Immutable Backups: The Best Protection Against Ransomware in 2025

Every day, businesses around the world are brought to a halt by ransomware attacks. In 2025 alone, these cyber threats have cost organizations billions of dollars. Even traditional backup systems are no longer safe. So, how can you ensure that your critical data remains accessible—even during a ransomware attack?

Two words: immutable backups.

What Is an Immutable Backup?

An immutable backup is a backup that cannot be modified or deleted for a defined period of time. Once the data is written, it’s locked—completely tamper-proof, even if an attacker gains admin access.

This approach is often based on WORM (Write Once, Read Many) technology. It means data can be written once and read as many times as needed, but never altered or overwritten.

Why Ransomware Targets Your Backups

Cybercriminals understand one thing clearly: if a business can restore its data, it won’t pay the ransom. That’s why modern ransomware doesn’t just go after production systems—it also targets backups.

Attackers aim to:

• Gain access to backup interfaces using stolen credentials
• Delete or encrypt backup copies
• Silently corrupt backups to make recovery impossible

Even backups stored in the cloud or on NAS devices are vulnerable if they’re not properly isolated or immutable.

How Do Immutable Backups Work?

Immutable backups rely on a combination of key technologies:

• Data locking: Once written, backup data is frozen for a specific retention period (e.g., 30 days).
• Non-editable retention: Even administrators cannot reduce or delete the retention window.
• Storage isolation: Backups are kept in secure, separate environments (such as object storage or air-gapped systems) that are inaccessible from compromised networks.
• Audit trails: All actions are logged, offering full visibility and accountability.

These measures ensure your backups remain intact—even if your entire system is compromised.

Real-World Benefits of Immutability

Implementing immutable backups delivers a wide range of benefits:

✅ Strong protection against ransomware
✅ Reliable and fast recovery after incidents
✅ Compliance with data protection regulations (GDPR, ISO 27001, DORA, etc.)
✅ Greater peace of mind for IT teams
✅ A powerful deterrent against cybercriminals

Immutability Built-In with Datashelter

At Datashelter, we’ve built our platform to be resilient by default—designed to withstand the latest cyber threats, including ransomware. Our backup solutions offer configurable immutability options tailored for small businesses and large enterprises alike.

Here’s how Datashelter keeps your data safe:

• Your data can only be deleted by retention policies you’ve defined.
• Backups are isolated in secure environments, fully shielded from external tampering.
• A simple interface lets you manage retention policies without complexity.
• If your Datashelter credentials are compromised, no backup data can be deleted, and you’ll receive instant email alerts about suspicious activity.

Most importantly, our infrastructure is proven, sovereign, regularly audited, and hosted entirely in Europe.

Conclusion: Immutability Is the Ultimate Cybersecurity Shield

In a world where ransomware is evolving faster than ever, immutable backups are no longer optional—they're essential. By ensuring your backup data cannot be altered or deleted, you empower your organization to recover quickly, without paying ransoms or risking data loss.

Don’t wait for an attack—make your backups immutable today.