Recon Using WMI Class

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Description

The following analytic identifies suspicious PowerShell via EventCode 4104, where WMI is performing an event query looking for running processes or running services. This technique is commonly found where the adversary will identify services and system information on the compromised machine. During triage, review parallel processes within the same timeframe. Review the full script block to identify other related artifacts.

• Type: Anomaly

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

• Last Updated: 2023-11-07
• 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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