IoT Security in Manufacturing: Key Risks & Solutions

Connected devices on the factory floor are generating real operational value: real-time throughput data, predictive maintenance signals, energy consumption insights. IoT Analytics reports that there will be 21.1 billion connected IoT devices globally by the end of 2025, growing 14% year-on-year, with manufacturing among the most active adopters. 

The Industrial Internet of Things (IIoT) connects modern manufacturing across the entire supply chain. Sensors on conveyor lines, programmable logic controllers (PLCs) managing process flows, condition-monitoring devices on critical assets, all feeding data that operations teams can use to make better decisions, faster.

Industrial IoT security has to keep pace with that ambition.

This guide covers where structural risks lie in the manufacturing industry and how controlled data flow at the IT/OT boundary enables companies to capture IIoT value without compromising operational integrity.

Industrial IoT isn’t simply enterprise IoT deployed in a factory setting. IIoT refers to sensors, actuators, PLCs, human-machine interfaces (HMIs), and connected machines operating within operational technology (OT) environments, where the primary function is to control physical processes rather than process information.

That distinction changes the security calculus entirely. A misconfigured enterprise laptop causes a data headache. A compromised PLC on a chemical dosing line can trigger a safety incident, destroy a production batch, or prompt a regulatory investigation. The operational consequences can be potentially dangerous.

You also can’t apply standard IT remediation to IIoT devices. You can’t push a patch to a temperature sensor mid-production run. You can’t reboot a conveyor controller at 2 am without coordinating a planned outage. The normal security measures simply don’t translate.

Connected devices in manufacturing are hard to secure because they were designed for reliability and longevity in industrial environments, not for the threat model that comes with network connectivity. Here’s what that looks like:

Many industrial devices ship with default usernames and passwords that are published in vendor documentation and widely known across the industry. Changing them isn’t always straightforward, and in some cases the credentials are hardcoded in the firmware. This is a design limitation with no simple fix.

Endpoint detection and response tools, monitoring agents, antivirus software – these all require compute headroom that most industrial devices simply don’t have. A sensor or actuator running a minimal embedded OS has no capacity to run additional security software. That means no local visibility, no behavioural monitoring, and no alerts when something goes wrong at the device level.

Unpatched firmware is responsible for approximately 60% of IoT security breaches. Many IIoT device manufacturers release firmware updates infrequently, and applying those updates in an operational environment requires scheduled downtime. The result is devices running known-vulnerable firmware for months or years after patches become available.

Enterprise IT hardware is typically refreshed on a 3- to 5-year cycle. IIoT devices on the factory floor routinely run for 10 to 25 years. That means devices deployed before modern cybersecurity standards were written are still actively controlling production processes today.

A typical manufacturing facility might have industrial IoT devices from dozens of different vendors, each with its own firmware update process, authentication model, and communication protocol. Enforcing a consistent security policy across that mix is genuinely difficult. There’s no common baseline.

Every IIoT device added to your OT network is a potential entry point. More connected endpoints mean more opportunities for an attacker to find a misconfigured device, an unpatched software weakness, or a default credential that was never changed.

What makes the risk particularly acute for manufacturing companies is lateral movement. A compromised temperature sensor or conveyor controller doesn’t just represent a problem at that device. It represents a foothold within your OT network, from which an attacker can probe for higher-value targets such as SCADA systems, industrial control systems (ICS), or the IT network beyond.

When you combine that with flat OT network architectures where devices sit alongside production control systems, the path from a low-value sensor to a high-consequence system can be very short.

The regulatory picture has sharpened considerably, and the deadlines are closer than many manufacturers realise.

The EU Cyber Resilience Act (CRA) introduces a requirement, effective from September 2026, for manufacturers to report actively exploited vulnerabilities within 24 hours. That’s a tight window, and it demands visibility into your IIoT estate that many organisations don’t currently have. If you can’t see your devices, you can’t report on them.

IEC 62443, the international standard for industrial automation and control system security, applies directly to IIoT deployments. It sets security requirements across zones and conduits, and provides the architecture model that most serious OT security programmes are built around.

Compliance here is best treated as a prompt to act. Organisations that invest now in asset visibility, network segmentation, and controlled data transfer will be better placed for September 2026, and they’ll have better operational security in the meantime.

Network segmentation means dividing your OT network into isolated zones so that a compromised device in one zone can’t directly reach production control systems or IT networks.

In practice, this means placing connected devices into dedicated network segments, enforcing strict access controls between zones, and ensuring that communication between zones passes through inspection points rather than flowing freely. The Purdue Model and ISA/IEC 62443 zone hierarchy both provide well-established architecture patterns for doing this in manufacturing environments.

Segmentation limits lateral movement, which is why it’s considered a best practice. If an attacker compromises a device in your sensor network, they’re contained within that zone. They can’t reach your SCADA systems or your IT analytics platform without crossing a controlled boundary.

Industry stakeholders need OT data to flow into IT analytics platforms for efficiency monitoring, predictive maintenance, and energy management. The answer isn’t to block that flow. It’s to control it.

Controlled, monitored data transfer means only authorised, inspected data crosses the IT/OT boundary, and the direction of flow is enforced by design rather than policy alone. Policy can be misconfigured. Design is harder to circumvent.

For example, 4Secure’s approach to IT/OT secure connection uses data diodes and TrustedFilter® to enforce exactly this. A data diode allows data to move in one direction only; there is no network path that permits return traffic. TrustedFilter® adds content-level inspection, ensuring that what crosses the boundary is what you intended, not something that’s been modified or injected in transit.

The result is that your IIoT data reaches your analytics platforms, your production visibility improves, and your OT environment isn’t reachable from the IT side. That’s the architecture that makes the smart factory genuinely safe to operate.

Most manufacturers aren’t starting from scratch. You’ve got legacy IIoT devices already in place, a mix of vendors, and production schedules that don’t leave much room for infrastructure changes. That’s the reality, and it’s workable.

A practical starting sequence:

• Asset discovery: Build a complete inventory of every IIoT device on your OT network. You can’t protect what you can’t see, and you can’t report on what you haven’t catalogued.
• Credential audit: Identify devices still running default or shared credentials and prioritise remediation where possible.
• Firmware version review: Map your device firmware versions against known vulnerabilities and vendor patch availability.
• Segmentation assessment: Identify where your OT network is flat and where IIoT devices have direct paths to production control systems or IT networks.
• Boundary monitoring: Instrument your IT/OT boundary so you have visibility into what data is crossing, in which direction, and whether it matches your authorised flows.

Explore 4Secure’s IT/OT Secure Connection capability to see how this is implemented in live manufacturing environments. Explore TrustedFilter®