Whoami.EXE Execution Anomaly — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: medium. Source dates: 2021-08-12 / 2025-03-06.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 07a23606d2d8234926302a9aa167be225bf48ecd4ed21d1938c30a63a1ffdbeb

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: Whoami.EXE Execution Anomaly
id: 8de1cbe8-d6f5-496d-8237-5f44a721c7a0
status: test
description: Detects the execution of whoami.exe with suspicious parent processes.
references:
    - https://brica.de/alerts/alert/public/1247926/agent-tesla-keylogger-delivered-inside-a-power-iso-daa-archive/
    - https://app.any.run/tasks/7eaba74e-c1ea-400f-9c17-5e30eee89906/
    - https://www.youtube.com/watch?v=DsJ9ByX84o4&t=6s
author: Florian Roth (Nextron Systems)
date: 2021-08-12
modified: 2025-03-06
tags:
    - attack.discovery
    - attack.t1033
    - car.2016-03-001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        - Image|endswith: '\whoami.exe'
        - OriginalFileName: 'whoami.exe'
    filter_main_known_parents:
        # This list can be any legitimate shell or application that you expect whoami to run from
        ParentImage|endswith:
            - '\cmd.exe'
            - '\powershell_ise.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
    filter_optional_ms_monitoring_agent:
        ParentImage|endswith: ':\Program Files\Microsoft Monitoring Agent\Agent\MonitoringHost.exe'
    filter_main_parent_null:
        ParentImage: null
    filter_main_parent_empty:
        ParentImage:
            - ''
            - '-'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Admin activity
    - Scripts and administrative tools used in the monitored environment
    - Monitoring activity
level: medium

Original YAML and metadata in JSON

False positives

• Admin activity
• Scripts and administrative tools used in the monitored environment
• Monitoring activity

Source references

• https://brica.de/alerts/alert/public/1247926/agent-tesla-keylogger-delivered-inside-a-power-iso-daa-archive/
• https://app.any.run/tasks/7eaba74e-c1ea-400f-9c17-5e30eee89906/
• https://www.youtube.com/watch?v=DsJ9ByX84o4&t=6s