T1547.004 Winlogon Helper DLL

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. Registry entries in <code>HKLM\Software[\Wow6432Node\]\Microsoft\Windows NT\CurrentVersion\Winlogon\</code> and <code>HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\</code> are used to manage additional helper programs and functionalities that support Winlogon.(Citation: Cylance Reg Persistence Sept 2013)

Malicious modifications to these Registry keys may cause Winlogon to load and execute malicious DLLs and/or executables. Specifically, the following subkeys have been known to be possibly vulnerable to abuse: (Citation: Cylance Reg Persistence Sept 2013)

  • Winlogon\Notify - points to notification package DLLs that handle Winlogon events
  • Winlogon\Userinit - points to userinit.exe, the user initialization program executed when a user logs on
  • Winlogon\Shell - points to explorer.exe, the system shell executed when a user logs on

Adversaries may take advantage of these features to repeatedly execute malicious code and establish persistence.

View in MITRE ATT&CK®

CRI Profile Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
PR.AA-01.02 Physical and logical access Mitigates T1547.004 Winlogon Helper DLL
Comments
This diagnostic statement describes how the organization ensures users are identified and authenticated before accessing systems, applications, and hardware, with logical access controls permitting access only to authorized individuals with legitimate business needs. Logical access controls in relation to systems can refer to the use of MFA, user account management, and other role-based access control mechanisms to enforce policies for authentication and authorization of user accounts.
References
    PR.AA-01.01 Identity and credential management Mitigates T1547.004 Winlogon Helper DLL
    Comments
    This diagnostic statement protects against Winlogon Helper DLL through the use of hardened access control policies, secure defaults, password complexity requirements, multifactor authentication requirements, and removal of terminated accounts.
    References

      VERIS Mappings

      Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
      action.hacking.variety.Use of stolen creds Use of stolen or default authentication credentials (including credential stuffing) related-to T1547.004 Winlogon Helper DLL
      action.hacking.vector.Command shell Remote shell related-to T1547.004 Winlogon Helper DLL
      attribute.integrity.variety.Modify configuration Modified configuration or services related-to T1547.004 Winlogon Helper DLL

      Azure Mappings

      Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
      file_integrity_monitoring Microsoft Defender for Cloud: File Integrity Monitoring technique_scores T1547.004 Winlogon Helper DLL
      Comments
      This control may detect changes to the Windows registry or files that enable Boot or Logon Autostart Execution. This control at worst scans for changes on an hourly basis.
      References