huntrule

FortiGate SSL VPN Settings Edited

Flags FortiGate VPN SSL settings being edited, which may indicate changes to SSL VPN access or authentication configuration.

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 SSL VPN settings are edited, specifically changes under vpn.ssl.settings. Attackers may modify SSL VPN authentication-related configuration to establish or maintain remote access persistence. It relies on FortiGate event telemetry capturing an Edit action and the targeted configuration path.

Reporting behind it

Related detections9 linkedT1133 — drag to rearrange
Suspicious Reverse SSH Tunnel Creation with Host Key Verification Disabled (via process_creation)
Suspicious Shell Script Execution From Temp Directory on SonicWall SMA1000 Appliance (via process_creation)
Possible PAN-OS CVE-2026-0257 Exploitation via GlobalProtect PoC Artifacts (via network)
Possible RD Web Access Brute Force via Repeated Login POST Requests
Suspicious Security Group Ingress Rule Opened to the Internet via CloudTrail
SplashTop Network
Suspicious SoftEther VPN Hamcore Config Written to ProgramData (via file_event)
SplashTop Process
AnyDesk Network
FortiGate SSL VPN Settings Edited
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.