Get WMIObject Group Discovery with Script Block Logging

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Description

The following analytic detects the execution of the Get-WMIObject Win32_Group command using PowerShell Script Block Logging (EventCode=4104). This method captures the full command sent to PowerShell, allowing for detailed analysis. Identifying group information on an endpoint is not inherently malicious but can be suspicious based on context such as time, endpoint, and user. This activity is significant as it may indicate reconnaissance efforts by an attacker. If confirmed malicious, it could lead to further enumeration and potential lateral movement within the network.

• Type: Hunting

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2024-05-23
• Author: Michael Haag, Splunk
• ID: 69df7f7c-155d-11ec-a055-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1069	Permission Groups Discovery	Discovery

T1069.001

Local Groups

Discovery

Kill Chain Phase

• Exploitation

NIST

• DE.AE

CIS20

• CIS 10

CVE

Search

`powershell` EventCode=4104 ScriptBlockText = "*Get-WMIObject*" AND ScriptBlockText = "*Win32_Group*" 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
| rename Computer as dest, UserID as user 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `get_wmiobject_group_discovery_with_script_block_logging_filter`

Macros

The SPL above uses the following Macros:

• powershell
• security_content_ctime

get_wmiobject_group_discovery_with_script_block_logging_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

• _time
• EventCode
• Message
• ComputerName
• User

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://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.

Known False Positives

False positives may be present. Tune as needed.

Associated Analytic Story

• Active Directory Discovery

RBA

Risk Score	Impact	Confidence	Message
15.0	30	50	System group discovery enumeration on $dest$ by $user$.

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://www.splunk.com/en_us/blog/security/powershell-detections-threat-research-release-august-2021.html
• https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1069.001/T1069.001.md
• https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
• https://blog.palantir.com/tampering-with-windows-event-tracing-background-offense-and-defense-4be7ac62ac63
• https://static1.squarespace.com/static/552092d5e4b0661088167e5c/t/59c1814829f18782e24f1fe2/1505853768977/Windows+PowerShell+Logging+Cheat+Sheet+ver+Sept+2017+v2.1.pdf
• https://www.crowdstrike.com/blog/investigating-powershell-command-and-script-logging/

Test Dataset

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

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