Legitimate Application Dropped Executable

 1title: Legitimate Application Dropped Executable
 2id: f0540f7e-2db3-4432-b9e0-3965486744bc
 3status: experimental
 4description: Detects programs on a Windows system that should not write executables to disk
 5references:
 6    - https://github.com/Neo23x0/sysmon-config/blob/3f808d9c022c507aae21a9346afba4a59dd533b9/sysmonconfig-export-block.xml#L1326
 7author: frack113, Florian Roth (Nextron Systems)
 8date: 2022/08/21
 9modified: 2023/06/22
10tags:
11    - attack.defense_evasion
12    - attack.t1218
13logsource:
14    product: windows
15    category: file_event
16detection:
17    selection:
18        Image|endswith:
19            # Microsoft Office Programs Dropping Executables / Rest of the apps are covered in: c7a74c80-ba5a-486e-9974-ab9e682bc5e4
20            - '\eqnedt32.exe'
21            - '\wordpad.exe'
22            - '\wordview.exe'
23            # LOLBINs that can be used to download executables
24            - '\certutil.exe'
25            - '\certoc.exe'
26            - '\CertReq.exe'
27            # - \bitsadmin.exe (depends on the environment; comment in if you're sure that bitsadmin doesn't do that in your env)
28            - '\Desktopimgdownldr.exe'
29            - '\esentutl.exe'
30            # - \expand.exe
31            - '\mshta.exe'
32            # 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)
33            - '\AcroRd32.exe'
34            - '\RdrCEF.exe'
35            - '\hh.exe'
36            - '\finger.exe'
37        TargetFilename|endswith:
38            - '.exe'
39            - '.dll'
40            - '.ocx'
41    condition: selection
42falsepositives:
43    - Unknown
44level: high