This deep technical guide explains protocol architecture, encryption models, security risks, enterprise use cases, and deployment best practices.
1. FTP (File Transfer Protocol)
Definition
FTP is a traditional file transfer protocol that uses separate control and data channels. It operates without encryption by default.
Architecture
- Control channel: TCP port 21.
- Data channel: Separate dynamic port.
- Supports active and passive modes.
Security Risks
- Plaintext authentication.
- Susceptible to packet sniffing.
- Vulnerable to man-in-the-middle attacks.
Typical Use Cases
- Legacy systems.
- Public file downloads.
- Non-sensitive transfers.
2. SFTP (SSH File Transfer Protocol)
Definition
SFTP operates over SSH, providing secure file transfer through encrypted communication. Unlike FTP, it uses a single secure channel.
Architecture
- Single TCP connection.
- Runs over SSH (port 22).
- Full encryption of commands and data.
Security Benefits
- Strong encryption.
- Authentication via keys or passwords.
- Reduced attack surface.
Enterprise Use Cases
- Secure automation.
- Remote server management.
- Backup transfers.
3. FTPS (FTP over SSL/TLS)
Definition
FTPS extends FTP by adding SSL/TLS encryption to protect communication.
Architecture
- Separate control and data channels.
- Encrypted using SSL/TLS.
- Explicit or implicit modes.
Security Features
- Certificate-based authentication.
- Encrypted data transmission.
Enterprise Use Cases
- Compliance-driven environments.
- Secure web hosting transfers.
- Regulated industries.
4. Protocol Comparison
- FTP – No encryption, legacy protocol.
- SFTP – Secure, single channel, SSH-based.
- FTPS – Secure FTP using TLS encryption.
5. Security Architecture Differences
Encryption Model
- FTP – None.
- SFTP – SSH encryption.
- FTPS – TLS encryption.
Connection Complexity
- FTP/FTPS use multiple connections.
- SFTP uses single secure tunnel.
6. Network Security Perspective
- SFTP easier for firewall configuration.
- FTPS may require dynamic port management.
- FTP exposes credentials and data.
7. Red Team Risk Analysis
- FTP traffic easily intercepted.
- Credential harvesting possible.
- Misconfigured FTPS vulnerable to downgrade attacks.
8. Blue Team Defense Recommendations
- Disable FTP whenever possible.
- Use SFTP for secure automation.
- Enforce certificate validation for FTPS.
- Monitor file transfer logs.
9. Enterprise Architecture Best Practices
- Adopt Zero Trust file transfer policies.
- Use secure gateways.
- Implement identity-based access control.
Conclusion
Modern organizations should prioritize encrypted file transfer protocols. SFTP is often preferred due to its simplicity and strong security model, while FTPS remains useful in compliance-driven environments. FTP should only be used in controlled legacy scenarios.
