Remote Process Instantiation via WMI and PowerShell Script Block

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Description

The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the Invoke-WmiMethod commandlet with arguments utilized to start a process on a remote endpoint by abusing WMI. Red Teams and adversaries alike may abuse WMI and this commandlet for lateral movement and remote code execution.

• Type: TTP

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

• Last Updated: 2022-11-15
• Author: Mauricio Velazco, Splunk
• ID: 2a048c14-4634-11ec-a618-3e22fbd008af

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1047	Windows Management Instrumentation	Execution

Kill Chain Phase

• Installation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

`powershell` EventCode=4104 ScriptBlockText="*Invoke-WmiMethod*" AND (ScriptBlockText="*-CN*" OR ScriptBlockText="*-ComputerName*") AND ScriptBlockText="*-Class Win32_Process*" AND ScriptBlockText="*-Name create*" 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID
|  `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `remote_process_instantiation_via_wmi_and_powershell_script_block_filter`

Macros

The SPL above uses the following Macros:

• powershell
• security_content_ctime

remote_process_instantiation_via_wmi_and_powershell_script_block_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
• Computer
• UserID

How To Implement

To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup instructions can be found https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.

Known False Positives

Administrators may leverage WWMI and powershell.exe to start a process on remote systems, but this activity is usually limited to a small set of hosts or users.

Associated Analytic Story

• Active Directory Lateral Movement

RBA

Risk Score	Impact	Confidence	Message
63.0	90	70	A process was started on a remote endpoint from $Computer$ by abusing WMI using PowerShell.exe

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://attack.mitre.org/techniques/T1047/
• https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.management/invoke-wmimethod?view=powershell-5.1

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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