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splunk-security_content/detections/endpoint/getcurrent_user_with_powershell_script_block.yml
2021-09-14 11:54:58 -04:00

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YAML

name: GetCurrent User with PowerShell Script Block
id: 80879283-c30f-44f7-8471-d1381f6d437a
version: 1
date: '2021-09-13'
author: Mauricio Velazco, Splunk
type: Hunting
datamodel:
- Endpoint
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.
search: '`powershell` EventCode=4104 (Message = "*[System.Security.Principal.WindowsIdentity]*"
AND Message = "*GetCurrent()*") | stats count min(_time) as firstTime max(_time)
as lastTime by EventCode Message ComputerName User | `security_content_ctime(firstTime)`
| `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-5.0
tags:
analytic_story:
- Active Directory Discovery
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1033/AD_discovery/windows-powershell.log
kill_chain_phases:
- Reconnaissance
mitre_attack_id:
- T1033
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- Path
- Message
- OpCode
- ComputerName
- User
- EventCode
security_domain: endpoint
impact: 30
confidence: 50
risk_score: 15
context:
- Source:Endpoint
- Stage:Discovery
- Stage:Recon
message: System user discovery on $dest$
observable:
- name: dest
type: Endpoint
role:
- Victim
automated_detection_testing: passed