Files With System Process Name In Unsuspected Locations

 Original Source: [Sigma source]
Title: Files With System Process Name In Unsuspected Locations
Status: test
Description:Detects the creation of an executable with a system process name in folders other than the system ones (System32, SysWOW64, etc.). It is highly recommended to perform an initial baseline before using this rule in production.
References:
  -Internal Research
Author: Sander Wiebing, Tim Shelton, Nasreddine Bencherchali (Nextron Systems)
Date: 2020-05-26
modified:2026-07-28
Tags:
  • -'attack.stealth'
  • -'attack.t1036.005'
Logsource:
  • category: file_event
  • product: windows
Detection:
  selection:
    TargetFilename|endswith:
      -'\AtBroker.exe'
      -'\audiodg.exe'
      -'\backgroundTaskHost.exe'
      -'\bcdedit.exe'
      -'\bitsadmin.exe'
      -'\cmdl32.exe'
      -'\cmstp.exe'
      -'\conhost.exe'
      -'\csrss.exe'
      -'\dasHost.exe'
      -'\dfrgui.exe'
      -'\dllhost.exe'
      -'\dwm.exe'
      -'\eventcreate.exe'
      -'\eventvwr.exe'
      -'\explorer.exe'
      -'\extrac32.exe'
      -'\fontdrvhost.exe'
      -'\fsquirt.exe'
      -'\ipconfig.exe'
      -'\iscsicli.exe'
      -'\iscsicpl.exe'
      -'\logman.exe'
      -'\LogonUI.exe'
      -'\LsaIso.exe'
      -'\lsass.exe'
      -'\lsm.exe'
      -'\msiexec.exe'
      -'\msinfo32.exe'
      -'\mstsc.exe'
      -'\nbtstat.exe'
      -'\odbcconf.exe'
      -'\powershell.exe'
      -'\pwsh.exe'
      -'\regini.exe'
      -'\regsvr32.exe'
      -'\rundll32.exe'
      -'\RuntimeBroker.exe'
      -'\schtasks.exe'
      -'\SearchFilterHost.exe'
      -'\SearchIndexer.exe'
      -'\SearchProtocolHost.exe'
      -'\SecurityHealthService.exe'
      -'\SecurityHealthSystray.exe'
      -'\services.exe'
      -'\ShellAppRuntime.exe'
      -'\sihost.exe'
      -'\smartscreen.exe'
      -'\smss.exe'
      -'\spoolsv.exe'
      -'\svchost.exe'
      -'\SystemSettingsBroker.exe'
      -'\taskhost.exe'
      -'\taskhostw.exe'
      -'\Taskmgr.exe'
      -'\TiWorker.exe'
      -'\vssadmin.exe'
      -'\w32tm.exe'
      -'\WerFault.exe'
      -'\WerFaultSecure.exe'
      -'\wermgr.exe'
      -'\wevtutil.exe'
      -'\wininit.exe'
      -'\winlogon.exe'
      -'\winrshost.exe'
      -'\WinRTNetMUAHostServer.exe'
      -'\wlanext.exe'
      -'\wlrmdr.exe'
      -'\WmiPrvSE.exe'
      -'\wslhost.exe'
      -'\WSReset.exe'
      -'\WUDFHost.exe'
      -'\WWAHost.exe'

  filter_main_generic:
    TargetFilename|contains:
      -'C:\$WINDOWS.~BT\'
      -'C:\$WinREAgent\'
      -'C:\Windows\SoftwareDistribution\'
      -'C:\Windows\System32\'
      -'C:\Windows\SysWOW64\'
      -'C:\Windows\WinSxS\'
      -'C:\Windows\uus\'

  filter_main_tiworker:
    Image|endswith:
      -'\TiWorker.exe'
      -'\wuaucltcore.exe'

    TargetFilename|startswith: 'C:\Windows\Temp\'
  filter_main_svchost:
    Image|endswith:
      -'C:\Windows\system32\svchost.exe'
      -'C:\Windows\SysWOW64\svchost.exe'

    TargetFilename|contains:
      -'C:\Program Files\WindowsApps\'
      -'C:\Program Files (x86)\WindowsApps\'
      -'\AppData\Local\Microsoft\WindowsApps\'

  filter_main_wuauclt:
    Image:
      -'C:\Windows\System32\wuauclt.exe'
      -'C:\Windows\SysWOW64\wuauclt.exe'
      -'C:\Windows\UUS\arm64\wuaucltcore.exe'

  filter_main_explorer:
    TargetFilename|endswith: 'C:\Windows\explorer.exe'
  filter_main_msiexec:
    Image|endswith:
      -'C:\WINDOWS\system32\msiexec.exe'
      -'C:\WINDOWS\SysWOW64\msiexec.exe'

    TargetFilename|startswith:
      -'C:\Program Files\PowerShell\7\pwsh.exe'
      -'C:\Program Files\PowerShell\7-preview\pwsh.exe'
      -'C:\Program Files\WindowsApps\Microsoft.PowerShellPreview\'

  filter_main_healtray:
    TargetFilename|contains: 'C:\Windows\System32\SecurityHealth\'
    TargetFilename|endswith: '\SecurityHealthSystray.exe'
    Image|endswith: '\SecurityHealthSetup.exe'
  filter_optional_wslhost:
TargetFilename:'C:\Program Files\WSL\wslhost.exe'     - TargetFilename|contains|all:
      - 'C:\Program Files\WindowsApps\MicrosoftCorporationII.WindowsSubsystemForLinux_'
      - '\wslhost.exe'
    - TargetFilename|contains|all:
      - 'C:\Users\'
      - '\AppData\Local\Microsoft\WindowsApps\'
      - '\wslhost.exe'
  condition:selection and not 1 of filter_main_* and not 1 of filter_optional_*
Falsepositives:
  -System processes copied outside their default folders for testing purposes
  -Third party software naming their software with the same names as the processes mentioned here
Level: medium