name: GetCurrent User with PowerShell Script Block
id: 80879283-c30f-44f7-8471-d1381f6d437a
version: 3
date: '2024-05-21'
author: Mauricio Velazco, Splunk
status: production
type: Hunting
description: The following analytic detects the execution of the `GetCurrent` method
  from the WindowsIdentity .NET class using PowerShell Script Block Logging (EventCode=4104).
  This method identifies the current Windows user. The detection leverages PowerShell
  script block logs to identify when this method is called. This activity is significant
  because adversaries and Red Teams may use it to gain situational awareness and perform
  Active Directory discovery on compromised endpoints. If confirmed malicious, this
  could allow attackers to map out user accounts and potentially escalate privileges
  or move laterally within the network.
data_source:
- Powershell Script Block Logging 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