System File Execution Location Anomaly

title: System File Execution Location Anomaly
id: e4a6b256-3e47-40fc-89d2-7a477edd6915
related:
    - id: be58d2e2-06c8-4f58-b666-b99f6dc3b6cd # Dedicated SvcHost rule
      type: derived
status: test
description: |
    Detects the execution of a Windows system binary that is usually located in the system folder from an uncommon location.
references:
    - https://twitter.com/GelosSnake/status/934900723426439170
    - https://asec.ahnlab.com/en/39828/
    - https://www.splunk.com/en_us/blog/security/inno-setup-malware-redline-stealer-campaign.html
author: Florian Roth (Nextron Systems), Patrick Bareiss, Anton Kutepov, oscd.community, Nasreddine Bencherchali (Nextron Systems)
date: 2017-11-27
modified: 2026-02-12
tags:
    - attack.stealth
    - attack.t1036
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\atbroker.exe'
            - '\audiodg.exe'
            - '\bcdedit.exe'
            - '\bitsadmin.exe'
            - '\certreq.exe'
            - '\certutil.exe'
            - '\cmstp.exe'
            - '\conhost.exe'
            - '\consent.exe'
            - '\cscript.exe'
            - '\csrss.exe'
            - '\dashost.exe'
            - '\defrag.exe'
            - '\dfrgui.exe' # Was seen used by Lazarus Group - https://asec.ahnlab.com/en/39828/
            - '\dism.exe'
            - '\dllhost.exe'
            - '\dllhst3g.exe'
            - '\dwm.exe'
            - '\eventvwr.exe'
            - '\fsquirt.exe' # was seen used by sidewinder APT - https://securelist.com/sidewinder-apt/114089/
            - '\finger.exe'
            - '\logonui.exe'
            - '\LsaIso.exe'
            - '\lsass.exe'
            - '\lsm.exe'
            - '\msiexec.exe'
            - '\ntoskrnl.exe'
            - '\powershell_ise.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\runonce.exe'
            - '\RuntimeBroker.exe'
            - '\schtasks.exe'
            - '\services.exe'
            - '\sihost.exe'
            - '\smartscreen.exe'
            - '\smss.exe'
            - '\spoolsv.exe'
            - '\svchost.exe'
            - '\taskhost.exe'
            - '\taskhostw.exe'
            - '\Taskmgr.exe'
            - '\userinit.exe'
            - '\werfault.exe'
            - '\werfaultsecure.exe'
            - '\wininit.exe'
            - '\winlogon.exe'
            - '\winver.exe'
            - '\wlanext.exe'
            - '\wscript.exe'
            - '\wsl.exe'
            - '\wsmprovhost.exe' # Was seen used by Lazarus Group - https://asec.ahnlab.com/en/39828/
    filter_main_generic:
        Image|startswith:
            - 'C:\$WINDOWS.~BT\'
            - 'C:\$WinREAgent\'
            - 'C:\Windows\SoftwareDistribution\'
            - 'C:\Windows\System32\'
            - 'C:\Windows\SystemTemp\'
            - 'C:\Windows\SysWOW64\'
            - 'C:\Windows\uus\'
            - 'C:\Windows\WinSxS\'
    filter_optional_system32:
        Image|contains: '\SystemRoot\System32\'
    filter_main_powershell:
        Image|contains:
            - 'C:\Program Files\PowerShell\7\'
            - 'C:\Program Files\PowerShell\7-preview\'
            - 'C:\Program Files\WindowsApps\Microsoft.PowerShellPreview'
            - '\AppData\Local\Microsoft\WindowsApps\Microsoft.PowerShellPreview' # pwsh installed from Microsoft Store
        Image|endswith: '\pwsh.exe'
    filter_main_wsl_programfiles:
        Image|startswith:
            - 'C:\Program Files\WindowsApps\MicrosoftCorporationII.WindowsSubsystemForLinux'
            - 'C:\Program Files\WSL\'
        Image|endswith: '\wsl.exe'
    filter_main_wsl_appdata:
        Image|startswith: C:\Users\'
        Image|contains: '\AppData\Local\Microsoft\WindowsApps\'
        Image|endswith: '\wsl.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_susp_system_exe_anomaly/info.yml