Sigma rule: FortiGate - User Group Modified

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-8d92c2466a26, updated 2025-11-01T00:00:00.000Z.

Rule

Title
FortiGate - User Group Modified
Status
experimental
Level
medium
Author
Marco Pedrinazzi (@pedrinazziM) (InTheCyber)
Date
2025-11-01
File
rules/network/fortinet/fortigate/fortinet_fortigate_user_group_modified.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the modification of a user group on a Fortinet FortiGate Firewall.
The group could be used to grant VPN access to a network.

Log source

product
fortigate
service
event

Detection

selection:
    action: 'Edit'
    cfgpath: 'user.group'
condition: selection

False positives (as the rule lists them)

  • A group can be modified for legitimate purposes.

Tags

  • attack.persistence
  • attack.privilege-escalation

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/network/fortinet/fortigate/fortinet_fortigate_user_group_modified.yml

Sources and licences

  • SigmaHQ

    "FortiGate - User Group Modified" by Marco Pedrinazzi (@pedrinazziM) (InTheCyber) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/network/fortinet/fortigate/fortinet_fortigate_user_group_modified.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: FortiGate - User Group Modified",
entity page, dataset version ref-8d92c2466a26, updated 2025-11-01T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/69ffc84e-8b1a-4024-8351-e018f66b8275 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 69ffc84e-8b1a-4024-8351-e018f66b8275, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.