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Description

This analytic identifies the use of Get-CimInstance cmdlet with the -ComputerName parameter, which indicates that the cmdlet is being used to retrieve information from a remote computer. This can be useful for detecting instances of remote access, such as when an attacker uses PowerShell to connect to a remote system and gather information. By monitoring for this cmdlet with the -ComputerName parameter, security analysts can identify potential malicious activity on remote systems and take appropriate action to mitigate any threats.

  • Type: Anomaly

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

  • Last Updated: 2023-03-27
  • Author: Michael Haag, Splunk
  • ID: d8c972eb-ed84-431a-8869-ca4bd83257d1

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1059.001 PowerShell Execution
Kill Chain Phase
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`powershell` EventCode=4104 ScriptBlockText="*get-ciminstance*" AND ScriptBlockText="*computername*"  
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_powershell_get_ciminstance_remote_computer_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_powershell_get_ciminstance_remote_computer_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
  • Computer
  • 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

This is meant to be a low risk RBA anomaly analytic or to be used for hunting. Enable this with a low risk score and let it generate risk in the risk index.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
15.0 30 50 A PowerShell Cmdlet Get-CIMInstnace was ran on $Computer$, attempting to connect to a remote host.

: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

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