userinit.exe

File Path: C:\WINDOWS\SysWOW64\userinit.exe
Description: Userinit Logon Application

Hashes

Type	Hash
MD5	`A83702100F695127901004594BAF8E84`
SHA1	`915600176F304363F04880110B978CB94FCC9F6C`
SHA256	`AF1519BEC6ADBE3815D082002803FD0570058C324A51F5BE15194A058FF03275`
SHA384	`4EC00E7A1073F8F096A4D2D05DF107B3F63DA23B3B6A993E15BE2F514F49174C73BF8E82F32A305675F58D94872A3B29`
SHA512	`52F330626CD2755035DAAB0A7B4EA7E48DC8DB14CAE27326B043618A1C9A2E592BD51E7D983422BA0E734D59FF07C95A9DEFBB933584CBA4ECCC70395C39EA33`
SSDEEP	`384:Uwo38oAephzq+dtPzq0zUQm9J7uEQN2VMQn7RgWbymWhBGy:Uj38k7zq+bLjBm9d5QN23nS5BT`

Signature

Status: Signature verified.
Serial: 330000023241FB59996DCC4DFF000000000232
Thumbprint: FF82BC38E1DA5E596DF374C53E3617F7EDA36B06
Issuer: CN=Microsoft Windows Production PCA 2011, O=Microsoft Corporation, L=Redmond, S=Washington, C=US
Subject: CN=Microsoft Windows, O=Microsoft Corporation, L=Redmond, S=Washington, C=US

File Metadata

Original Filename: USERINIT.EXE
Product Name: Microsoft Windows Operating System
Company Name: Microsoft Corporation
File Version: 10.0.18362.1 (WinBuild.160101.0800)
Product Version: 10.0.18362.1
Language: English (United States)

Possible Misuse

The following table contains possible examples of userinit.exe being misused. While userinit.exe is not inherently malicious, its legitimate functionality can be abused for malicious purposes.

Source	Source File	Example	License
sigma	sysmon_suspicious_remote_thread.yml	`- '\userinit.exe'`	DRL 1.0
sigma	proc_creation_win_logon_scripts_userinitmprlogonscript_proc.yml	`ParentImage\\|endswith: '\userinit.exe'`	DRL 1.0
sigma	proc_creation_win_susp_direct_asep_reg_keys_modification.yml	`- '\software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit'`	DRL 1.0
sigma	proc_creation_win_susp_userinit_child.yml	`title: Suspicious Userinit Child Process`	DRL 1.0
sigma	proc_creation_win_susp_userinit_child.yml	`description: Detects a suspicious child process of userinit`	DRL 1.0
sigma	proc_creation_win_susp_userinit_child.yml	`ParentImage\\|endswith: '\userinit.exe'`	DRL 1.0
sigma	registry_event_asep_reg_keys_modification.yml	`- '\Winlogon\Userinit'`	DRL 1.0
sigma	registry_event_asep_reg_keys_modification_currentversion_nt.yml	`- '\Winlogon\Userinit'`	DRL 1.0
malware-ioc	misp_invisimole.json	"description": "Adding an entry to the \"run keys\" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. (Citation: Microsoft Run Key) These programs will be executed under the context of the user and will have the account's associated permissions level.\n\nThe following run keys are created by default on Windows systems:\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Run</code>\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\RunOnce</code>\n* <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Run</code>\n* <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\RunOnce</code>\n\nThe <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\RunOnceEx</code> is also available but is not created by default on Windows Vista and newer. Registry run key entries can reference programs directly or list them as a dependency. (Citation: Microsoft RunOnceEx APR 2018) For example, it is possible to load a DLL at logon using a \"Depend\" key with RunOnceEx: <code>reg add HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\RunOnceEx\\0001\\Depend /v 1 /d \"C:\\temp\\evil[.]dll\"</code> (Citation: Oddvar Moe RunOnceEx Mar 2018)\n\nThe following Registry keys can be used to set startup folder items for persistence:\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\User Shell Folders</code>\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders</code>\n* <code>HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders</code>\n* <code>HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\User Shell Folders</code>\n\nThe following Registry keys can control automatic startup of services during boot:\n* <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\RunServicesOnce</code>\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\RunServicesOnce</code>\n* <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\RunServices</code>\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\RunServices</code>\n\nUsing policy settings to specify startup programs creates corresponding values in either of two Registry keys:\n* <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer\\Run</code>\n* <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer\\Run</code>\n\nThe Winlogon key controls actions that occur when a user logs on to a computer running Windows 7. Most of these actions are under the control of the operating system, but you can also add custom actions here. The <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon\\Userinit</code> and <code>HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon\\Shell</code> subkeys can automatically launch programs.\n\nPrograms listed in the load value of the registry key <code>HKEY_CURRENT_USER\\Software\\Microsoft\\Windows NT\\CurrentVersion\\Windows</code> run when any user logs on.\n\nBy default, the multistring BootExecute value of the registry key <code>HKEY_LOCAL_MACHINE\\System\\CurrentControlSet\\Control\\Session Manager</code> is set to autocheck autochk *. This value causes Windows, at startup, to check the file-system integrity of the hard disks if the system has been shut down abnormally. Adversaries can add other programs or processes to this registry value which will automatically launch at boot.\n\n\nAdversaries can use these configuration locations to execute malware, such as remote access tools, to maintain persistence through system reboots. Adversaries may also use [Masquerading](https://attack.mitre.org/techniques/T1036) to make the Registry entries look as if they are associated with legitimate programs.",	© ESET 2014-2018
malware-ioc	part3.adoc	`userinit.exe`	© ESET 2014-2018
atomic-red-team	index.md	- Atomic Test #2: Winlogon Userinit Key Persistence - PowerShell [windows]	MIT License. © 2018 Red Canary
atomic-red-team	windows-index.md	- Atomic Test #2: Winlogon Userinit Key Persistence - PowerShell [windows]	MIT License. © 2018 Red Canary
atomic-red-team	T1012.md	reg query “HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit”	MIT License. © 2018 Red Canary
atomic-red-team	T1547.001.md	The Winlogon key controls actions that occur when a user logs on to a computer running Windows 7. Most of these actions are under the control of the operating system, but you can also add custom actions here. The `HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit` and `HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell` subkeys can automatically launch programs.	MIT License. © 2018 Red Canary
atomic-red-team	T1547.004.md	* Winlogon\Userinit - points to userinit.exe, the user initialization program executed when a user logs on	MIT License. © 2018 Red Canary
atomic-red-team	T1547.004.md	- Atomic Test #2 - Winlogon Userinit Key Persistence - PowerShell	MIT License. © 2018 Red Canary
atomic-red-team	T1547.004.md	## Atomic Test #2 - Winlogon Userinit Key Persistence - PowerShell	MIT License. © 2018 Red Canary
atomic-red-team	T1547.004.md	PowerShell code to set Winlogon userinit key to execute a binary at logon along with userinit.exe.	MIT License. © 2018 Red Canary
atomic-red-team	T1547.004.md	Set-ItemProperty “HKCU:\Software\Microsoft\Windows NT\CurrentVersion\Winlogon" “Userinit” “Userinit.exe, #{binary_to_execute}” -Force	MIT License. © 2018 Red Canary
atomic-red-team	T1547.004.md	Remove-ItemProperty -Path “HKCU:\Software\Microsoft\Windows NT\CurrentVersion\Winlogon" -Name “Userinit” -Force -ErrorAction Ignore	MIT License. © 2018 Red Canary