Airflow Experimental <1.10.11 - REST API Auth Bypass

Exploited in the wild. Listed by CISA on 2022-01-18; known to be used by ransomware.

criticalseverity

9.8CVSS score

99.8%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

Airflow's Experimental API prior 1.10.11 allows all API requests without authentication.

Impact

Allows unauthorized access to Airflow Experimental REST API

Fix

From Airflow 1.10.11 forward, the default has been changed to deny all requests by default. Note - this change fixes it for new installs but existing users need to change their config to default `[api]auth_backend = airflow.api.auth.backend.deny_all` as mentioned in the Updating Guide linked in the references.

How to confirm it

Send: GET {{BaseURL}}/api/experimental/latest_runs
Positive when: contains "\"dag_run_url\":" and "\"dag_id\":" and "\"items\":"

Run it with nuclei: nuclei -id CVE-2020-13927 -u <target>

The full check

id: CVE-2020-13927

info:
  name: Airflow Experimental <1.10.11 - REST API Auth Bypass
  author: pdteam
  severity: critical
  description: |
    Airflow's Experimental API prior 1.10.11 allows all API requests without authentication.
  impact: |
    Allows unauthorized access to Airflow Experimental REST API
  remediation: |
    From Airflow 1.10.11 forward, the default has been changed to deny all requests by default.  Note - this change fixes it for new installs but existing users need to change their config to default `[api]auth_backend = airflow.api.auth.backend.deny_all` as mentioned in the Updating Guide linked in the references.
  reference:
    - https://lists.apache.org/thread.html/r23a81b247aa346ff193670be565b2b8ea4b17ddbc7a35fc099c1aadd%40%3Cdev.airflow.apache.org%3E
    - http://packetstormsecurity.com/files/162908/Apache-Airflow-1.10.10-Remote-Code-Execution.html
    - https://airflow.apache.org/docs/1.10.11/security.html#api-authenticatio
    - https://nvd.nist.gov/vuln/detail/CVE-2020-13927
    - http://packetstormsecurity.com/files/174764/Apache-Airflow-1.10.10-Remote-Code-Execution.html
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2020-13927
    cwe-id: CWE-1188
    epss-score: 0.99778
    epss-percentile: 0.99955
    cpe: cpe:2.3:a:apache:airflow:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: apache
    product: airflow
    shodan-query:
      - title:"Airflow - DAGs" || http.html:"Apache Airflow"
      - http.title:"airflow - dags" || http.html:"apache airflow"
      - http.title:"sign in - airflow"
      - product:"redis"
    fofa-query:
      - title="sign in - airflow"
      - apache airflow
      - title="airflow - dags" || http.html:"apache airflow"
    google-query:
      - intitle:"sign in - airflow"
      - intitle:"airflow - dags" || http.html:"apache airflow"
  tags: cve2020,cve,packetstorm,apache,airflow,unauth,auth-bypass,kev,vkev,vuln

http:
  - method: GET
    path:
      - '{{BaseURL}}/api/experimental/latest_runs'

    matchers:
      - type: word
        part: body
        words:
          - '"dag_run_url":'
          - '"dag_id":'
          - '"items":'
        condition: and

References

Use this check only on systems you are authorised to test. Where the data comes from