--- title: Immutable Storage date: 2026-06-01T17:19:00+02:00 author: Hannes Heckel canonical_url: "https://www.fast-lta.de/en/glossary/immutable-storage" section: Glossar --- In the context of ransomware protection and compliance archiving, immutable storage is a central concept — but a misunderstood one. Not all forms of immutability are equivalent. Software WORM / Object Lock: immutability is enforced through software policies — retention policies, Object Lock, immutability flags. In Governance Mode, administrators with sufficient rights can lift these policies. In Compliance Mode with Multi-Person Authorization, this is harder, but immutability remains a configuration setting. With compromised admin credentials or zero-days in the management layer, immutability can be overridden. Hardware WORM: immutability is enforced at device level, independent of operating system, firmware, drivers or user privileges. Silent Cubes from FAST LTA enforce hardware WORM at firmware level: once written, data is physically immutable. No administrator, no root access, no software update can modify written data. The consequence for practice and compliance: software WORM meets compliance requirements formally (DORA Art. 12) — but only in combination with documented organizational measures. Hardware WORM meets these requirements technically, independent of organizational measures. In a tax audit, legal dispute or regulatory review, hardware WORM is the more robust position. ### Audit-Proof Archiving Audit-proof archiving describes the legally required property of an archiving system that preserves documents completely, immutably, traceably and accessibly at all times — and that this can be demonstrated without gaps to tax authorities, auditors and data protection supervisory bodies. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/audit-proof-archiving) ### WORM WORM (Write Once, Read Many) refers to a storage principle in which data is written once and can technically no longer be altered or deleted — in hardware WORM, this immutability is a physical property of the storage controller, independent of software, operating system or user privileges. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/worm) ### WORM WORM (Write Once, Read Many) refers to a storage principle in which data is written once and can technically no longer be altered or deleted — in hardware WORM, this immutability is a physical property of the storage controller, independent of software, operating system or user privileges. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/worm) ### WORM WORM (Write Once, Read Many) refers to a storage principle in which data is written once and can technically no longer be altered or deleted — in hardware WORM, this immutability is a physical property of the storage controller, independent of software, operating system or user privileges. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/worm) ### DORA DORA (Digital Operational Resilience Act, EU 2022/2554) is an EU regulation that has applied to all regulated financial market participants since January 2025, setting concrete requirements for ICT risk management, backup systems (Art. 11 and 12), third-party provider management (Art. 28–30) and incident reporting. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/dora) ### WORM WORM (Write Once, Read Many) refers to a storage principle in which data is written once and can technically no longer be altered or deleted — in hardware WORM, this immutability is a physical property of the storage controller, independent of software, operating system or user privileges. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/worm) ### WORM WORM (Write Once, Read Many) refers to a storage principle in which data is written once and can technically no longer be altered or deleted — in hardware WORM, this immutability is a physical property of the storage controller, independent of software, operating system or user privileges. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/worm) ### WORM WORM (Write Once, Read Many) refers to a storage principle in which data is written once and can technically no longer be altered or deleted — in hardware WORM, this immutability is a physical property of the storage controller, independent of software, operating system or user privileges. [Mehr erfahren →](https://www.fast-lta.de/en/glossary/worm) ## Frequently asked questions #### What is the difference between Object Lock and hardware WORM? Object Lock is a software-enforced lock function used in S3-compatible storage systems and cloud services. In Governance Mode, an admin with sufficient rights can override the retention. In Compliance Mode it is harder, but it remains a software policy. Hardware WORM enforces immutability in the hardware controller — no software, no operating system, no user account can modify written data. #### Does immutable storage protect against ransomware? Partially. Immutable storage protects data from being encrypted or deleted — but only as long as the protection is active and the system is reachable. Software-based immutability can be overridden by an attacker with compromised admin credentials. Hardware WORM provides stronger protection, but the system remains addressable via the network. The most complete protection is the combination of hardware WORM and physical air gap: immutable and physically unreachable.