Windows File and Directory Permissions Remove Inheritance

name: Windows File and Directory Permissions Remove Inheritance
id: 9b62da2c-e442-474f-83ca-fac4dabab1b3
version: 7
creation_date: '2023-04-12'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the removal of permission inheritance using ICACLS. This analytic identifies instances where ICACLS is used to remove permission inheritance from files or directories. The /inheritance:r flag, which strips inherited permissions while optionally preserving or altering explicit permissions, is monitored to detect changes that may restrict access or establish isolated permission configurations. Removing inheritance can be a legitimate administrative action but may also indicate an attempt to conceal malicious activity or bypass inherited security controls.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
search: |-
    | tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.process_name IN( "icacls.exe", "cacls.exe", "xcacls.exe")
        AND
        Processes.process = "*/inheritance:r*"
      BY Processes.action Processes.dest Processes.original_file_name
         Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
         Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
         Processes.process Processes.process_exec Processes.process_guid
         Processes.process_hash Processes.process_id Processes.process_integrity_level
         Processes.process_name Processes.process_path Processes.user
         Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_file_and_directory_permissions_remove_inheritance_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: Administrators or administrative scripts may use this application. Filter as needed.
references:
    - https://www.splunk.com/en_us/blog/security/-applocker-rules-as-defense-evasion-complete-analysis.html
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: A [$process_name$] was executed on [$dest$] attempting to remove inheritance permissions.
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Crypto Stealer
asset_type: Endpoint
mitre_attack_id:
    - T1222.001
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/T1222.001/icacls_inheritance/icacls_process_1.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit