splunk-security_content/docs/_posts/2022-03-22-getlocaluser_with_powershell_script_block.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
GetLocalUser with PowerShell Script Block	Account Discovery , Local Account , PowerShell	Endpoint	2022-03-22	true		Account Discovery Local Account PowerShell Discovery Discovery Execution Splunk Enterprise Splunk Enterprise Security Splunk Cloud

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Description

The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the Get-LocalUser commandlet. The Get-LocalUser commandlet is used to return a list of all local users. Red Teams and adversaries may leverage this commandlet to enumerate users 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: 2e891cbe-0426-11ec-9c9c-acde48001122

Annotations

ATT&CK

ID	Technique	Tactic
T1087	Account Discovery	Discovery

| T1087.001 | Local Account | Discovery |

| T1059.001 | PowerShell | Execution |

Kill Chain Phase

• Reconnaissance

NIST

CIS20

CVE

Search

`powershell` EventCode=4104 (ScriptBlockText = "*Get-LocalUser*") 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `getlocaluser_with_powershell_script_block_filter`

Macros

The SPL above uses the following Macros:

• powershell
• security_content_ctime

ℹ️ getlocaluser_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
• EventCode
• ScriptBlockText
• Computer
• UserID

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

• Active Directory Discovery
• Malicious PowerShell

RBA

Risk Score	Impact	Confidence	Message
15.0	30	50	Local user discovery enumeration using PowerShell on Computer by user

ℹ️ The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://attack.mitre.org/techniques/T1087/001/
• https://www.splunk.com/en_us/blog/security/hunting-for-malicious-powershell-using-script-block-logging.html

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1087.001/AD_discovery/windows-powershell-xml.log

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