splunk-security_content/docs/_posts/2020-11-06-ryuk_test_files_detected.md

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

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Ryuk Test Files Detected	Data Encrypted for Impact	Endpoint	2020-11-06	true		Data Encrypted for Impact Impact Splunk Enterprise Splunk Enterprise Security Splunk Cloud

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Description

The search looks for files that contain the key word Ryuk under any folder in the C drive, which is consistent with Ryuk propagation.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel:
• Last Updated: 2020-11-06
• Author: Rod Soto, Jose Hernandez, Splunk
• ID: 57d44d70-28d9-4ed1-acf5-1c80ae2bbce3

ATT&CK

ID	Technique	Tactic
T1486	Data Encrypted for Impact	Impact

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem WHERE "Filesystem.file_path"=C:\\*Ryuk* BY "Filesystem.dest", "Filesystem.user", "Filesystem.file_path" 
| `drop_dm_object_name(Filesystem)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| `ryuk_test_files_detected_filter`

Associated Analytic Story

• Ryuk Ransomware

How To Implement

You must be ingesting data that records the filesystem activity from your hosts to populate the Endpoint Filesystem data-model object. If you are using Sysmon, you will need a Splunk Universal Forwarder on each endpoint from which you want to collect data.

Required field

• _time
• Filesystem.file_path
• Filesystem.dest
• Filesystem.user

Kill Chain Phase

• Delivery

Known False Positives

If there are files with this keywoord as file names it might trigger false possitives, please make use of our filters to tune out potential FPs.

RBA

Risk Score	Impact	Confidence	Message
70.0	70	100	A creation of ryuk test file file_path in host dest

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/ryuk/windows-sysmon.log

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