Detection rules › Splunk

Windows Mock Trusted Directory MSC File Creation

Status
production
Severity
medium
Group by
CreationUtcTime, computer_name, event_action, file_name, process_guid, process_id, process_name, target_filename, user, vendor_product
Author
Raven Tait, Splunk
Source
github.com/splunk/security_content

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.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body splunk

name: Windows Mock Trusted Directory MSC File Creation
id: de8cc077-2dba-4060-af78-c98b3cfc5407
version: 2
creation_date: '2026-05-05'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
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.
data_source:
    - Sysmon EventID 11
search: |-
    | 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`
how_to_implement: 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.
references:
    - https://www.fortinet.com/blog/threat-research/fickle-stealer-distributed-via-multiple-attack-chain
drilldown_searches:
    - earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
      name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: MSC file created in a mock trusted directory at $file_path$ on $dest$.
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: file_path
      type: file_path
analytic_story:
    - Windows Persistence Techniques
    - Windows Privilege Escalation
asset_type: Endpoint
mitre_attack_id:
    - T1218.014
    - T1548.002
    - T1574
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.014/snapattack/snapattack.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| 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

Stage 2: search

| `drop_dm_object_name(Filesystem)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_mock_trusted_directory_msc_file_creation_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Filesystem.file_pathin
  • "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"