This analytic is to detect a shred process to overwrite a files in a linux machine. Shred Linux application is designed to overwrite file to hide its contents or make the deleted file un-recoverable. Weve seen this technique in industroyer2 malware that tries to wipe energy facilities of targeted sector as part of its destructive attack. It might be some normal user may use this command for valid purposes but it is recommended to check what files, disk or folder it tries to shred that might be good pivot for incident response in this type of destructive malware.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-04-14
- Author: Teoderick Contreras, Splunk
- ID: c1952cf1-643c-4965-82de-11c067cbae76
Kill Chain Phase
- Actions On Objectives
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name =shred AND Processes.process IN ("*-n*", "*-u*", "*-z*", "*-s*") by Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid Processes.dest Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_shred_overwrite_command_filter`
The SPL above uses the following Macros:
linux_shred_overwrite_command_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
Administrator or network operator can use this application for automation purposes. Please update the filter macros to remove false positives.
Associated Analytic Story
|49.0||70||70||A possible shred overwrite command $process$ executed on $dest$|
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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