huntrule

FortiGate: Local User Added via CLI Event

Alerts on FortiGate events where a new local user is added under user.local.

FreeReviewedSigma · Medium · v2
Product
fortigate
Service
event
Author
Marco Pedrinazzi (@pedrinazziM) (InTheCyber) (SigmaHQ), DRL 1.1
Published
2025-11-01
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Persistence

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule identifies FortiGate event log entries indicating a new local user was added under user.local. Attackers may create local users to establish persistent access, including potential use for VPN authentication. It relies on FortiGate event telemetry fields where the action is "Add" and the configuration path is "user.local".

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: Local User Added via CLI Event
Pivot detection · T1136.001 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. 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.