Detection rules › Sigma
Winlogon Helper DLL
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1547.004 Boot or Logon Autostart Execution: Winlogon Helper DLL |
| Privilege Escalation | T1547.004 Boot or Logon Autostart Execution: Winlogon Helper DLL |
Event coverage
| Provider | Event | Title |
|---|---|---|
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body yaml
title: Winlogon Helper DLL
id: 851c506b-6b7c-4ce2-8802-c703009d03c0
status: test
description: |
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.
references:
- https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1547.004/T1547.004.md
author: Timur Zinniatullin, oscd.community
date: 2019-10-21
modified: 2022-07-07
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
Stages and Predicates
Stage 0: condition
all of selection*Stage 1: selection
selection:
ScriptBlockText|contains: 'CurrentVersion\Winlogon'
Stage 2: selection2
selection2:
ScriptBlockText|contains:
- 'Set-ItemProperty'
- 'New-Item'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
ScriptBlockText | match |
|