Best NAS Devices for Ransomware Protection

Ransomware attacks on small and mid-sized businesses have skyrocketed, with attackers specifically targeting local backups and networked storage to maximize leverage. The right NAS device — configured properly — can be your last line of defense, keeping immutable backups that ransomware simply cannot touch.

What Makes a NAS Device Ransomware-Resistant?

Not every NAS is built with ransomware in mind. The key features that separate a ransomware-resistant NAS from a standard one:

• Immutable snapshots: Point-in-time backups that cannot be deleted or modified by ransomware
• Air-gap capability: Ability to disconnect from the network on a schedule
• WORM storage: Write-once-read-many volumes
• Anomaly detection: Built-in ransomware detection based on file entropy and access patterns
• Offsite replication: Syncing to a second location or cloud

Best NAS Devices for Ransomware Protection in 2025

1. Synology DS923+ – Best Overall for SMB Ransomware Protection

Synology’s DSM operating system includes Snapshot Replication with immutable snapshots, Active Backup for Business, and the Synology C2 cloud offsite option. The DS923+ hardware supports up to 4 drives with expansion capability, and DSM’s ransomware detection alerts you the moment suspicious file activity is detected.

• Bays: 4 (expandable)
• CPU: AMD Ryzen R1600
• Key features: Immutable snapshots, ransomware detection, C2 backup
• Price: ~$550 (diskless)

2. QNAP TS-464 – Best for Advanced Ransomware Defense

QNAP’s Security Counselor, combined with their VJBOD Cloud and NetBak Replicator tools, makes the TS-464 a powerful ransomware recovery platform. QNAP supports both WORM volumes and immutable snapshots via the QuTS hero ZFS-based OS variant.

• Bays: 4
• CPU: Intel Celeron N5105
• Key features: WORM, ZFS snapshots, Security Counselor
• Price: ~$500 (diskless)

3. Synology RS1221+ – Best for Rack-Mounted Business Deployments

For businesses with a server room, the RS1221+ brings enterprise-grade backup and snapshot technology in a rack-mount form factor. With 8 bays and support for SSD caching, this unit handles heavy backup workloads while maintaining immutable recovery points.

• Bays: 8
• Form factor: 2U rack
• CPU: AMD Ryzen V1500B
• Price: ~$1,200 (diskless)

4. TerraMaster F4-423 – Best Budget Ransomware-Resistant NAS

TerraMaster’s TOS 5 operating system now includes snapshot-based backup and real-time ransomware guards, bringing solid protection at a lower price point than Synology or QNAP. The F4-423 is a capable 4-bay unit ideal for small offices.

• Bays: 4
• CPU: Intel Celeron N5105
• Price: ~$350 (diskless)

5. Asustor Lockerstor 4 Gen2 – Best for Home + Office Hybrid

Asustor’s ADM OS supports immutable snapshots and their DataSync service for offsite replication. The Lockerstor 4 Gen2 features 2.5GbE networking and NVMe SSD caching slots for fast backup throughput.

• Bays: 4 + 2x M.2 NVMe
• Networking: 2x 2.5GbE
• Price: ~$420 (diskless)

Ransomware-Proofing Your NAS: Configuration Best Practices

Even the best NAS can be compromised without proper configuration. Follow these rules:

1. Enable immutable snapshots on all shared folders
2. Use a dedicated backup VLAN isolated from your main network
3. Never expose NAS admin interfaces to the public internet
4. Enable 2FA on the NAS admin account
5. Schedule automated offsite replication to cloud or a second NAS
6. Test restores quarterly