network/network-security-groups-overview
  tags: cloud,devops,azure,microsoft,nsg,azure-cloud-config

flow: |
  code(1);
  for (let NsgData of iterate(template.nsgdata)) {
    NsgData = JSON.parse(NsgData)
    set("nsg", NsgData.name)
    set("resourcegroup", NsgData.resourceGroup)
    code(2)
  }

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      az network nsg list --query '[*].{name:name, resourceGroup:resourceGroup}' --output json

    extractors:
      - type: json
        name: nsgdata
        internal: true
        json:
          - '.[]'

  - engine:
      - sh
      - bash
    source: |
      az network nsg rule list --nsg-name $nsg --resource-group $resourcegroup --query "[?direction=='Inbound' && access=='Allow' && protocol=='UDP']"

    matchers:
      - type: word
        words:
          - '"sourceAddressPrefix": "*"'
          - '"sourceAddressPrefix": "internet"'
          - '"sourceAddressPrefix": "any"'

    extractors:
      - type: dsl
        dsl:
          - 'nsg + " has unrestricted access on UDP ports"'
# digest: 490a004630440220479c5e2619d3075f930464189966765a8c6214f1d5627837077dfa3bf6fc478f022018bb56ac10f03fcfad227b5d30456c4218b84af0a45a7b2bc0f5406d29fb3ff9:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "cloud/azure/network/azure-nsg-udp-unrestricted.yaml"

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