--- title: What Is an Immutable Backup? description: Learn how immutable backups protect your business from ransomware attacks and ensure data recovery, alongside essential strategies for effective backup management. image: https://www.tmgcinc.com/hubfs/immutable%20backup.webp --- [Skip to the main content.](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#main-content) [![TMGC\_Logo\_Main\_V1](https://www.tmgcinc.com/hs-fs/hubfs/Logos/TMGC_Logo_Main_V1.webp?width=130&height=112&name=TMGC_Logo_Main_V1.webp "TMGC_Logo_Main_V1")](https://www.tmgcinc.com/) [![TMGC\_Logo\_Main\_V1](https://www.tmgcinc.com/hs-fs/hubfs/Logos/TMGC_Logo_Main_V1.webp?width=150&height=129&name=TMGC_Logo_Main_V1.webp "TMGC_Logo_Main_V1")](https://www.tmgcinc.com/) - [Fractional IT Services](https://www.tmgcinc.com/fractional-it-services) - What We Do - [Complete IT Management](https://www.tmgcinc.com/fractional-it-services) - [Cybersecurity](https://www.tmgcinc.com/managed-cybersecurity-services) - [Service Desk](https://www.tmgcinc.com/it-help-desk-services) - [Data Protection & Recovery](https://www.tmgcinc.com/data-backup-recovery) - [Cloud & Hosting](https://www.tmgcinc.com/managed-cloud-hosting-services) - [Compliance Management](https://www.tmgcinc.com/it-compliance-services) - [IT Infrastructure](https://www.tmgcinc.com/it-infrastructure-management) - [Licensing & Software Management](https://www.tmgcinc.com/it-licensing-management) - [Device Management](https://www.tmgcinc.com/it-device-management) - Industries - [Manufacturing](https://www.tmgcinc.com/managed-it-services-manufacturing) - [AEC](https://www.tmgcinc.com/architecture-engineering-construction-it-services) - [Financial Services](https://www.tmgcinc.com/it-support-financial-services) - [Medical](https://www.tmgcinc.com/managed-it-services-medical-practices) - [Defense Contractors](https://www.tmgcinc.com/it-support-defense-contractors) - [Private Equity](https://www.tmgcinc.com/it-services-private-equity) - Resources - [About Us](https://www.tmgcinc.com/about) - [Blog](https://www.tmgcinc.com/blog) - [Case Studies](https://www.tmgcinc.com/case-studies) - [Guide to CMMC Compliance](https://www.tmgcinc.com/cmmc-compliance-everything-defense-contractors-need-to-know-in-2026) - [Guide to Workplace AI Security](https://www.tmgcinc.com/workplace-ai-security-guide) - [AI Readiness Quiz](https://www.tmgcinc.com/ai-security-readiness-quiz-tmgc) [GET STARTED](https://www.tmgcinc.com/contact) Toggle Menu Toggle Menu [GET STARTED](https://www.tmgcinc.com/contact) - [Fractional IT Services](https://www.tmgcinc.com/fractional-it-services) - What We Do - [Complete IT Management](https://www.tmgcinc.com/fractional-it-services) - [Cybersecurity](https://www.tmgcinc.com/managed-cybersecurity-services) - [Service Desk](https://www.tmgcinc.com/it-help-desk-services) - [Data Protection & Recovery](https://www.tmgcinc.com/data-backup-recovery) - [Cloud & Hosting](https://www.tmgcinc.com/managed-cloud-hosting-services) - [Compliance Management](https://www.tmgcinc.com/it-compliance-services) - [IT Infrastructure](https://www.tmgcinc.com/it-infrastructure-management) - [Licensing & Software Management](https://www.tmgcinc.com/it-licensing-management) - [Device Management](https://www.tmgcinc.com/it-device-management) - Industries - [Manufacturing](https://www.tmgcinc.com/managed-it-services-manufacturing) - [AEC](https://www.tmgcinc.com/architecture-engineering-construction-it-services) - [Financial Services](https://www.tmgcinc.com/it-support-financial-services) - [Medical](https://www.tmgcinc.com/managed-it-services-medical-practices) - [Defense Contractors](https://www.tmgcinc.com/it-support-defense-contractors) - [Private Equity](https://www.tmgcinc.com/it-services-private-equity) - Resources - [About Us](https://www.tmgcinc.com/about) - [Blog](https://www.tmgcinc.com/blog) - [Case Studies](https://www.tmgcinc.com/case-studies) - [Guide to CMMC Compliance](https://www.tmgcinc.com/cmmc-compliance-everything-defense-contractors-need-to-know-in-2026) - [Guide to Workplace AI Security](https://www.tmgcinc.com/workplace-ai-security-guide) - [AI Readiness Quiz](https://www.tmgcinc.com/ai-security-readiness-quiz-tmgc) [Linkedin](https://www.linkedin.com/company/the-millennium-group-computing/) 4 min read # What Is an Immutable Backup? [Tony DiDonato](https://www.tmgcinc.com/blog/author/tony-didonato) : November 13, 2026 [Ransomware Recovery](https://www.tmgcinc.com/blog/tag/ransomware-recovery) ![What Is an Immutable Backup?](https://www.tmgcinc.com/hubfs/immutable%20backup.webp) Almost every business we talk to tells us they have backups. My next question is the one that makes them think: could someone with your administrator password delete them? For most companies, the answer is yes. That's a problem, because attackers know it too. Sophos found that cybercriminals [tried to compromise backups in 94% of ransomware attacks](https://www.sophos.com/en-us/blog/the-impact-of-compromised-backups-on-ransomware-outcomes), and they succeeded more than half the time. That’s what immutable backups were created to eliminate. This post is part of our [ransomware recovery series](https://www.tmgcinc.com/blog/ransomware-recovery-business-owners-guide). It covers what immutable backups are, how they compare to air-gapped backups, and how to tell whether yours actually qualify.   ## Key Takeaways - An immutable backup can't be changed or deleted by anyone, including an attacker holding your admin passwords, until its retention period ends - Attackers target backups first because destroying them takes away your best option for recovering without paying - In a 2026 Omdia survey, 93% of tech leaders called fully immutable backup storage critical, but only 16% said they have it - Immutability works best alongside an offsite copy, separate credentials, and regular restore testing   ## Table of Contents 1. [What Is an Immutable Backup?](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#what) 2. [Why Do Attackers Go After Backups First?](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#why) 3. [Immutable vs. Air-Gapped Backup: What's the Difference?](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#difference) 4. [Why So Few Businesses Have Immutable Backups](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#few) 5. [How to Tell If Your Backups Are Actually Immutable](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#how) 6. [What Else Has to Be True for Recovery to Work](https://www.tmgcinc.com/blog/what-is-an-immutable-backup#recovery)   ## What Is an Immutable Backup? An immutable backup is a copy of your data that's locked for a set period of time. Until that period ends, nobody can edit, encrypt, or delete it. And nobody means *nobody*. A regular backup protects you from a failed hard drive or an accidental deletion. It doesn't protect you from someone who logs in as your administrator and wipes the backup server, which is exactly what ransomware groups try to do. You'll sometimes see immutability described as WORM storage (write once, read many) or a retention lock. The strongest versions are called "absolute" immutability, which means even the most privileged administrator, or an attacker who has stolen every password you own, can't shorten the lock or remove the data early.   ## Why Do Attackers Go After Backups First? Because [data backups](https://www.tmgcinc.com/data-backup-recovery) are what let you say no to a ransom demand. Take them away, and paying starts to look like the only way out. The same [Sophos research](https://www.techrepublic.com/de/article/ransomware-attackers-target-backups/) shows how much backups change the outcome. When attackers compromised a company's backups: - **The ransom demand more than doubled:** From a median of $1 million to $2.3 million. - **Companies were almost twice as likely to pay:** Without a clean copy, there's little room to negotiate. - **Recovery costs skyrocketed:** Median recovery costs went from $375,000 to $3 million. - **Recovery took longer:** Only 26% recovered fully within a week, compared with 46% of companies whose backups survived. Attackers usually get to backups the same way they get to everything else: [stolen credentials](https://www.tmgcinc.com/blog/guide-business-credential-theft). Once they have an admin login, they delete backup copies, shorten retention settings, or quietly corrupt backups for weeks before launching the encryption. We walked through what happens after that in our [ransomware recovery guide](https://www.tmgcinc.com/blog/ransomware-recovery-business-owners-guide).   ## Immutable vs. Air-Gapped Backup: What's the Difference? These terms get used interchangeably, but they protect you in different ways. An air-gapped backup is physically or logically disconnected from your network, so an attacker can't reach it. An immutable backup may be reachable, but it can't be changed.   | **Backup Type** | **How It Protects You** | **Where It Falls Short** | | --- | --- | --- | | Standard network backup | Quick restores of everyday files | Anyone with admin access can delete or encrypt it | | Cloud sync (OneDrive, Dropbox) | Easy file access from anywhere | Syncs encrypted or deleted files right along with good ones | | Air-gapped backup | Disconnected, so attackers can't reach it | Only as current as the last time it was connected; manual processes get skipped | | Immutable backup | Locked, so it can't be altered or deleted | Still needs an offsite copy if the whole site is lost | | Immutable and offsite | Locked copies stored away from your office | The strongest common setup, as long as it's tested |   The best setups use both ideas: an immutable copy stored somewhere separate from your main network, managed with credentials an attacker can't get from your everyday systems.   ## Why So Few Businesses Have Immutable Backups The 16% figure comes from [Omdia research](https://www.businesswire.com/news/home/20260901084268/en/Object-First-Sponsored-Omdia-Research-93-of-Technology-Leaders-Say-Absolutely-Immutable-Backup-Storage-Is-Critical-for-Ransomware-Protection-But-Only-16-Have-It) sponsored by Object First, a backup storage vendor. It surveyed 700 IT and business leaders in the U.S. and Europe in early 2026. Of those, 93% said fully immutable storage was critical for ransomware protection, while only 16% said their current backup storage met that standard. It’s really important to note that those respondents work at companies with 1,000 to 9,999 employees. Those companies usually have dedicated IT and security teams. For smaller businesses, the gap is almost always wider. The same survey found that 83% of organizations had suffered a successful ransomware attack in the past two years, and only 39% recovered at least three-quarters of their data afterward. In my experience, the gap usually comes down to a few things: - **Backups were set up years ago:** They haven't been revisited since ransomware groups started targeting them. - **"We're in the cloud" feels like enough:** Sync tools like OneDrive aren't true backups. - **Nobody owns the question:** The backup runs, the green checkmark shows up, and nobody asks what happens if an attacker gets admin access.   ## How to Tell If Your Backups Are Immutable Ask your IT provider these five questions. You want clear yes-or-no answers. 1. Can anyone, including your administrators, delete or change our backups before the retention period ends? 2. Is at least one copy stored offsite, away from our office network? 3. Are the backup system's logins separate from our everyday accounts, and protected with MFA? 4. How long are backups retained, and can that be shortened remotely? 5. When did we last do a full test restore, and how long did it take? If the answer to the first question is "yes" or "we'd have to check," your backups probably aren't immutable.   ## What Else Has to Be True for Recovery to Work Immutability keeps your backups from being destroyed, but it doesn't guarantee a fast recovery on its own. A few other pieces have to be in place: - **Regular restore testing:** A backup you've never restored is a backup you're hoping works. - **Clear recovery targets:** Know how much data you can afford to lose and how long each system can be down. - **Clean restores:** Make sure the backup you're restoring from predates the attacker's arrival, so you don't bring them back with it. - **Protected credentials:** MFA and monitoring on admin accounts make it much harder for anyone to reach your backups in the first place. With our [fractional IT services](https://www.tmgcinc.com/fractional-it-services), [data backup and recovery](https://www.tmgcinc.com/data-backup-recovery) runs out of our data center, and backups, monitoring, and restore testing are all part of one flat monthly rate. If you're not sure what would happen to your backups in an attack, [let's talk](https://www.tmgcinc.com/contact).   Our Story Our Story Started in 1999, The Millennium Group Computing is a proud veteran-owned business that is a complete technology solution provider. We are 100% committed to making sure business owners have the most reliable and professional IT service in Denver Metro. 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