Name:Cisco NVM - Rclone Execution With Network Activity id:719f8c78-b20d-4bb9-8c33-6d1a762e7a9a version:1 date:2025-07-03 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:'$info_max_time$' tags: analytic_story: - 'Cisco Network Visibility Module Analytics' asset_type:Endpoint mitre_attack_id: - 'T1567.002' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' security_domain:endpoint
