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Description

The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the Get-DomainUser or Get-NetUSer commandlets with specific parameters. These commandlets are part of PowerView, a PowerShell tool used to perform enumeration and discovery on Windows Active Directory networks. As the names suggest, these commandlets are used to identify domain users in a network and combining them with the -SPN parameter allows adversaries to discover domain accounts associated with a Service Principal Name (SPN). Red Teams and adversaries alike may leverage PowerView and these commandlets to identify accounts that can be attacked with the Kerberoasting technique.

  • Type: TTP

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

  • Last Updated: 2022-06-22
  • Author: Gowthamaraj Rajendran, Splunk
  • ID: a7093c28-796c-4ebb-9997-e2c18b870837

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1558 Steal or Forge Kerberos Tickets Credential Access
T1558.003 Kerberoasting Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`powershell` EventCode=4104 (ScriptBlockText =*Get-NetUser* OR ScriptBlockText=*Get-DomainUser*) ScriptBlockText= *-SPN* 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
| rename Computer as dest 
| rename UserID as user 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`
| `windows_powerview_spn_discovery_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_powerview_spn_discovery_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
  • EventCode
  • Computer
  • ScriptBlockText

How To Implement

The following analytic requires PowerShell operational logs to be imported. Modify the powershell macro as needed to match the sourcetype or add index. This analytic is specific to 4104, or PowerShell Script Block Logging.

Known False Positives

False positive may include Administrators using PowerView for troubleshooting and management.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
27.0 30 90 PowerView commandlets used for SPN discovery executed on $dest$

: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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