FortiGate: Administrator Account Added via system.admin Events

Alerts on FortiGate events that add a new administrator account in system.admin.

FreeReviewedSigma · Medium · v2

Product: fortigate
Service: event
Author: Marco Pedrinazzi (@pedrinazziM) (InTheCyber) (SigmaHQ), DRL 1.1
Published: 2025-11-01
Updated: 2026-07-31

ATT&CK techniques

Persistence

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1136.001Local Account
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags FortiGate event logs indicating an administrator account was added under the system.admin configuration path. Creating or modifying admin accounts is a common persistence technique, allowing an attacker to regain access after initial compromise. The detection relies on FortiGate event telemetry containing the account-creation action and the cfgpath value for system.admin.

Reporting behind it

Related detections9 linkedT1136.001 — drag to rearrange

Suspicious Local Account Creation via Net User in Pre-Ransomware Phase

Suspicious Hidden Local Account Creation via Net User by UAT-8099

Malicious Local Account Creation of Support or Whiteninja via net.exe

Malicious Dynamicweb Unauthenticated Administrator Creation via Setup Default.aspx (via webserver)

Suspicious Hidden Backdoor Account Creation Ending With Dollar Sign (via process_creation)

Malicious User Creation via Commandline (via process_creation)

Suspicious Local Account Creation and Privileged Group Addition via Net.EXE (via process_creation)

Suspicious Hidden Local Account Creation via Dscl (via process_creation)

Suspicious Local Account Creation on Linux (via process_creation)

FortiGate: Administrator Account Added via system.admin Events

Pivot detection · T1136.001 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

fortigate-administrator-account-added-via-system-admin-event-cd0a4943

title: "FortiGate: Administrator Account Added via system.admin Events"
id: 52c6480b-f92e-43b8-8b51-b45e82abfc5c
status: experimental
description: This rule flags FortiGate event logs indicating an administrator account was added under the system.admin configuration path. Creating or modifying admin accounts is a common persistence technique, allowing an attacker to regain access after initial compromise. The detection relies on FortiGate event telemetry containing the account-creation action and the cfgpath value for system.admin.
references:
  - https://www.fortiguard.com/psirt/FG-IR-24-535
  - https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/398/event
  - https://docs.fortinet.com/document/fortigate/7.6.4/cli-reference/390485493/config-system-admin
  - https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/44547/44547-logid-event-config-objattr
  - https://github.com/SigmaHQ/sigma/blob/master/rules/network/fortinet/fortigate/fortinet_fortigate_new_admin_account_created.yml
author: Marco Pedrinazzi (@pedrinazziM) (InTheCyber), Huntrule Team
date: 2025-11-01
tags:
  - attack.persistence
  - attack.t1136.001
logsource:
  product: fortigate
  service: event
detection:
  selection:
    action: Add
    cfgpath: system.admin
  condition: selection
falsepositives:
  - An administrator account can be created for legitimate purposes. Investigate the account details to determine if it is authorized.
level: medium
license: DRL-1.1
related:
  - id: cd0a4943-0edd-42cf-b50c-06f77a10d4c1
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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