Remote Process Instantiation via WMI and PowerShell Script Block

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Description

The following analytic detects the execution of the Invoke-WmiMethod commandlet with parameters used to start a process on a remote endpoint via WMI, leveraging PowerShell Script Block Logging (EventCode=4104). This method identifies specific script block text patterns associated with remote process instantiation. This activity is significant as it may indicate lateral movement or remote code execution attempts by adversaries. If confirmed malicious, this could allow attackers to execute arbitrary code on remote systems, potentially leading to further compromise and persistence within the network.

• Type: TTP

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

• Last Updated: 2024-05-14
• 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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