Fortinet Appliance Auth bypass

name: Fortinet Appliance Auth bypass
id: a83122f2-fa09-4868-a230-544dbc54bc1c
version: 8
date: '2026-03-23'
author: Michael Haag, Splunk
status: production
type: TTP
description: |
    The following analytic detects attempts to exploit CVE-2022-40684, a Fortinet appliance authentication bypass vulnerability.
    It identifies REST API requests to the /api/v2/ endpoint using various HTTP methods (GET, POST, PUT, DELETE) that may indicate unauthorized modifications, such as adding SSH keys or creating new users.
    This detection leverages the Web datamodel to monitor specific URL patterns and HTTP methods.
    This activity is significant as it can lead to unauthorized access and control over the appliance.
    If confirmed malicious, attackers could gain persistent access, reroute network traffic, or capture sensitive information.
data_source:
    - Palo Alto Network Threat
search: |-
    | tstats `security_content_summariesonly`
             count min(_time) as firstTime
                   max(_time) as lastTime

    FROM datamodel=Web WHERE

    Web.url = "*/api/v2/cmdb/system/admin*"
    Web.http_method IN ("GET", "PUT")
    BY Web.http_user_agent
       Web.http_method Web.url
       Web.url_length
       Web.src Web.dest
    | `drop_dm_object_name("Web")`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `fortinet_appliance_auth_bypass_filter`
how_to_implement: |
    This detection requires the Web datamodel to be populated from a supported Technology Add-On like Splunk for Apache. Splunk for Nginx, or Splunk for Palo Alto.
known_false_positives: |
    GET requests will be noisy and need to be filtered out or removed from the query based on volume.
    Restrict analytic to known publicly facing Fortigates, or run analytic as a Hunt until properly tuned.
    It is also possible the user agent may be filtered on Report Runner or Node.js only for the exploit, however, it is unknown at this if other user agents may be used.
references:
    - https://www.wordfence.com/blog/2022/10/threat-advisory-cve-2022-40684-fortinet-appliance-auth-bypass/
    - https://www.horizon3.ai/fortios-fortiproxy-and-fortiswitchmanager-authentication-bypass-technical-deep-dive-cve-2022-40684/
    - https://github.com/horizon3ai/CVE-2022-40684
    - https://www.horizon3.ai/fortinet-iocs-cve-2022-40684/
    - https://attackerkb.com/topics/QWOxGIKkGx/cve-2022-40684/rapid7-analysis
    - https://github.com/rapid7/metasploit-framework/pull/17143
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: Potential CVE-2022-40684 against a Fortinet appliance may be occurring against $dest$.
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects: []
tags:
    analytic_story:
        - CVE-2022-40684 Fortinet Appliance Auth bypass
    asset_type: Network
    cve:
        - CVE-2022-40684
    mitre_attack_id:
        - T1190
        - T1133
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: network
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/fortigate/fortinetcve202240684.log
          source: not_applicable
          sourcetype: pan:threat