cloudimg SFTP Server - Hardened OpenSSH File Transfer

This is a repackaged open source software product wherein additional charges apply for cloudimg support services.

Deploy a fully configured, security-hardened SFTP file transfer server on your own EC2 instance within minutes. Built on OpenSSH - the secure shell suite trusted across the internet - this AMI eliminates the manual sshd_config editing of a bare install and avoids the per-user monthly fees of managed services. You retain full control over your instance, storage, and network configuration with no vendor lock-in.

Unlike managed SFTP services, this server runs on infrastructure you own. There are no per-protocol-hour charges, no per-GB transfer fees beyond standard EC2 networking, and no user-count tiers. Teams in healthcare, financial services, and logistics use this approach to maintain compliance control while keeping costs predictable at scale. A healthcare billing team, for example, can receive nightly claim files from 50+ provider offices - each confined to their own chroot directory with quota limits - while the audit log feeds into a SIEM for HIPAA evidence collection.

Every SFTP user is locked into their own home directory with an OpenSSH chroot jail. Users can only see and write inside their own space, never the rest of the filesystem, and are given no interactive shell. User home directories live on a dedicated, independently resizable EBS volume kept separate from the operating system disk, so you can scale storage without touching the OS.

The image ships key-only - the secure default. Users authenticate with an SSH key out of the box, and password authentication can be enabled for SFTP users with a single command. The administrator account always stays key-only. SSH keys for SFTP users are managed in a central, root-owned location outside every jail, so file ownership rules are always correct.

A bundled CLI toolkit makes day-to-day operation simple:

• sftp-adduser - create a user with an SSH key or a generated password
• sftp-deluser - remove a user and optionally their data
• sftp-listusers - list users and their disk usage
• sftp-passwd - reset or lock passwords
• sftp-password-auth - enable or disable password logins globally

No manual config file editing required. These tools are the primary interface to the server.

The server ships with fail2ban brute-force protection that bans repeat offenders, per-user disk quotas so one account cannot fill the volume, and transfer audit logging that records every upload, download, and delete to the system journal. Password authentication is off by default and all forwarding features are disabled.

A per-instance demo user is created on first boot with a fresh SSH key unique to the instance, stored in a root-only file. Confirm the server works immediately, then remove the demo user once your own accounts exist. The included user guide covers creating key-based and password-based users, the chroot model, quotas, reading the audit log, and connecting from common SFTP clients.

This AMI integrates naturally with your existing AWS environment. Place it in a private subnet behind a Network Load Balancer, restrict inbound traffic to port 22 via Security Groups, and attach additional EBS volumes as your user base grows. CloudWatch can ingest the audit journal for centralized monitoring.

Want help designing your file transfer architecture or onboarding your first users? Contact cloudimg for a free guided setup session. Our engineers will walk you through instance sizing, security group configuration, user provisioning, and audit log integration - so you reach production faster.

• Partner file exchange - Onboard external partners into isolated chroot directories with individual quotas, replacing insecure email attachments or shared FTP servers
• Compliance-focused transfer - Capture a full audit trail of every file operation for regulatory evidence in healthcare, finance, or legal workflows
• Application upload targets - Provide a stable SFTP endpoint for automated batch uploads from ERP, billing, or ETL systems
• Backup and archive ingestion - Accept nightly backup streams from on-premises systems into dedicated per-source directories

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