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FortiGate - New VPN SSL Web Portal Added — Sigma Rule

Sigma rule 2bfb6216-0c31-4d20-8501-2629b29a3fa2. FortiGate - New VPN SSL Web Portal Added — Sigma Rule. Detects the addition of a VPN SSL Web Portal on a Fortinet FortiGate Firewall. This behavior was observed in pair with modification of VPN SSL settings.

Rule metadata and linked tags

experimentalmediumfortigateeventattack.persistenceattack.initial-accessattack.t1133

Author: Marco Pedrinazzi @pedrinazziM (InTheCyber). Source status: experimental; severity: medium. Source dates: 2025-11-01 / not supplied.

{
  "product": "fortigate",
  "service": "event"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 9ba53397da448b863fc48bd05d8574afc23a1f9e6861dbd87c8ee2cc09d416de

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: FortiGate - New VPN SSL Web Portal Added
id: 2bfb6216-0c31-4d20-8501-2629b29a3fa2
status: experimental
description: |
    Detects the addition of a VPN SSL Web Portal on a Fortinet FortiGate Firewall.
    This behavior was observed in pair with modification of VPN SSL settings.
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/113121765/config-vpn-ssl-web-portal
    - 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
tags:
    - attack.persistence
    - attack.initial-access
    - attack.t1133
logsource:
    product: fortigate
    service: event
detection:
    selection:
        action: 'Add'
        cfgpath: 'vpn.ssl.web.portal'
    condition: selection
falsepositives:
    - A VPN SSL Web Portal can be added for legitimate purposes.
level: medium

Original YAML and metadata in JSON

False positives

  • A VPN SSL Web Portal can be added for legitimate purposes.

Source references

Connected ecosystem references

Exact source-tagged techniques

Telemetry review

Read the original logsource above, then inspect the linked detection workspaces for technique-level sensor context. No per-rule telemetry equivalence is inferred.

Pinned research references. No browser attack runner, live simulation result or validated detector is asserted. Source mappings and validation limits are preserved. ATT&CK / Atomic provenance · Detection provenance.