Introduction
If you run a manufacturing operation as a Tier 2 or Tier 3 supplier, cyber security might feel like a problem for bigger businesses. You’re not a bank. You don’t hold customer data. You don’t have a dedicated IT team. So why should you be worried about OT security in the supply chain?
The answer matters more than many smaller manufacturers realise. A cyber incident that takes your factory offline doesn’t just affect you. It stops you fulfilling orders, which can stop your customers fulfilling theirs. In a tightly sequenced supply chain, that kind of disruption travels fast and gets remembered. Being known as the business that caused a production stoppage is a serious commercial and reputational risk, even if the incident itself was outside your control.
There’s also a second pressure building quietly in the background. Larger customers are increasingly asking their suppliers about security posture. Some are already including it in contract renewals and procurement decisions. The ability to demonstrate credible, proportionate security controls is becoming part of what it means to be a reliable supplier, not just a nice-to-have.
The good news is that getting the basics right doesn’t require a large budget or a specialist team. It requires clarity on where you stand and a sensible starting point.
Why OT security feels overwhelming, and why it doesn’t have to be
Most smaller manufacturers haven’t ignored OT security out of carelessness. They’ve ignored it because it feels complicated, expensive, and hard to know where to start. Those are the three barriers we see most consistently when working with suppliers.
The first barrier is understanding. OT security isn’t the same as general cyber security, and advice aimed at office-based IT environments often doesn’t apply to factory floors.
The second is cost. The assumption is that OT security means bringing in a large consultancy and spending money the business doesn’t have.
The third is direction. Even when a business wants to act, it’s not always clear what to do first.
Each of these barriers is solvable. But it helps to start with what OT security actually is.
The difference between IT security and OT security
IT security protects the systems that handle your data, your emails, your finance software, and your business operations. OT security protects the systems that run your physical processes: the PLCs, SCADA systems, sensors, and industrial control equipment that keep your production lines moving.
These environments have different risk profiles. IT systems are updated regularly and can usually be patched or replaced without stopping work. OT systems are often older, sometimes running software that hasn’t been updated in years, and can’t simply be taken offline for maintenance without stopping production. Many were designed before cyber security was considered a priority.
This is why applying a standard IT security approach to an OT environment often misses the point. The tools, the vulnerabilities, and the priorities are different. A firewall policy that works for a server room doesn’t automatically protect a production line.
The basics that matter most
You don’t need to solve everything at once. For most smaller manufacturers, four areas form the foundation of a credible OT security posture.
Asset visibility
You can’t protect what you can’t see. Many manufacturers don’t have a clear picture of every device connected to their OT environment: the machines, the sensors, the legacy control systems, even the laptops used to configure equipment. Building that picture is the starting point for everything else.
Access controls
Who can access your OT systems, and how? Remote access in particular is a common vulnerability. If engineers, contractors, or third-party vendors can connect to your systems without strong authentication controls in place, that’s a risk that needs addressing early.
Network segmentation
In many older industrial environments, OT and IT systems share the same network or have poorly defined boundaries between them. Separating them, or at least ensuring there are clear controls at the boundary, limits how far a problem can spread if something goes wrong.
Patching and vulnerability management
OT systems often can’t be patched on the same schedule as IT systems, but that doesn’t mean the question can be ignored. Understanding which of your systems have known vulnerabilities, and having a plan for managing them within your operational constraints, is a basic but important discipline.
A simple way to think about priorities
A useful reference point here is the NIST Cybersecurity Framework, which structures security activity around five functions: Identify, Protect, Detect, Respond, and Recover. You don’t need to implement it formally, but it provides a sensible order of operations.
For a smaller manufacturer starting from scratch, Identify comes first. Before you can protect anything, you need to know what you have, what it does, and what would happen if it went offline. Protect comes second: once you know your assets, you can make proportionate decisions about access controls, segmentation, and basic hardening. Detect, Respond, and Recover become relevant as your posture matures.
The framework isn’t a checklist. It’s a way of thinking about where you are and what should come next.
What a proportionate starting point looks like
A smaller manufacturer doesn’t need to reach the same security maturity as a large enterprise. What’s needed is a credible, proportionate posture that reflects the actual risks of your environment and demonstrates that you take the issue seriously.
In practice, that means starting with a risk assessment. Not a lengthy audit that disrupts operations, but a structured review of your OT environment that gives you a clear picture of your assets, your vulnerabilities, and where to focus first. The output isn’t a pass or fail verdict. It’s a prioritised action plan that fits your budget and your operational reality.
A risk assessment also gives you something concrete to point to when customers ask about your security posture. That’s increasingly valuable. Being able to say “we’ve assessed our environment and here’s what we’re doing about it” is a more credible position than having no answer at all.
The cost of doing nothing
Smaller manufacturers sometimes weigh up the cost of improving their OT security against the probability of an incident and decide the risk is acceptable. That calculation is worth revisiting.
The cost of a cyber incident that takes your production offline isn’t just the recovery cost. It’s the orders you can’t fulfil, the contractual penalties you may face, the relationships you have to rebuild, and the reputation you carry into the next procurement conversation. And as customer expectations around supplier security continue to rise, a business that can’t demonstrate basic controls will find itself at a disadvantage even when nothing has gone wrong.
Getting the basics right isn’t about achieving perfection. It’s about reaching a position where you’re protected against the most likely risks, and where you can demonstrate that credibly to the customers who matter.
Where to start
If you’re a smaller manufacturer looking to understand your OT security position, the right starting point is a structured assessment of your environment. Harpoon works with manufacturers of all sizes, and our approach is designed to be proportionate, practical, and grounded in real operational environments.
- Find out how a Harpoon OT security assessment works
- Read our guide to supply chain cyber security for manufacturers
