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Description

The following analytic identifies the modification of security permissions on files or directories using tools like icacls.exe, cacls.exe, or xcacls.exe. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line executions. This activity is significant as it is commonly used by Advanced Persistent Threats (APTs) and coinminer scripts to evade detection and maintain control over compromised systems. If confirmed malicious, this behavior could allow attackers to hinder investigation, impede remediation efforts, and maintain persistent access to the compromised environment.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-21
  • Author: Teoderick Contreras, Splunk
  • ID: c76b796c-27e1-4520-91c4-4a58695c749e

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1222.001 Windows File and Directory Permissions Modification Defense Evasion
T1222 File and Directory Permissions Modification Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| 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 ("*:R*", "*:W*", "*:F*", "*:C*",, "*:N*","*/P*", "*/E*") by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_guid Processes.dest Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_files_and_dirs_access_rights_modification_via_icacls_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_files_and_dirs_access_rights_modification_via_icacls_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.process_name
  • Processes.process
  • Processes.process_guid
  • Processes.dest
  • Processes.user
  • Processes.process_id
  • Processes.process

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

Unknown. It is possible some administrative scripts use ICacls. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 Process name $process_name$ with access right modification argument executed by $user$ to change security permission of a specific file or directory on host $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 2