Detection: Detect Mimikatz With PowerShell Script Block Logging

Description

The following analytic detects the execution of Mimikatz commands via PowerShell by leveraging PowerShell Script Block Logging (EventCode=4104). This method captures and logs the full command sent to PowerShell, allowing for the identification of suspicious activities such as Pass the Ticket, Pass the Hash, and credential dumping. This activity is significant as Mimikatz is a well-known tool used for credential theft and lateral movement. If confirmed malicious, this could lead to unauthorized access, privilege escalation, and potential compromise of sensitive information within the environment.

Search

1`powershell` EventCode=4104 ScriptBlockText IN (*mimikatz*, *-dumpcr*, *sekurlsa::pth*, *kerberos::ptt*, *kerberos::golden*) 
2| stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `detect_mimikatz_with_powershell_script_block_logging_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Powershell Script Block Logging 4104	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational'	N/A

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

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

False positives should be limited as the commands being identifies are quite specific to EventCode 4104 and Mimikatz. Filter as needed.

Associated Analytic Story

• CISA AA22-264A

• CISA AA22-320A

• CISA AA23-347A

• Data Destruction

• Hermetic Wiper

• Malicious PowerShell

• Sandworm Tools

Risk Based Analytics (RBA)

References

• 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

Detection Testing

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: GitHub | Version: 3