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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.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2022-03-22
  • Author: Mauricio Velazco, Splunk
  • ID: 80879283-c30f-44f7-8471-d1381f6d437a

Annotations

ATT&CK
ID Technique Tactic
T1033 System Owner/User Discovery Discovery
Kill Chain Phase
  • Reconnaissance
NIST
CIS20
CVE
1
2
3
4
5
`powershell` EventCode=4104 ScriptBlockText = "*[System.Security.Principal.WindowsIdentity]*"  ScriptBlockText = "*GetCurrent()*" 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `getcurrent_user_with_powershell_script_block_filter`

Macros

The SPL above uses the following Macros:

Note that getcurrent_user_with_powershell_script_block_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • Path
  • Message
  • OpCode
  • ComputerName
  • User
  • EventCode

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.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
15.0 30 50 System user discovery on $dest$

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 2