Detectionhightest
Legitimate Application Dropped Script
Detects programs on a Windows system that should not write scripts to disk
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François Hubaut, Florian Roth (Nextron Systems)Created Sun Aug 21Updated Thu Jun 227d604714-e071-49ff-8726-edeb95a70679windows
Log Source
WindowsFile Event
ProductWindows← raw: windows
CategoryFile Event← raw: file_event
Events for file system activity including creation, modification, and deletion.
Detection Logic
Detection Logic1 selector
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:
- '.ps1'
- '.bat'
- '.vbs'
- '.scf'
- '.wsf'
- '.wsh'
condition: selectionFalse Positives
Unknown
False positive likelihood has not been assessed. Additional context may be needed during triage.
References
MITRE ATT&CK
Tactics
Techniques
Rule Metadata
Rule ID
7d604714-e071-49ff-8726-edeb95a70679
Status
test
Level
high
Type
Detection
Created
Sun Aug 21
Modified
Thu Jun 22
Path
rules/windows/file/file_event/file_event_win_susp_legitimate_app_dropping_script.yml
Raw Tags
attack.defense-evasionattack.t1218