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Description

The following analytic detects the execution of the PowerView PowerShell cmdlet Get-NetComputer, which is used to query Active Directory for user account details such as "samaccountname," "accountexpires," "lastlogon," and more. It leverages Event ID 4104 from PowerShell Script Block Logging to identify this activity. This behavior is significant as it may indicate an attempt to gather user account information, which is often a precursor to further malicious actions. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, or lateral movement within the network.

  • Type: Anomaly

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

  • Last Updated: 2024-05-30
  • Author: Teoderick Contreras, Splunk
  • ID: a7fbbc4e-4571-424a-b627-6968e1c939e4

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1087 Account Discovery Discovery
T1087.002 Domain Account Discovery
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`powershell` EventCode=4104  ScriptBlockText = "*Get-NetComputer*" ScriptBlockText IN ("*samaccountname*", "*accountexpires*", "*lastlogon*", "*lastlogoff*", "*pwdlastset*", "*logoncount*") 
| 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_domain_account_discovery_via_get_netcomputer_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_domain_account_discovery_via_get-netcomputer_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 Domain Account Discovery Via Get-NetComputer in $dest$.

: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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