Detection: GetDomainController with PowerShell Script Block

Description

The following analytic detects the execution of the Get-DomainController commandlet using PowerShell Script Block Logging (EventCode=4104). This commandlet is part of PowerView, a tool often used for domain enumeration. The detection leverages script block text to identify this specific activity. Monitoring this behavior is crucial as it may indicate an adversary or Red Team performing reconnaissance to map out domain controllers. If confirmed malicious, this activity could lead to further domain enumeration, potentially exposing sensitive information and aiding in lateral movement within the network.

 1`powershell` EventCode=4104 (ScriptBlockText = "*Get-DomainController*")
 2  
 3| fillnull
 4  
 5| stats count min(_time) as firstTime max(_time) as lastTime
 6    BY dest signature signature_id
 7       user_id vendor_product EventID
 8       Guid Opcode Name
 9       Path ProcessID ScriptBlockId
10       ScriptBlockText
11  
12| `security_content_ctime(firstTime)`
13  
14| `getdomaincontroller_with_powershell_script_block_filter`

Data Source

Name Platform Sourcetype Source
Powershell Script Block Logging 4104 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
getdomaincontroller_with_powershell_script_block_filter search *
getdomaincontroller_with_powershell_script_block_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 Finding (Notable) Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Intermediate Finding (Risk Event) No
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

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 or power users may use this PowerShell commandlet for troubleshooting.

Associated Analytic Story

Finding

Title Entity Field Entity Type Risk Score
Remote system discovery with PowerView on $dest$ by $user_id$ dest system 50

References

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: 12