name: GetCurrent User with PowerShell Script Block
id: 80879283-c30f-44f7-8471-d1381f6d437a
version: 2
date: '2022-03-22'
author: Mauricio Velazco, Splunk
status: production
type: Hunting
description: The following analytic utilizes PowerShell Script Block Logging (EventCode=4104)
  to identify the execution of the `GetCurrent` method of the WindowsIdentity .NET
  class. This method returns an object that represents the current Windows 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:
- Powershell 4104
search: '`powershell` EventCode=4104 ScriptBlockText = "*[System.Security.Principal.WindowsIdentity]*"  ScriptBlockText
  = "*GetCurrent()*" | stats count min(_time) as firstTime max(_time) as lastTime
  by EventCode ScriptBlockText Computer UserID | rename Computer as dest, UserID as user | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)` | `getcurrent_user_with_powershell_script_block_filter`'
how_to_implement: To successfully implement this analytic, you will need to enable
  PowerShell Script Block Logging on some or all endpoints. Additional setup here
  https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
known_false_positives: Administrators or power users may use this PowerShell commandlet
  for troubleshooting.
references:
- https://attack.mitre.org/techniques/T1033/
- https://docs.microsoft.com/en-us/dotnet/api/system.security.principal.windowsidentity.getcurrent?view=net-6.0&viewFallbackFrom=net-5.0
tags:
  analytic_story:
  - Active Directory Discovery
  asset_type: Endpoint
  confidence: 50
  impact: 30
  message: System user discovery on $dest$ by $user$
  mitre_attack_id:
  - T1033
  observable:
  - name: dest
    type: Endpoint
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - Path
  - Message
  - OpCode
  - ComputerName
  - User
  - EventCode
  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-powershell-xml.log
    source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
    sourcetype: xmlwineventlog