Detection: PowerShell Invoke WmiExec Usage

Updated Date: 2024-11-13 ID: 0734bd21-2769-4972-a5f1-78bb1e011224 Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the execution of the Invoke-WMIExec utility within PowerShell Script Block Logging (EventCode 4104). This detection leverages PowerShell script block logs to identify instances where the Invoke-WMIExec command is used. Monitoring this activity is crucial as it indicates potential lateral movement using WMI commands with NTLMv2 pass-the-hash authentication. If confirmed malicious, this activity could allow an attacker to execute commands remotely on target systems, potentially leading to further compromise and lateral spread within the network.

1`powershell` EventCode=4104 ScriptBlockText IN ("*invoke-wmiexec*") 
2| stats count min(_time) as firstTime max(_time) as lastTime by Computer EventCode ScriptBlockText 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `powershell_invoke_wmiexec_usage_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
powershell (source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational")
powershell_invoke_wmiexec_usage_filter search *
powershell_invoke_wmiexec_usage_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
T1047 Windows Management Instrumentation Execution
Installation
DE.CM
CIS 10

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

False positives should be limited as this analytic is designed to detect a specific utility. It is recommended to apply appropriate filters as needed to minimize the number of false positives.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

PowerShell was identified running a Invoke-WmiExec on $Computer$.

Risk Object Risk Object Type Risk Score Threat Objects
Computer system 100 No Threat Objects

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: 4