Sigma rule: Winlogon Helper DLL

Rule

Title

Winlogon Helper DLL

Status

test

Level

medium

Author

Timur Zinniatullin, oscd.community

Date

2019-10-21

Modified

2022-07-07

File

rules/windows/powershell/powershell_script/posh_ps_winlogon_helper_dll.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

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. Malicious modifications to these Registry keys may cause Winlogon to
load and execute malicious DLLs and/or executables.

Log source

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*

False positives (as the rule lists them)

• Unknown

Tags

• attack.privilege-escalation
• attack.persistence
• attack.t1547.004

MITRE ATT&CK ids this rule names

• T1547.004

References

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1547.004/T1547.004.md

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_script/posh_ps_winlogon_helper_dll.yml