Detection: Windows PowerShell Disabled Kerberos Pre-Authentication Discovery With PowerView

Description

The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the Get-DomainUser commandlet with specific parameters. Get-DomainUser is part of PowerView, a PowerShell tool used to perform enumeration on Windows Active Directory networks. As the name suggests, Get-DomainUser is used to identify domain users and combining it with -PreauthNotRequired allows adversaries to discover domain accounts with Kerberos Pre Authentication disabled. Red Teams and adversaries alike use may leverage PowerView to enumerate these accounts and attempt to crack their passwords offline.

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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

Administrators or power users may use PowerView for troubleshooting

Associated Analytic Story

• Active Directory Kerberos Attacks

Risk Based Analytics (RBA)

References

• https://attack.mitre.org/techniques/T1558/004/

• https://m0chan.github.io/2019/07/31/How-To-Attack-Kerberos-101.html

• https://stealthbits.com/blog/cracking-active-directory-passwords-with-as-rep-roasting/

Version: 4