Suspicious Winlogon Helper DLL (via ps_script)

title: Suspicious Winlogon Helper DLL (via ps_script)
id: 9b6b00b2-c877-541c-9af5-97aff1c78044
status: stable
description: This rule detects Winlogon.exe is a Windows component responsible for actions at logon/logoff as well as the secure attention sequence (SAS) triggered by Ctrl-Alt-Delete. Registry entries in HKLM\Software[Wow6432Node]Microsoft\Windows NT\CurrentVersion\Winlogon\ and HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\ are used to manage additional helper programs and functionalities that support Winlogon. Hostile modifications to these Registry keys may cause Winlogon to load and execute hostile DLLs and/or executables.
references:
    - https://attack.mitre.org/techniques/T1547/004/
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1547.004/T1547.004.md
author: Huntrule Team
date: 2026-06-23
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547.004
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains: 'CurrentVersion\Winlogon'
    selection2:
        ScriptBlockText|contains:
            - 'Set-ItemProperty'
            - 'New-Item'
    condition: all of selection*
falsepositives:
    - Unknown
level: medium