splunk-security_content/docs/_posts/2021-05-13-detect_rclone_command-line_usage.md

title, excerpt, categories, last_modified_at, toc, tags

title	excerpt	categories	last_modified_at	toc	tags
Detect RClone Command-Line Usage	Automated Exfiltration	Endpoint	2021-05-13	true	TTP T1020 Automated Exfiltration Exfiltration Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint Exfiltration

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Description

This analytic identifies commonly used command-line arguments used by rclone.exe to initiate a file transfer. Some arguments were negated as they are specific to the configuration used by adversaries. In particular, an adversary may list the files or directories of the remote file share using ls or lsd, which is not indicative of malicious behavior. During triage, at this stage of a ransomware event, exfiltration is about to occur or has already. Isolate the endpoint and continue investigating by review file modifications and parallel processes.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-05-13
• Author: Michael Haag, Splunk
• ID: 32e0baea-b3f1-11eb-a2ce-acde48001122

ATT&CK

ID	Technique	Tactic
T1020	Automated Exfiltration	Exfiltration

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process IN ("*copy*", "*mega*", "*pcloud*", "*ftp*", "*--config*", "*--progress*", "*--no-check-certificate*", "*--ignore-existing*", "*--auto-confirm*", "*--transfers*", "*--multi-thread-streams*")  by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process   Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
|  `security_content_ctime(lastTime)` 
| `detect_rclone_command_line_usage_filter`

Associated Analytic Story

• DarkSide Ransomware
• Ransomware

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.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_id

Kill Chain Phase

• Exfiltration

Known False Positives

There is potential for false positives as these arguments may be used by other applications. Filter or tune the analytic as needed.

RBA

Risk Score	Impact	Confidence	Message
35.0	50	70	An instance of parent_process_name spawning process_name was identified on endpoint dest by user user attempting to connect to a remote cloud service to move files or folders.

Reference

• https://redcanary.com/blog/rclone-mega-extortion/
• https://www.fireeye.com/blog/threat-research/2021/05/shining-a-light-on-darkside-ransomware-operations.html
• https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/

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/T1020/windows-sysmon.log

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