Ransomware-resistant backups: a practical guide for UK SMEs

Ransomware is no longer a remote IT problem for big corporations — it is a board-level threat for any business that relies on data. If you run a company with 10–200 staff somewhere between Leeds and London, this short guide is written for you: what ransomware-resistant backups actually are, why they matter, and how to adopt them without bankrupting the business or drowning in techno-babble.

Why your backups must be ransomware-resistant

Traditional backups are often part of the same network they’re supposed to protect. That’s convenient — until malware finds its way in and deletes or encrypts those backups along with the live systems. The result is not just lost files: it’s lost time, frustrated customers, interrupted invoices and a very awkward conversation with your regulator or insurer.

For UK businesses the consequences are practical: weeks of downtime for operations such as payroll or order processing; reputational damage when invoices or delivery estimates slip; and possible questions from the ICO if personal data is affected. In short, backups that can be tampered with are not a safety net — they’re false comfort.

What we mean by “ransomware-resistant backups” (in plain English)

Ransomware-resistant backups are copies of your data that an attacker cannot easily alter, encrypt or delete. That doesn’t mean they’re magical — it means they’re set up so that when something bad happens you can restore business operations quickly and without paying a ransom.

Key traits to expect, explained simply:

  • Isolated copies: At least one backup copy sits where ransomware can’t reach it — physically or logically separated from the main systems.
  • Immutable or write-once: Backups that can’t be changed after they’re written. Think of them as digital snapshots you can’t go back and overwrite.
  • Versioning and retention: Multiple historical copies so you can roll back to a point before the attack.
  • Tested restores: Backups are only useful if you can restore them — regularly testing that process is essential.

How to build ransomware-resistant backups without overpaying

You don’t need to be a tech giant to get this right. Focus on outcomes: quick recovery, minimal data loss, predictable cost. Here’s a practical route many UK SMEs take.

1. Know what matters

Make a short list of systems that would stop the business cold if they went offline — accounts, CRM, order systems, payroll. Prioritise those for faster recovery. I’ve sat in more than a few emergency meetings where we realised the invoicing system was the real linchpin.

2. Separate at least one copy

Keep a copy that’s not accessible from the main network. This can be a cloud copy with immutability enabled, a physically offline disk stored securely, or a service that keeps a segregated copy. If you’re unsure what’s right, start simple: an offsite copy that can’t be reached by the same credentials used for day-to-day systems.

For more practical guidance on planning and costs for backups, see a straightforward resource on data backup for your business that walks through options for small and mid-sized firms.

3. Use immutable snapshots where possible

Many cloud providers and modern backup solutions offer immutable snapshots — once written they can’t be altered for a set period. That prevents attackers from scrubbing your history. This isn’t an expensive premium feature any more; several solutions aimed at SMEs include it, and it’s worth budgeting for.

4. Encrypt and control access

Backups should be encrypted and tightly controlled. If your backup credentials are the same as your regular admin accounts, you’ve lost half the point. Separate accounts, strong passwords and MFA for backup access are straightforward, practical steps.

5. Test the restores

Run restore drills. I recommend a light-touch restore exercise every quarter and a full restore once a year. The more realistic the drill, the better you’ll know how long a real recovery will take.

Costs, procurement and who to involve

Budgeting for ransomware-resistant backups is less about buying shiny kit and more about buying predictability. Consider the cost of an afternoon (or a week) of downtime: lost staff hours, delayed invoices, and the hit to trusted relationships. Often, spending on backup resilience is cheaper than the first week of disruption.

Who should be involved? A small steering group that includes someone who understands the systems (IT or a trusted adviser), someone who understands the business impact (operations or finance), and someone who will own the process day-to-day.

Practical checklist to get started

  • Identify critical systems and data.
  • Make at least one copy outside the main network.
  • Enable immutability or write-once retention where possible.
  • Use separate credentials and MFA for backup access.
  • Encrypt backups in transit and at rest.
  • Run restore tests quarterly; document the process.
  • Review insurance and regulatory obligations (GDPR/ICO) and ensure backups support those requirements.

FAQ

Are backups immune to ransomware?

No. Backups aren’t automatically immune — they can be corrupted or deleted if they’re accessible to the same attackers. That’s why you need at least one copy that’s isolated or immutable so attackers can’t touch it.

How often should backups be tested?

Test them regularly. A light restore drill every quarter and a more comprehensive restore at least once a year is a sensible starting point. Tests should verify both the data and the process — who does what, and how long it takes.

Can cloud backups stop ransomware?

Cloud backups can be very effective if they’re configured correctly — particularly if the provider offers immutability and segregated storage. The cloud is not a cure-all; it must be part of a wider plan that includes access controls and testing.

What about backup costs for a small budget?

Think of resilience as insurance. Backups can be scaled to your needs: protect the most critical systems first, and expand coverage as you grow. Often the cheapest option is the one that lets you recover fast enough to keep trading.

Do I need to tell customers or regulators if a backup is affected?

If personal data is compromised you must consider your regulatory obligations under GDPR and speak to your insurer and legal adviser. Even if the backup itself is intact, transparency with affected customers about recovery times helps maintain trust.

Ransomware-resistant backups are not a one-off project: they’re an operating choice that reduces downtime, protects revenue and shields reputation. Start small, focus on the most important systems, and prove your restores before you need them. Do that and you’ll save time, avoid unnecessary costs and sleep a lot easier — which, in my experience working with firms across the UK, is money well spent.

If you want to turn this into action, schedule a short review to confirm your critical systems and a realistic recovery plan — the outcomes are straightforward: less downtime, lower risk of unexpected costs, and more credibility with customers and regulators.