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Description

The following analytic leverages Event ID 4104 to identify the execution of the PowerView powershell commandlets Get-NetUser. In the context of PowerView's Get-NetUser cmdlet as a filter or parameter to query Active Directory user account's "samccountname". This hunting query is a good pivot to look for suspicious process or malware that gather user account information in a host or within network system.

  • Type: Anomaly

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

  • Last Updated: 2023-12-15
  • Author: Teoderick Contreras, Splunk
  • ID: 69934363-e1dd-4c49-8651-9d7663dd4d2f

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1087 Account Discovery Discovery
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`powershell` EventCode=4104  ScriptBlockText = "*Get-NetUser*" ScriptBlockText IN ("*samaccountname*", "*pwdlastset*") 
| rename Computer as dest, UserID as user 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText dest user 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_account_discovery_for_sam_account_name_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_account_discovery_for_sam_account_name_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
  • ScriptBlockText
  • dest
  • EventCode
  • user

How To Implement

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 may leverage PowerView for legitimate purposes, filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
15.0 30 50 Windows Account Discovery for Sam Account Name 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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