name: Detect RClone Command-Line Usage
id: e8b74268-5454-11ec-a799-acde48001122
version: 1
date: '2021-12-03'
author: Michael Haag, Splunk
type: TTP
datamodel:
- Endpoint_Processes
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.
search: '| from read_ssa_enriched_events() | where "Endpoint_Processes" IN(_datamodels)
  | eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)),
  cmd_line=ucast(map_get(input_event, "process"), "string", null), process_name=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), event_id=ucast(map_get(input_event, "event_id"), "string", null)
  | where cmd_line IS NOT NULL AND process_name IS NOT NULL AND process_name="rclone.exe"
  AND (like (cmd_line, "%copy%") OR like (cmd_line, "%mega%")OR like (cmd_line, "%pcloud%")
  OR like (cmd_line, "%ftp%") OR like (cmd_line, "%--config%") OR like (cmd_line,
  "%--progress%") OR like (cmd_line, "%--no-check-certificate%") OR like (cmd_line,
  "%--ignore-existing%") OR like (cmd_line, "%--auto-confirm%") OR like (cmd_line,
  "%--transfers%") OR like (cmd_line, "%--multi-thread-streams%")) | 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))
  | eval body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name",
  process_name, "parent_process_name", parent_process_name, "process_path", process_path])
  | into write_ssa_detected_events();'
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_Processess` datamodel.
known_false_positives: False positives should be limited as this is restricted to
  the Rclone process name. Filter or tune the analytic as needed.
references:
- https://redcanary.com/blog/rclone-mega-extortion/
- https://www.mandiant.com/resources/shining-a-light-on-darkside-ransomware-operations
- https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
- https://thedfirreport.com/2021/11/29/continuing-the-bazar-ransomware-story/
tags:
  analytic_story:
  - DarkSide Ransomware
  - Ransomware
  - Insider Threat
  cis20: []
  confidence: 70
  context:
  - Source:Endpoint
  - Stage:Exfiltration
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1020/windows-security.log
  impact: 50
  kill_chain_phases:
  - Exploitation
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest_device_id$ by user $dest_user_id$ attempting to connect to a
    remote cloud service to move files or folders.
  mitre_attack_id:
  - T1020
  nist: []
  observable:
  - name: dest_user_id
    type: User
    role:
    - Victim
  - name: dest_device_id
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Parent Process
  - name: process_name
    type: Process
    role:
    - Child Process
  product:
  - Splunk Behavioral Analytics
  required_fields:
  - _time
  - dest_device_id
  - process_name
  - parent_process_name
  - process_path
  - dest_user_id
  - process
  - cmd_line
  risk_score: 35
  risk_severity: low
  security_domain: endpoint
  asset_type: Endpoint