OS Login with 2FA Authentication Not Enabled for VM Instances

ID: gcloud-vm-oslogin-2fa-disabled

Severity: high

Author: princechaddha

Tags: cloud,devops,gcp,gcloud,compute,security,2fa,gcp-cloud-config

Description

Ensure that the OS Login feature enabled at the virtual machine instance level is configured with Two-Factor Authentication (2FA) in order to help protect the access to your Google Cloud VM instances. Two-Factor Authentication (also known as Multi-Factor Authentication - MFA) provides an additional layer of security on top of the existing credentials.

YAML Source

id: gcloud-vm-oslogin-2fa-disabled

info:
  name: OS Login with 2FA Authentication Not Enabled for VM Instances
  author: princechaddha
  severity: high
  description: |
    Ensure that the OS Login feature enabled at the virtual machine instance level is configured with Two-Factor Authentication (2FA) in order to help protect the access to your Google Cloud VM instances. Two-Factor Authentication (also known as Multi-Factor Authentication - MFA) provides an additional layer of security on top of the existing credentials.
  impact: |
    Without 2FA enabled for OS Login, VM instances are more vulnerable to unauthorized access through compromised credentials.
  remediation: |
    Enable OS Login with 2FA authentication for all VM instances by setting the "enable-oslogin-2fa" metadata key to "TRUE".
  reference:
    - https://cloud.google.com/compute/docs/oslogin/set-up-oslogin
  tags: cloud,devops,gcp,gcloud,compute,security,2fa,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let instance of iterate(template.instances)){
      instance = JSON.parse(instance)
      set("instanceName", instance.name)
      set("zone", instance.zone)
      code(3)
    }
  }

self-contained: true

code:
  - engine:
      - sh
      - bash
    source: |
      gcloud projects list --format="json(projectId)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute instances list --project $projectId --format="json[](name,zone.basename())"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute instances describe $instanceName --zone $zone --project $projectId --format="json(metadata.items)" | jq '.items[]? | select(.key=="enable-oslogin-2fa") | .value // "null"'

    matchers:
      - type: word
        words:
          - "FALSE"
          - "null"
        condition: or

    extractors:
      - type: dsl
        dsl:
          - '"OS Login with 2FA authentication is not enabled for VM instance " + instanceName + " in zone " + zone + " of project " + projectId'
# digest: 4b0a00483046022100ec0b0d38721c46ad2e4dc2ed7079c6e6e8bc50657cc13c48fe68d37bdbdea45502210085d925e1ae3588e7fba54299325473f2ce75a2e8d65c49dfdd57bbec92a760a9:922c64590222798bb761d5b6d8e72950

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/gcp/compute/gcloud-vm-oslogin-2fa-disabled.yaml"

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