Immutable Backup

Immutable Backup is a backup that cannot be changed or deleted during a defined period of time. Immutability protects backup copies against manipulation, accidental deletion and attacks in which criminals deliberately encrypt or destroy backups.

Technically, immutability can be implemented through write-once-read-many storage, object-specific retention locks, separate administration roles or immutable snapshots. It is important that even privileged accounts cannot overwrite the protected data before the defined period expires. This preserves a trustworthy basis for recovery.

Common implementations are object lock mechanisms in object storage, WORM storage and hardened backup appliances; in addition, air gap concepts further isolate the backups from the production environment. Immutability is often recommended as part of the extended 3-2-1 Rule (3-2-1-1-0). Immutable backups are thus a central building block for Ransomware Protection and belong in every resilient strategy for Data Management.