Azure VMSS Load Balancer Unassociated

ID: azure-vmss-load-balancer-unassociated

Severity: medium

Author: princechaddha

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

Description

Ensure that each Microsoft Azure virtual machine scale set is integrated with a load balancer in order to distribute incoming traffic among healthy virtual machine instances running within the scale set. Azure load balancer is a layer 4 load balancer that provides low latency, high throughput, and scales up to millions of flows for all TCP and UDP web applications.

YAML Source

id: azure-vmss-load-balancer-unassociated
info:
  name: Azure VMSS Load Balancer Unassociated
  author: princechaddha
  severity: medium
  description: |
    Ensure that each Microsoft Azure virtual machine scale set is integrated with a load balancer in order to distribute incoming traffic among healthy virtual machine instances running within the scale set. Azure load balancer is a layer 4 load balancer that provides low latency, high throughput, and scales up to millions of flows for all TCP and UDP web applications.
  impact: |
    Virtual machine scale sets without associated load balancers may experience uneven traffic distribution and potential bottlenecks, affecting performance and reliability.
  remediation: |
    Ensure each Azure virtual machine scale set is integrated with a load balancer to distribute incoming traffic effectively among instances.
  reference:
    - https://docs.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-load-balancer
  tags: cloud,devops,azure,microsoft,vmss,azure-cloud-config

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

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

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

  - engine:
      - sh
      - bash
    source: |
      az vmss show --name "$name" --resource-group "$resourceGroup" --query 'virtualMachineProfile.networkProfile.networkInterfaceConfigurations[*].ipConfigurations[*].loadBalancerBackendAddressPools[*].id | []'

    matchers-condition: and
    matchers:
      - type: word
        words:
          - '[]'

    extractors:
      - type: dsl
        dsl:
          - 'name + " in " + resourceGroup + " is not associated with a load balancer"'
# digest: 4a0a00473045022031dff48a4dbd5c8b7b82ff855de9935b3af7a25fb08c79596f2b4b56f2d17a11022100d24fc1f6a399b268e3b6366990210974afe8c287781e2ae5dd97717f000d13f2:922c64590222798bb761d5b6d8e72950

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/virtualmachines/azure-vmss-load-balancer-unassociated.yaml"

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