Cisco NVM - Rclone Execution With Network Activity

name: Cisco NVM - Rclone Execution With Network Activity
id: 719f8c78-b20d-4bb9-8c33-6d1a762e7a9a
version: 5
date: '2026-03-10'
author: Nasreddine Bencherchali, Splunk
status: production
type: Anomaly
description: |
    This detection identifies execution of the file synchronization utility "rclone".
    It leverages Cisco Network Visibility Module logs, specifically flow data in order to capture process executions
    initiating network connections.
    While rclone is a legitimate command-line tool for syncing data to cloud storage providers, it has been widely abused by threat actors for data exfiltration.
    This analytic inspects process name and arguments for rclone and flags usage of suspicious flags.
    If matched, this could indicate malicious usage for stealthy data exfiltration or cloud abuse.
data_source:
    - Cisco Network Visibility Module Flow Data
search: |
    `cisco_network_visibility_module_flowdata`
    (
      process_name = "rclone.exe"
      OR
      (
        process_arguments = "* copy *"
        process_arguments = "*\\\\*"
        process_arguments IN ("*remote:*", "*mega:*", "*ftp:*", "*ftp1:*")
      )
      OR
      (
        process_arguments IN ("*remote:*", "*mega:*", "*ftp:*", "*ftp1:*")
        process_arguments = "*--transfers"
        process_arguments = "*--ignore-existing*"
        process_arguments = "*--auto-confirm*"
      )
    )
    | stats count min(_time) as firstTime max(_time) as lastTime
            values(parent_process_arguments) as parent_process_arguments
            values(process_arguments) as process_arguments
            values(parent_process_hash) as parent_process_hash
            values(process_hash) as process_hash
            values(module_name_list) as module_name_list
            values(module_hash_list) as module_hash_list
            values(dest_port) as dest_port
            values(aliul) as additional_logged_in_users_list
            values(dest_hostname) as dest_hostname
            by src dest parent_process_path parent_process_integrity_level process_path process_name process_integrity_level process_id transport
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | table
      parent_process_integrity_level parent_process_path parent_process_arguments parent_process_hash
      process_integrity_level process_path process_name process_arguments process_hash process_id
      additional_logged_in_users_list module_name_list module_hash_list
      src dest_hostname dest dest_port transport firstTime lastTime
    | `cisco_nvm___rclone_execution_with_network_activity_filter`
how_to_implement: |
    This search requires Network Visibility Module logs, which includes the flow data sourcetype.
    This search uses an input macro named `cisco_network_visibility_module_flowdata`.
    We strongly recommend that you specify your environment-specific configurations
    (index, source, sourcetype, etc.) for Cisco Network Visibility Module logs.
    Replace the macro definition with configurations for your Splunk environment.
    The search also uses a post-filter macro designed to filter out known false positives.
    The logs are to be ingested using the Splunk Add-on for Cisco Endpoint Security Analytics (CESA) (https://splunkbase.splunk.com/app/4221).
known_false_positives: |
    Rclone is used legitimately in some backup or other workflows. Tune this rule based on known-good operational usage or restrict by known user/service accounts an specific folders or remote names.
references:
    - https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
    - https://thedfirreport.com/2021/10/04/bazarloader-and-the-conti-leaks/
    - https://thedfirreport.com/2021/11/29/continuing-the-bazar-ransomware-story/
    - https://redcanary.com/blog/threat-detection/rclone-mega-extortion/
drilldown_searches:
    - name: View the detection results for - "$src$"
      search: '%original_detection_search% | search  src = "$src$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$src$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: Rclone was executed on $src$ using flags $process_arguments$ and connected to $dest_hostname$ over $dest_port$.
    risk_objects:
        - field: src
          type: system
          score: 20
    threat_objects:
        - field: process_name
          type: process_name
tags:
    analytic_story:
        - Scattered Lapsus$ Hunters
        - Cisco Network Visibility Module Analytics
    asset_type: Endpoint
    mitre_attack_id:
        - T1567.002
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test - Cisco NVM
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/cisco_network_visibility_module/cisco_nvm_flowdata/nvm_flowdata.log
          source: not_applicable
          sourcetype: cisco:nvm:flowdata