Windows Mock Trusted Directory MSC File Creation
Description
Detects the creation of MSC files within a "C:\Windows \System32" directory. Due to how Windows parses paths, the space causes an execution flow hijack and a malicious file will be executed instead of the standard Windows Files.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Filesystem where
Filesystem.file_path IN (
"C:\\Windows \\System32\\*.msc",
"C:\\Windows \\System32\\de-DE\\*.msc",
"C:\\Windows \\System32\\en-US\\*.msc",
"C:\\Windows \\System32\\es-ES\\*.msc",
"C:\\Windows \\System32\\fr-FR\\*.msc",
"C:\\Windows \\System32\\it-IT\\*.msc",
"C:\\Windows \\System32\\ja-JP\\*.msc",
"C:\\Windows \\System32\\ko-KR\\*.msc",
"C:\\Windows \\System32\\zh-CN\\*.msc",
"C:\\Windows \\System32\\zh-TW\\*.msc"
)
by Filesystem.dest Filesystem.file_create_time Filesystem.process_path
Filesystem.process_guid Filesystem.process_id Filesystem.file_path Filesystem.file_name
Filesystem.user Filesystem.vendor_product Filesystem.action
| `drop_dm_object_name(Filesystem)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_mock_trusted_directory_msc_file_creation_filter`
Implementation guide
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known false positives
- Some legitimate software installers or system maintenance tools may create MSC files in the System32 directory with unusual paths. Verify and allow trusted system or vendor-approved processes to reduce false positives.
Analyst notes
Known false positives: Some legitimate software installers or system maintenance tools may create MSC files in the System32 directory with unusual paths. Verify and allow trusted system or vendor-approved processes to reduce false positives.