name: User Discovery With Env Vars PowerShell
id: 0cdf318b-a0dd-47d7-b257-c621c0247de8
version: 1
date: '2021-09-13'
author: Mauricio Velazco, Splunk
status: production
type: Hunting
description: This analytic looks for the execution of `powershell.exe` with command-line
  arguments that leverage PowerShell environment variables to identify the current
  logged user. Red Teams and adversaries may leverage this method to identify the
  logged user on a compromised endpoint for situational awareness and Active Directory
  Discovery.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    CommandLine:
    - '*[System.Environment]::UserName*'
    - '*$env:UserName*'
    Image|endswith: powershell.exe
  condition: (selection1)
how_to_implement: To successfully implement this search you need to be ingesting information
  on process that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` node.
known_false_positives: Administrators or power users may use this command for troubleshooting.
references:
- https://attack.mitre.org/techniques/T1033/
tags:
  analytic_story:
  - Active Directory Discovery
  asset_type: Endpoint
  confidence: 50
  impact: 30
  message: System user discovery on $dest$
  mitre_attack_id:
  - T1033
  observable:
  - name: dest
    type: Endpoint
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 15
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1033/AD_discovery/windows-sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog