file_event_win_susp_legitimate_app_dropping_exe.yml

title: Legitimate Application Dropped Executable
id: f0540f7e-2db3-4432-b9e0-3965486744bc
status: test
description: Detects programs on a Windows system that should not write executables to disk
references:
    - https://github.com/Neo23x0/sysmon-config/blob/3f808d9c022c507aae21a9346afba4a59dd533b9/sysmonconfig-export-block.xml#L1326
author: frack113, Florian Roth (Nextron Systems)
date: 2022/08/21
modified: 2023/06/22
tags:
    - attack.defense_evasion
    - attack.t1218
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith:
            # Microsoft Office Programs Dropping Executables / Rest of the apps are covered in: c7a74c80-ba5a-486e-9974-ab9e682bc5e4
            - '\eqnedt32.exe'
            - '\wordpad.exe'
            - '\wordview.exe'
            # LOLBINs that can be used to download executables
            - '\certutil.exe'
            - '\certoc.exe'
            - '\CertReq.exe'
            # - \bitsadmin.exe (depends on the environment; comment in if you're sure that bitsadmin doesn't do that in your env)
            - '\Desktopimgdownldr.exe'
            - '\esentutl.exe'
            # - \expand.exe
            - '\mshta.exe'
            # Executables that should never drop an executable to disk (but may after a previous process injection or if it's malware that uses a legitimate name)
            - '\AcroRd32.exe'
            - '\RdrCEF.exe'
            - '\hh.exe'
            - '\finger.exe'
        TargetFilename|endswith:
            - '.exe'
            - '.dll'
            - '.ocx'
    condition: selection
falsepositives:
    - Unknown
level: high