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Description

This analytic will detect the execution of sdelete.exe attempting to delete potentially important files that may related to adversary or insider threats to destroy evidence or information sabotage. Sdelete is a SysInternals utility meant to securely delete files on disk. This tool is commonly used to clear tracks and artifact on the targeted host.

  • Type: Anomaly
  • Product: Splunk Behavioral Analytics
  • Datamodel: Endpoint_Processes
  • Last Updated: 2021-11-15
  • Author: Teoderick Contreras, Splunk
  • ID: fcc52b9a-4616-11ec-8454-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1485 Data Destruction Impact
T1070.004 File Deletion Defense Evasion
T1070 Indicator Removal Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE 


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| from read_ssa_enriched_events() 
| eval timestamp=parse_long(ucast(map_get(input_event,"_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"), "string", null)), process_name=lower(ucast(map_get(input_event, "process_name"), "string", null)), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string", null), parent_cmd_line=ucast(map_get(input_event, "parent_process"), "string", null), event_id=ucast(map_get(input_event, "event_id"), "string", null) 
| where cmd_line IS NOT NULL AND process_name IS NOT NULL AND like(process_name, "%sdelete%") AND (like (cmd_line, "%-c %") OR like (cmd_line, "%-f %")OR like (cmd_line, "%-p %") OR like (cmd_line, "%-r %") OR like (cmd_line, "%-q %") OR like (cmd_line, "%-s %") OR like (cmd_line, "%-z %") OR like (cmd_line, "%/accepteula%") OR like (cmd_line, "%-nobanner%")OR like (cmd_line, "%.doc%")OR like (cmd_line, "%.xls%") OR like (cmd_line, "%.ppt%")OR like (cmd_line, "%.rtf%") OR like (cmd_line, "%.pdf%") OR like (cmd_line, "%.key%")OR like (cmd_line, "%.log%") OR like (cmd_line, "%.txt%") OR like (cmd_line, "%.jpg%") OR like (cmd_line, "%.png%") OR like (cmd_line, "%.gif%") OR like (cmd_line, "%.bmp%") OR like (cmd_line, "%.7z%")  OR like (cmd_line, "%.zip%") OR like (cmd_line, "%.rar%") OR like (cmd_line, "%.tar%") OR like (cmd_line, "%.gz%") OR like (cmd_line, "%.xls%")) 
| eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)), body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "process_path", process_path, "parent_process_name", parent_process_name, "parent_cmd_line", parent_cmd_line]) 
| into write_ssa_detected_events();

Macros

The SPL above uses the following Macros:

:information_source: sdelete_application_execution_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
  • dest
  • user
  • parent_process_name
  • parent_process
  • process_name
  • process
  • process_id
  • process_path
  • cmd_line

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

False positives should be limited, filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
42.0 60 70 Sdelete process $process_name$ executed on $dest_device_id$ attempting to permanently delete files by $dest_user_id$.

: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

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