Detection rules › Splunk

Windows Account Discovery for None Disable User Account

Status
production
Group by
Guid, Name, Opcode, Path, ScriptBlockId, ScriptBlockText, dest, process_id, signature, signature_id, user_id, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

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.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Windows Account Discovery for None Disable User Account
id: eddbf5ba-b89e-47ca-995e-2d259804e55e
version: 11
creation_date: '2024-01-10'
modification_date: '2026-05-13'
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/
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
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

Stages and Predicates

Stage 1: search

`powershell` EventCode=4104  ScriptBlockText = "*Get-NetUser*" ScriptBlockText = "*NOT_ACCOUNTDISABLE*" ScriptBlockText = "*-UACFilter*"

Stage 2: fillnull

| fillnull

Stage 3: stats

| 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

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `windows_account_discovery_for_none_disable_user_account_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 4104 corpus 268 (splunk 268)
ScriptBlockTexteq
  • "*-UACFilter*"
  • "*Get-NetUser*" corpus 4 (splunk 4)
  • "*NOT_ACCOUNTDISABLE*"