FortiGate - New Local User Created

Title: FortiGate - New Local User Created
Status: experimental
Description:Detects the creation of a new local user on a Fortinet FortiGate Firewall. The new local user could be used for VPN connections.
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/109120963/config-user-local
  -https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/44547/44547-logid-event-config-objattr
Author: Marco Pedrinazzi (@pedrinazziM) (InTheCyber)
Date: 2025-11-01
modified:None
Tags:

• -'attack.persistence'
• -'attack.t1136.001'

Logsource:

• product: fortigate
• service: event

Detection:
  selection:
    action: 'Add'
    cfgpath: 'user.local'
  condition:selection
Falsepositives:
  -A local user can be created for legitimate purposes. Investigate the user details to determine if it is authorized.
Level: medium