Detection: GetWmiObject Ds Computer with PowerShell Script Block

Updated Date: 2024-05-29 ID: 29b99201-723c-4118-847a-db2b3d3fb8ea Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the execution of the Get-WmiObject cmdlet with the DS_Computer class parameter via PowerShell Script Block Logging (EventCode=4104). This detection leverages script block text to identify queries targeting domain computers using WMI. Monitoring this activity is crucial as adversaries and Red Teams may use it for Active Directory Discovery and situational awareness. If confirmed malicious, this behavior could allow attackers to map out domain computers, facilitating further attacks such as lateral movement or privilege escalation.

1`powershell` EventCode=4104 (ScriptBlockText=*Get-WmiObject* AND ScriptBlockText="*namespace root\\directory\\ldap*" AND ScriptBlockText="*class ds_computer*") 
2| stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText 
3| `security_content_ctime(firstTime)` 
4| `getwmiobject_ds_computer_with_powershell_script_block_filter`

Data Source

Name Platform Sourcetype Source Supported App
Powershell Script Block Logging 4104 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational' N/A

Macros Used

Name Value
powershell (source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational")
getwmiobject_ds_computer_with_powershell_script_block_filter search *
getwmiobject_ds_computer_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

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1018 Remote System Discovery Discovery
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT3
APT32
APT39
Akira
BRONZE BUTLER
Chimera
Deep Panda
Dragonfly
Earth Lusca
FIN5
FIN6
FIN8
Fox Kitten
GALLIUM
HAFNIUM
HEXANE
Indrik Spider
Ke3chang
Leafminer
Magic Hound
Naikon
Rocke
Sandworm Team
Scattered Spider
Silence
Threat Group-3390
ToddyCat
Turla
Volt Typhoon
Wizard Spider
menuPass

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 Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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 or power users may use this PowerShell commandlet for troubleshooting.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Remote system discovery enumeration on $Computer$ by $UserID$ 15 30 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 3