splunk-security_content/docs/_posts/2021-11-15-sdelete_application_execution.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Sdelete Application Execution	Data Destruction, File Deletion, Indicator Removal on Host	Endpoint	2021-11-15	true		Data Destruction Impact File Deletion Defense Evasion Indicator Removal on Host Defense Evasion Splunk Behavioral Analytics Endpoint_Processes

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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

ATT&CK

ID	Technique	Tactic
T1485	Data Destruction	Impact

| T1070.004 | File Deletion | Defense Evasion |

| T1070 | Indicator Removal on Host | Defense Evasion |

Search

| 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:

Note that 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 field

• _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

• Information Sabotage

Kill Chain Phase

• Exploitation

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.

Note that risk score is calculated base on the following formula: (Impact * Confidence)/100

Reference

• https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/
• https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1485/T1485.md

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1485/sdelete/security.log

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