This analytic aims to identify potential adversaries who manipulate the security permissions of specific files or directories. This technique is frequently observed in the tradecraft of Advanced Persistent Threats (APTs) and coinminer scripts. By modifying the security permissions, adversaries seek to evade detection and impede access to their component files. Such actions indicate a deliberate effort to maintain control over compromised systems and hinder investigation or remediation efforts. Detecting these security permission changes can serve as a valuable indicator of an ongoing attack and enable timely response to mitigate the impact of the adversary's activities.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-06-06
- Author: Teoderick Contreras, Splunk
- ID: c76b796c-27e1-4520-91c4-4a58695c749e
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | 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`
The SPL above uses the following Macros:
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.
List of fields required to use this analytic.
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
|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 $dest$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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