Icacls Deny Command

name: Icacls Deny Command
id: cf8d753e-a8fe-11eb-8f58-acde48001122
version: 14
creation_date: '2021-05-07'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: |
    The following analytic detects instances where an adversary modifies
    security permissions of a file or directory using commands like "icacls.exe", "cacls.exe",
    or "xcacls.exe" with deny options. It leverages data from Endpoint Detection and
    Response (EDR) agents, focusing on process names and command-line executions. This
    activity is significant as it is commonly used by Advanced Persistent Threats (APTs)
    and coinminer scripts to evade detection and impede access to critical files. If
    confirmed malicious, this could allow attackers to maintain persistence and hinder
    incident response efforts.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
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 IN ("*/deny*", "*/d:*", "*/d ")
    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)`
    | `icacls_deny_command_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: No false positives have been identified at this time. Filter as needed.
references:
    - https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search  dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") | 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: Process name $process_name$ with deny argument executed by $user$ to change security permission of a specific file or directory on host $dest$
        - field: user
          type: user
          score: 20
          message: Process name $process_name$ with deny argument executed by $user$ to change security permission of a specific file or directory on host $dest$
analytic_story:
    - Azorult
    - Sandworm Tools
    - Compromised Windows Host
    - XMRig
    - Crypto Stealer
    - Defense Evasion or Unauthorized Access Via SDDL Tampering
asset_type: Endpoint
mitre_attack_id:
    - T1222
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/malware/xmrig_miner/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit