Recon Using WMI Class

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Description

The following analytic detects suspicious PowerShell activity via EventCode 4104, where WMI performs event queries to gather information on running processes or services. This detection leverages PowerShell Script Block Logging to identify specific WMI queries targeting system information classes like Win32_Bios and Win32_OperatingSystem. This activity is significant as it often indicates reconnaissance efforts by an adversary to profile the compromised machine. If confirmed malicious, the attacker could gain detailed system information, aiding in further exploitation or lateral movement within the network.

• Type: Anomaly

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

• Last Updated: 2024-05-18
• Author: Teoderick Contreras, Splunk
• ID: 018c1972-ca07-11eb-9473-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1592	Gather Victim Host Information	Reconnaissance

T1059.001

PowerShell

Execution

Kill Chain Phase

• Reconnaissance
• Installation

NIST

• DE.AE

CIS20

• CIS 10

CVE

Search

`powershell` EventCode=4104 (ScriptBlockText= "*SELECT*" OR ScriptBlockText= "*Get-WmiObject*") AND (ScriptBlockText= "*Win32_Bios*" OR ScriptBlockText= "*Win32_OperatingSystem*" OR ScriptBlockText= "*Win32_Processor*" OR ScriptBlockText= "*Win32_ComputerSystem*" OR ScriptBlockText= "*Win32_PnPEntity*" OR ScriptBlockText= "*Win32_ShadowCopy*" OR ScriptBlockText= "*Win32_DiskDrive*" OR ScriptBlockText= "*Win32_PhysicalMemory*") 
| 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)` 
| `recon_using_wmi_class_filter`

Macros

The SPL above uses the following Macros:

• powershell
• security_content_ctime

recon_using_wmi_class_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
• ScriptBlockText
• 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 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

• AsyncRAT
• Qakbot
• Industroyer2
• Hermetic Wiper
• LockBit Ransomware
• Malicious PowerShell
• Data Destruction

RBA

Risk Score	Impact	Confidence	Message
60.0	75	80	A suspicious powershell script contains host recon commands detected on host $dest$

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://news.sophos.com/en-us/2020/05/12/maze-ransomware-1-year-counting/
• 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/
• https://www.splunk.com/en_us/blog/security/hunting-for-malicious-powershell-using-script-block-logging.html
• https://www.welivesecurity.com/2022/04/12/industroyer2-industroyer-reloaded/
• https://blogs.vmware.com/security/2022/10/lockbit-3-0-also-known-as-lockbit-black.html

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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