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Description

The following analytic identifies suspicious PowerShell script execution via EventCode 4104, where WMI performs an event query to list running processes or services. This detection leverages PowerShell Script Block Logging to capture and analyze script block text for specific WMI queries. This activity is significant as it is commonly used by malware and APT actors to map security applications or services on a compromised machine. If confirmed malicious, this could allow attackers to identify and potentially disable security defenses, facilitating further compromise and persistence within the environment.

  • Type: Anomaly

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

  • Last Updated: 2024-05-15
  • Author: Teoderick Contreras, Splunk
  • ID: b5cd5526-cce7-11eb-b3bd-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1592 Gather Victim Host Information Reconnaissance
Kill Chain Phase
  • Reconnaissance
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`powershell` EventCode=4104 ScriptBlockText= "*SELECT*" AND (ScriptBlockText="*Win32_Process*" OR ScriptBlockText="*Win32_Service*") 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
| rename Computer as dest 
| rename UserID as user 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `wmi_recon_running_process_or_services_filter`

Macros

The SPL above uses the following Macros:

:information_source: wmi_recon_running_process_or_services_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
  • ScriptBlockText
  • Opcode
  • Computer
  • UserID
  • EventCode

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

Network administrator may used this command for checking purposes

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
20.0 20 100 Suspicious powerShell script execution by $user$ on $dest$ via EventCode 4104, where WMI is performing an event query looking for running processes or running services

:information_source: 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

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

source | version: 4