Patch Management Strategies for OT/IT Environments — Keeping Manufacturers Secure Without Stopping the Line

For most businesses, patching is straightforward: push updates, reboot devices, done. But if you run a manufacturing facility in Northwest Arkansas, you already know it’s not that simple. Your environment has two very different worlds living under one roof — the IT side (desktops, servers, cloud apps) and the OT side (PLCs, SCADA systems, HMIs, industrial controllers). Keeping both secure with patches is one of the most challenging — and most important — things you can do for your operation.

The problem isn’t that manufacturers don’t want to patch. It’s that patching in an OT environment carries real production risk. An unplanned reboot of a PLC can stop a line. A firmware update that hasn’t been validated by the vendor can brick a machine. And many industrial systems run software that hasn’t been updated in years — not out of neglect, but because the vendor no longer supports it, or because the update process requires a full system validation.

This guide walks through a practical patch management strategy built for exactly this kind of dual IT/OT environment.

Why Patch Management Is More Complicated in Manufacturing

In a typical office environment, patching is mostly about cadence and automation. In a manufacturing environment, you’re dealing with:

• Legacy OT systems — SCADA and HMI software often runs on Windows XP or Windows 7 machines that can’t be updated without significant investment.
• Vendor lock-in — Many industrial systems can only be patched with vendor-approved updates, and vendors sometimes take months to test and release patches.
• Uptime requirements — A 24/7 production line doesn’t have natural maintenance windows, and unplanned downtime is expensive.
• Air-gapped or semi-isolated systems — OT networks that are intentionally separated from IT networks require a manual or indirect patching process.
• Mixed ownership — IT manages servers and workstations, but operations owns the plant floor equipment. That split creates coordination gaps.

Getting patch management right in this environment requires a strategy that accounts for all of these constraints — not just a policy that says “patch everything within 30 days.”

Step 1: Build a Complete Asset Inventory

You can’t patch what you don’t know about. The first step is building a full inventory of every device in both your IT and OT environments.

For IT assets, this is relatively easy — most RMM (remote monitoring and management) tools can auto-discover and inventory workstations, servers, and network devices.

For OT assets, it takes more effort. You’ll need to:

• Work with operations to document every PLC, HMI, SCADA workstation, and industrial controller on the plant floor
• Record the operating system, firmware version, software version, and vendor for each device
• Note whether the device is network-connected or air-gapped
• Identify the vendor’s patch/update policy for each system

This inventory becomes the foundation of your patching strategy. Without it, you’re operating blind.

Step 2: Segment IT and OT Networks

Before you can manage patches effectively, you need to make sure your IT and OT networks are properly segmented. Patches on the IT side shouldn’t be able to disrupt OT systems — and OT systems shouldn’t be reachable from the internet or from compromised IT endpoints.

If your plant floor equipment is on the same flat network as your office computers, a ransomware attack that gets in through a phishing email can reach your production systems directly. Network segmentation limits the blast radius.

Proper segmentation also gives you more control over how patches are deployed. You can push IT updates aggressively without worrying about touching OT systems, and you can plan OT patching as a separate, more deliberate process.

Step 3: Separate Patch Policies for IT and OT

One of the biggest mistakes manufacturers make is trying to apply a single patching policy to both IT and OT. These environments have fundamentally different risk profiles and update requirements.

IT Patching Policy

For your standard IT environment — workstations, servers, network gear — you should be patching aggressively. Microsoft releases patches on the second Tuesday of every month (Patch Tuesday), and critical vulnerabilities get emergency out-of-band patches as needed.

A reasonable IT patch policy for manufacturers:

Use an RMM tool to automate deployment, track compliance, and generate reports. Automate reboots during off-hours whenever possible.

OT Patching Policy

OT patching has to be more deliberate. The process typically looks like this:

1. Monitor vendor advisories — Subscribe to patch notifications from every OT vendor in your environment (Rockwell Automation, Siemens, Honeywell, etc.)
2. Assess impact before acting — When a patch is released, determine whether it applies to your specific hardware and firmware version
3. Check vendor approval — For many industrial systems, you should only install patches that have been tested and approved by the OT vendor
4. Test in a non-production environment — If possible, test patches on a spare or lab system before applying to production
5. Schedule planned maintenance windows — Coordinate with operations to schedule patching during planned downtime (shift changes, scheduled maintenance, weekends)
6. Document everything — Keep a record of what was patched, when, by whom, and the current patch status of every OT device

For truly legacy OT systems that cannot be patched, compensating controls become critical: network isolation, application whitelisting, enhanced monitoring, and physical security.

Step 4: Prioritize Vulnerabilities by Risk, Not Just CVSS Score

The Common Vulnerability Scoring System (CVSS) is a useful starting point, but it doesn’t tell the whole story for manufacturers. A high-CVSS vulnerability in an air-gapped PLC that has no network exposure is less urgent than a medium-CVSS vulnerability in a workstation that’s directly internet-accessible.

When prioritizing what to patch first, consider:

• Exposure — Is the vulnerable system reachable from the internet? From other network segments?
• Exploitability — Is there active exploitation of this vulnerability in the wild?
• Impact — What happens if this system is compromised? Does it affect production? Safety? Data?
• Asset criticality — Is this a core production system, or a non-critical workstation?

Vendors like CISA publish Known Exploited Vulnerabilities (KEV) lists that are particularly useful — if a vulnerability is on that list, it’s being actively exploited and should be treated as urgent regardless of CVSS score.

Step 5: Handle Legacy and End-of-Life Systems

This is where many NWA manufacturers get stuck. You have a SCADA workstation running Windows 7. The OT vendor hasn’t released an update in four years. The vendor’s support contract has expired. What do you do?

Option 1: Isolate and compensate Segment the legacy system onto its own isolated network segment with no inbound connections from IT or the internet. Implement application whitelisting so only known-good software can run. Monitor traffic closely. This doesn’t fix the vulnerability, but it significantly limits exposure.

Option 2: Upgrade the OS or system Work with the OT vendor to determine whether the system can be migrated to a supported OS. This often requires a system validation and may involve downtime, but it’s the right long-term answer.

Option 3: Replace the system If the hardware is aging alongside the software, it may be time to replace the system entirely. Factor in the total cost of compensating controls versus the cost of a modern replacement.

There’s no universal right answer — it depends on your specific equipment, vendor relationships, budget, and risk tolerance. But ignoring the problem isn’t an option.

Step 6: Assign Ownership and Accountability

Patch management fails when no one owns it. In a manufacturing environment, this is particularly common because IT and operations may both assume the other team is handling things.

Define clear ownership:

• IT team owns patching for all IT assets: workstations, servers, network gear, cloud systems
• Operations or engineering owns awareness and scheduling for OT assets
• IT team supports OT patching coordination, monitoring, and documentation
• Leadership receives regular reporting on patch compliance status

Put this in writing and make it part of your IT policy documentation. If you’re working with a managed IT provider, make sure their contract explicitly covers patch management and defines SLAs for patch deployment.

Step 7: Report and Improve

Patch management isn’t a set-it-and-forget-it process. You need regular reporting to understand your current exposure and identify gaps.

Useful metrics to track:

• Patch compliance rate — What percentage of IT assets are fully patched?
• Mean time to patch — How long does it take from patch release to deployment?
• Vulnerability age — How many open vulnerabilities are older than 30/60/90 days?
• OT patch status — Current firmware/software versions for all OT devices vs. latest available

Review these metrics monthly at minimum, and use them to continuously improve your process. If you’re consistently missing your patch windows, that’s a signal to invest in better tooling or staffing.

Bringing It Together

Patch management in a manufacturing environment isn’t simple, but it is manageable with the right approach. The key principles are:

1. Know what you have — complete asset inventory for both IT and OT
2. Segment your networks so problems stay contained
3. Apply different policies for IT and OT based on their different risk profiles
4. Prioritize by real-world risk, not just severity scores
5. Have a plan for legacy systems that can’t be patched
6. Assign clear ownership so nothing falls through the cracks
7. Measure and improve continuously

For NWA manufacturers operating in competitive industries — aerospace, food production, defense supply chains — a breach or ransomware attack that takes production offline isn’t just a cybersecurity problem. It’s an operational and business continuity problem that can cost far more than the investment in a solid patch management program.

Ready to build a patch management strategy that actually fits your manufacturing environment? Get in touch.