Group Membership Reconnaissance Via Whoami.EXE — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2023-02-28 / not supplied.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 9811f214ced5d77bc91b9ba4656513fd488a4c98e25f058fd43c3b86cb190cc1

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: Group Membership Reconnaissance Via Whoami.EXE
id: bd8b828d-0dca-48e1-8a63-8a58ecf2644f
status: test
description: Detects the execution of whoami.exe with the /group command line flag to show group membership for the current user, account type, security identifiers (SID), and attributes.
references:
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/whoami
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-02-28
tags:
    - attack.discovery
    - attack.t1033
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\whoami.exe'
        - OriginalFileName: 'whoami.exe'
    selection_cli:
        CommandLine|contains:
            - ' /groups'
            - ' -groups'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/whoami