ID | Technique | Tactic |
---|---|---|
T1087 | Account Discovery | Discovery |
T1087.001 | Local Account | Discovery |
Detection: Windows Account Discovery for None Disable User Account
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.
Search
1`powershell` EventCode=4104 ScriptBlockText = "*Get-NetUser*" ScriptBlockText = "*NOT_ACCOUNTDISABLE*" ScriptBlockText = "*-UACFilter*"
2| rename Computer as dest, UserID as user
3| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText dest user
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `windows_account_discovery_for_none_disable_user_account_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Powershell Script Block Logging 4104 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational' |
Macros Used
Name | Value |
---|---|
powershell | (source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational") |
windows_account_discovery_for_none_disable_user_account_filter | search * |
windows_account_discovery_for_none_disable_user_account_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Risk Event | False |
Implementation
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 may leverage PowerView for legitimate purposes, filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Windows Account Discovery for None Disable User Account using PowerView's Get-NetUser on $dest$. | 15 | 30 | 50 |
References
-
https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-347a
-
https://book.hacktricks.xyz/windows-hardening/basic-powershell-for-pentesters/powerview
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
XmlWinEventLog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
XmlWinEventLog |
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
Source: GitHub | Version: 4