Winlogon Notify Key Logon Persistence

Status: test
Severity: high
Log source: category registry_set, product windows
Author: frack113
Source: github.com/SigmaHQ/sigma

Adversaries may abuse features of Winlogon to execute DLLs and/or executables when a user logs in. 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.

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

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 13: RegistryEvent (Value Set)

Rule body

title: Winlogon Notify Key Logon Persistence
id: bbf59793-6efb-4fa1-95ca-a7d288e52c88
status: test
description: |
    Adversaries may abuse features of Winlogon to execute DLLs and/or executables when a user logs in.
    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.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1547.004/T1547.004.md#atomic-test-3---winlogon-notify-key-logon-persistence---powershell
author: frack113
date: 2021-12-30
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547.004
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\logon'
        Details|endswith: '.dll'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    TargetObject|endswith: '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\logon'
    Details|endswith: '.dll'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Details`	ends_with	`.dll` corpus 9 (sigma 4, elastic 4, splunk 1)	`field:"Details" kind:ends_with value:".dll"`
`TargetObject`	ends_with	`\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\logon`	`field:"TargetObject" kind:ends_with value:"\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\logon"`