LoFP / false positives may be present based on third-party applications or administrators using cim. it is recommended to apply appropriate filters as needed to minimize the number of false positives.

Techniques

• T1047

Sample rules

PowerShell Invoke CIMMethod CIMSession

• source: splunk
• technicques:
  • T1047

Description

This analytic identifies the use of the New-CIMSession cmdlet being created along with the Invoke-CIMMethod cmdlet being used within PowerShell. This particular behavior is similar to the usage of the Invoke-WMIMethod cmdlet, which is known for executing WMI commands on targets using NTLMv2 pass-the-hash authentication. The New-CIMSession cmdlet allows users to create a new CIM session object for a specified computer system, which can then be used to execute CIM operations remotely. Similarly, the Invoke-CIMMethod cmdlet is used to invoke a specified method on one or more CIM objects. Therefore, the combination of New-CIMSession and Invoke-CIMMethod cmdlets in PowerShell can potentially indicate malicious behavior, and this analytic can help detect such activity.

Detection logic

`powershell` EventCode=4104 ScriptBlockText IN ("*invoke-CIMMethod*", "*New-CimSession*") 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer EventCode ScriptBlockText 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `powershell_invoke_cimmethod_cimsession_filter`