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splunk-security_content/detections/endpoint/getcurrent_user_with_powershell_script_block.yml
2023-09-22 15:47:54 -07:00

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YAML

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