System-Assigned Managed Identities for Azure Functions

ID: azure-functionapp-system-assigned-missing

Severity: medium

Author: princechaddha

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

Description

Ensure that functions managed with Azure Function App are using system-assigned managed identities in order to allow secure application access to other Microsoft Azure cloud resources such as SQL databases, storage accounts, and key vaults. Using system-assigned managed identities minimizes risks, simplifies management, and maintains compliance with evolving Azure cloud services.

YAML Source

id: azure-functionapp-system-assigned-missing
info:
  name: System-Assigned Managed Identities for Azure Functions
  author: princechaddha
  severity: medium
  description: |
    Ensure that functions managed with Azure Function App are using system-assigned managed identities in order to allow secure application access to other Microsoft Azure cloud resources such as SQL databases, storage accounts, and key vaults. Using system-assigned managed identities minimizes risks, simplifies management, and maintains compliance with evolving Azure cloud services.
  impact: |
    Not using system-assigned managed identities may expose Azure Function Apps to security risks and compliance issues, complicating resource access management.
  remediation: |
    Enable system-assigned managed identities for your Azure Function Apps to enhance security and simplify the management of resource access.
  reference:
    - https://docs.microsoft.com/en-us/azure/app-service/overview-managed-identity
  tags: cloud,devops,azure,microsoft,functionapp,azure-cloud-config

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

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

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

  - engine:
      - sh
      - bash
    source: |
      az functionapp show --name $name --resource-group $resourceGroup --query 'identity.type' --output json

    matchers:
      - type: word
        words:
          - ""
          - "UserAssigned"

    extractors:
      - type: dsl
        dsl:
          - 'name + " does not use system-assigned managed identity"'
# digest: 490a00463044022051170a0867a3f69854b192581a05c51ccddb5197fa02ba2e5cfcaedf1a1ef0a302200f3e5446b58fe23453d54a6b9a0c3425788a44253c11b85cb3c7fdbb9a1e8433:922c64590222798bb761d5b6d8e72950

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/functions/azure-functionapp-system-assigned-missing.yaml"

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