Windows Account Discovery for None Disable User Account

 Original Source: [splunk source]
Name:Windows Account Discovery for None Disable User Account
id:eddbf5ba-b89e-47ca-995e-2d259804e55e
version:11
date:None
author:Teoderick Contreras, Splunk
status:production
type:Hunting
Description:The following analytic detects the execution of the PowerView PowerShell cmdlet Get-NetUser with the UACFilter parameter set to NOT_ACCOUNTDISABLE, indicating an attempt to enumerate Active Directory user accounts that are not disabled. This detection leverages PowerShell Script Block Logging (EventCode 4104) to identify the specific script block text. Monitoring this activity is significant as it may indicate reconnaissance efforts by an attacker to identify active user accounts for further exploitation. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, or lateral movement within the network.
Data_source:
  • -Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 ScriptBlockText = "*Get-NetUser*" ScriptBlockText = "*NOT_ACCOUNTDISABLE*" ScriptBlockText = "*-UACFilter*"

| fillnull

| stats count min(_time) as firstTime max(_time) as lastTime
BY dest signature signature_id
user_id vendor_product EventID
Guid Opcode Name
Path ProcessID ScriptBlockId
ScriptBlockText

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| `windows_account_discovery_for_none_disable_user_account_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://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.=
known_false_positives:Administrators may leverage PowerView for legitimate purposes, filter as needed.
References:
  -https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-347a
  -https://powersploit.readthedocs.io/en/stable/Recon/README/
  -https://book.hacktricks.xyz/windows-hardening/basic-powershell-for-pentesters/powerview
  -https://atomicredteam.io/discovery/T1087.001/
drilldown_searches:
  :
analytic_story:['CISA AA23-347A']

asset_type:Endpoint

mitre_attack_id:['T1087.001']

product:['Splunk Enterprise', 'Splunk Enterprise Security', 'Splunk Cloud']

category:endpoint

security_domain:endpoint

tags:

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1087/powerview_get_netuser_preauthnotrequire/get-netuser-not-require-pwh.log
  source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
  sourcetype: XmlWinEventLog
 test_type:'unit'
manual_test:None

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CISA AA23-347A