Detection: Windows PowerShell Disabled Kerberos Pre-Authentication Discovery Get-ADUser
Description
The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the Get-ADUser
commandlet with specific parameters. Get-ADUser
is part of the Active Directory PowerShell module used to manage Windows Active Directory networks. As the name suggests, Get-ADUser
is used to query for domain users. With the appropiate parameters, Get-ADUser allows adversaries to discover domain accounts with Kerberos Pre Authentication disabled.\ Red Teams and adversaries alike use may abuse Get-ADUSer to enumerate these accounts and attempt to crack their passwords offline.
Annotations
No annotations available.
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 search for accounts with Kerberos Pre Authentication disabled for legitimate purposes.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Disabled Kerberos Pre-Authentication Discovery With Get-ADUser from $dest_device_id$ | 54 | 60 | 90 |
References
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https://m0chan.github.io/2019/07/31/How-To-Attack-Kerberos-101.html
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https://stealthbits.com/blog/cracking-active-directory-passwords-with-as-rep-roasting/
Version: 4