GitHub Repo

Detection: Windows Enable PowerShell Web Access

Updated Date: 2026-05-13 ID: 175bb2de-6227-416b-9678-9b61999cd21f Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the enabling of PowerShell Web Access via PowerShell commands. It leverages PowerShell script block logging (EventCode 4104) to identify the execution of the Install-WindowsFeature cmdlet with the WindowsPowerShellWebAccess parameter. This activity is significant because enabling PowerShell Web Access can facilitate remote execution of PowerShell commands, potentially allowing an attacker to gain unauthorized access to systems and networks.

 1`powershell` EventCode=4104 ScriptBlockText IN ("*Install-WindowsFeature*WindowsPowerShellWebAccess*","*Install-PswaWebApplication*","*Add-PswaAuthorizationRule*UserName *ComputerName *")
 2  
 3| fillnull
 4  
 5| stats count min(_time) as firstTime max(_time) as lastTime
 6    BY dest signature signature_id
 7       user_id vendor_product EventID
 8       Guid Opcode Name
 9       Path ProcessID ScriptBlockId
10       ScriptBlockText
11  
12| `security_content_ctime(firstTime)`
13  
14| `security_content_ctime(lastTime)`
15  
16| `windows_enable_powershell_web_access_filter`

Data Source

Name Platform Sourcetype Source
Powershell Script Block Logging 4104 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_enable_powershell_web_access_filter search *
windows_enable_powershell_web_access_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1059.001 PowerShell Execution
Installation
DE.CM
CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Finding (Notable) Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Intermediate Finding (Risk Event) No
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.

Known False Positives

It is possible that legitimate scripts or network administrators may enable PowerShell Web Access. Monitor and escalate as needed.

Associated Analytic Story

Finding

Title Entity Field Entity Type Risk Score
PowerShell Web Access has been enabled on $dest$. dest system 50

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-PowerShell/Operational XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-PowerShell/Operational XmlWinEventLog

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: GitHub | Version: 11