huntrule

FortiGate: Addition of VPN SSL Web Portal via Event Logs

Detects FortiGate configuration events where a VPN SSL web portal is added.

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

Initial Access → 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 flags FortiGate events where a VPN SSL Web Portal configuration is added. Adding a web portal can establish or extend VPN access paths and may support persistence or initial access if performed by an unauthorized actor. It relies on FortiGate event telemetry indicating an 'Add' action for the vpn.ssl.web.portal configuration path.

Reporting behind it

Related detections9 linkedT1133 — drag to rearrange
SplashTop Network
Suspicious SoftEther VPN Hamcore Config Written to ProgramData (via file_event)
SplashTop Process
AnyDesk Network
OpenCanary RDP New Connection Attempt on Application Logtype 14001
ArcSOC.exe Creates Suspicious Script/Executable Files on Windows
FortiGate SSL VPN Settings Edited
Windows Process Creation: GoAnywhere child command execution indicating possible MFT exploitation
TeamViewer Remote Session Startup Command Execution on Linux
FortiGate: Addition of VPN SSL Web Portal via Event Logs
Pivot detection · T1133 · 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.