Windows Account Discovery for None Disable User Account
Description
The following analytic utilizes PowerShell Script Block Logging to identify the execution of the PowerView PowerShell commandlet Get-NetUser. In the context of PowerView's Get-NetUser cmdlet as a filter or parameter to query Active Directory user accounts that are not disabled. The full script block text based on the CISA-23-347A advisory is "Get-NetUser -UACFilter NOT_ACCOUNTDISABLE". Utilize this query to identify potential suspicious activity of user account enumeration.
- Type: Hunting
-
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2023-12-15
- Author: Teoderick Contreras, Splunk
- ID: eddbf5ba-b89e-47ca-995e-2d259804e55e
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.AE
CIS20
- CIS 10
CVE
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`powershell` EventCode=4104 ScriptBlockText = "*Get-NetUser*" ScriptBlockText = "*NOT_ACCOUNTDISABLE*" ScriptBlockText = "*-UACFilter*"
| 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_none_disable_user_account_filter`
Macros
The SPL above uses the following Macros:
windows_account_discovery_for_none_disable_user_account_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 None Disable User Account using PowerView's Get-NetUser on $dest$. |
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
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-347a
- https://powersploit.readthedocs.io/en/stable/Recon/README/
- https://book.hacktricks.xyz/windows-hardening/basic-powershell-for-pentesters/powerview
- https://atomicredteam.io/discovery/T1087.001/
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
source | version: 2