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.

Techniques

T1567.002

Sample rules

Cisco NVM - Rclone Execution With Network Activity

source: splunk
technicques:
- T1567.002

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.

Detection logic

`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`