Query: alert when Detects uncommon "userinit.exe" child processes, which could be a sign of uncommon shells or login scripts used for pers
Matching passage: Sigma rule: Detects uncommon "userinit.exe" child processes, which could be a sign of uncommon shells or login scripts used for pers. Logsource: windows / process_creation. Rule: title: Uncommon Userinit Child Process id: 0a98a10c-685d-4ab0-bddc-b6bdd1d48458 related: - id: 21d856f9-9281-4ded-9377-51a1a6e2a432 type: similar status: test description: Detects uncommon "userinit.exe" child processes, which could be a sign of uncommon shells or login scripts used for persistence. references: - https://cocomelonc.github.io/persistence/2022/12/09/malware-pers-20.html - https://learn.microsoft.com/en-us/windows-server/administration/server-core/server-core-sconfig#powershell-is-the-default-shell-on-server-core author: Tom Ueltschi (@c_APT_ure), Tim Shelton date: 2019-01-12 modified: 2023-11-14 tags: - attack.privilege-escalation - attack.t1037.001 - attack.persistence logsource: category: process_creation product: windows detection: selection: ParentImage|endswith: \userinit.exe filter_main_explorer: Image|endswith: :\WINDOWS\explorer.exe filter_optional_logonscripts: CommandLine|contains: - netlogon.bat - UsrLogon.cmd filter_optional_windows_core: CommandLine: PowerShell.exe filter_optional_proquota: Image|endswith: - :\Windows\System32\proquota.exe - :\Windows\SysWOW64\proquota.exe filter_optional_citrix: Image|endswith: - :\Program Files (x86)\Citrix\HDX\bin\cmstart.exe - :\Program Files (x86)\Citrix\HDX\bin\icast.exe - :\Program Files (x86)\Citrix\System32\icast.exe - :\Program Files\Citrix\HDX\bin\cmstart.exe - :\Program Files\Citrix\HDX\bin\icast.exe - :\Program Files\Citrix\System32\icast.exe filter_optional_image_null: Image: null condition: selection and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - Legitimate logon scripts or custom shells may trigger false positives. Apply additional filters accordingly. level: high
Near-miss passage: Sigma rule: Detects attempts to add, modify, or delete Windows Credential Guard related registry keys or values via command line too. Logsource: windows / process_creation. Rule: title: Windows Credential Guard Registry Tampering Via CommandLine id: c17d47b7-dcd6-4109-87eb-d1817bd4cbc9 related: - id: 73921b9c-cafd-4446-b0c6-fdb0ace42bc0 type: similar - id: d645ef86-2396-48a1-a2b6-b629ca3f57ff type: similar status: experimental description: 'Detects attempts to add, modify, or delete Windows Credential Guard related registry keys or values via command line tools such as Reg.exe or PowerShell. Credential Guard uses virtualization-based security to isolate secrets so that only privileged system software can access them. Adversaries may disable Credential Guard to gain access to sensitive credentials stored in the system, such as NTLM hashes and Kerberos tickets, which can be used for lateral movement and privilege escalation. The rule matches suspicious command lines that target DeviceGuard or LSA registry paths and manipulate keys like EnableVirtualizationBasedSecurity, RequirePlatformSecurityFeatures, or LsaCfgFlags. Such activity may indicate an attempt to disable or tamper with Credential Guard, potentially exposing sensitive credentials for misuse. ' references: - https://woshub.com/disable-credential-guard-windows/ - https://learn.microsoft.com/en-us/windows/client-management/mdm/policy-csp-deviceguard author: Swachchhanda Shrawan Poudel (Nextron Systems) date: 2025-12-26 tags: - attack.defense-impairment - attack.t1685 logsource: category: process_creation product: windows detection: selection_img: - Image|endswith: - \powershell.exe - \pwsh.exe - \reg.exe - OriginalFileName: - PowerShell.EXE - pwsh.dll - reg.exe selection_cli: CommandLine|contains: - 'add ' - 'New-ItemProperty ' - 'Set-ItemProperty ' - 'si ' - 'delete ' - 'del ' - 'Remove-ItemProperty ' - 'rp ' selection_key_base: CommandLine|contains: - \Control\DeviceGuard - \Control\LSA - Software\Policies\Microsoft\Windows\DeviceGuard selection_key_specific: CommandLine|contains: - EnableVirtualizationBasedSecurity - RequirePlatformSecurityFeatures - LsaCfgFlags condition: all of selection_* falsepositives: - Unlikely level: high regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_credential_guard_registry_tampering/info.yml