OT/ICS security refers to protecting the operational technology and industrial control systems that physically run manufacturing equipment, from programmable logic controllers (PLCs) on the production line to the SCADA systems that monitor and control entire plants. Manufacturing firms can no longer treat this as separate from standard IT security because OT and IT networks are now deeply connected, and an attack that starts on a standard IT system, such as a phishing email, can now reach the equipment that physically runs your factory floor.
For decades, the systems running manufacturing equipment — PLCs, SCADA, and industrial sensors — were physically isolated from corporate IT networks and the internet entirely. This isolation, often called an "air gap," was the primary security control, and for a long time it worked well enough that dedicated OT security was barely discussed outside specialist circles.
That isolation has largely disappeared. Modern manufacturing relies on connected sensors for predictive maintenance, remote monitoring for multi-site operations, and IT systems that now touch production data directly for efficiency and reporting. The convergence of IT and OT networks, while genuinely valuable for operations, has removed the protection that air-gapped isolation used to provide, and most manufacturing security programmes have not caught up to that shift.
Here is what makes OT/ICS security genuinely different from IT security, why manufacturing has become a primary target, and the practical first steps to close the gap.
What Makes OT/ICS Security Different from IT Security?
This is the gap that catches most manufacturing organisations off guard: standard IT security practices, applied directly to OT environments, often do not work and can actively cause harm.
Availability matters more than confidentiality: In IT security, protecting data confidentiality is usually the top priority. In OT environments, keeping production running safely is the top priority. A security control that takes a system offline to patch a vulnerability — standard practice in IT — can halt an entire production line and, in some industries, create physical safety risks.
Patching is far slower and riskier: IT systems are typically patched on a regular cycle. OT systems often run on legacy operating systems that cannot be easily patched without risking equipment malfunction, voiding vendor warranties, or requiring a full production shutdown to test safely. Some industrial equipment runs on systems that have not been updated in over a decade, by design, because the equipment itself has a 20 to 30 year operational lifespan.
The consequences of failure are physical, not just digital: A compromised IT system typically results in data loss or downtime. A compromised OT system can result in equipment damage, production line malfunction, or in worst cases, genuine physical safety incidents for plant employees.
Visibility is typically much lower: Many manufacturing organisations have detailed asset inventories for their IT environment and very little visibility into what industrial devices actually exist on their OT network, what firmware they run, or how they are configured, simply because OT environments were never built with IT-style asset management in mind.
Digisecuritas' OT and IoT Security practice is built specifically around these differences, applying security controls designed for industrial environments rather than forcing standard IT security tooling onto systems it was never designed to protect.
Why Manufacturing Has Become a Primary Target?
Ransomware groups have learned that manufacturing pays: A ransomware attack that halts a production line costs an organisation revenue immediately, every hour the line is down, which creates strong pressure to pay quickly. Attackers have specifically noted this dynamic, and manufacturing has consistently ranked among the most targeted industries for ransomware in recent years.
IT/OT convergence has expanded the attack surface: As manufacturing connects OT systems to IT networks for efficiency, an attacker who compromises a standard IT system — often through phishing or a vulnerable internet-facing service — gains a potential path into the OT environment that simply did not exist when the two networks were fully separated.
Legacy systems create persistent vulnerability: Industrial control systems often run for decades without meaningful security updates, meaning known vulnerabilities, sometimes documented publicly for years, remain exploitable indefinitely on equipment that cannot be easily patched or replaced.
Supply chain pressure adds urgency to pay quickly: Manufacturing organisations are frequently part of larger supply chains where a production halt does not just affect their own revenue. It affects every downstream customer depending on their output, which increases pressure to resolve an incident as fast as possible, often by paying a ransom rather than recovering methodically.
Common OT/ICS Security Risks in Manufacturing
- Unsegmented networks: Without proper network segmentation between IT and OT environments, an attacker who compromises a standard office workstation can move laterally into the systems controlling production equipment with minimal additional effort.
- Default and shared credentials: Many industrial devices ship with default credentials that are never changed, or use shared credentials across multiple systems for operational convenience, both of which significantly reduce the effort required for an attacker to gain control.
- Unmonitored remote access: Vendor and contractor remote access to OT systems, often set up years ago for maintenance convenience, is frequently left active and unmonitored long after it is actually needed, creating a persistent, often forgotten entry point.
- Lack of OT-specific monitoring: Standard IT security monitoring tools are often not deployed in OT environments at all, or are deployed without the specialised understanding of industrial protocols needed to detect genuinely malicious activity versus normal operational behaviour.
- Outdated or unsupported systems: Equipment running operating systems that are no longer supported by the vendor, common throughout manufacturing given long equipment lifespans, cannot receive security patches even when critical vulnerabilities are identified.
Practical First Steps for Manufacturing Organisations
Build an accurate OT asset inventory. You cannot protect systems you do not know exist. A thorough inventory of every PLC, sensor, SCADA component, and industrial device on the network, including firmware versions and connectivity, is the essential first step before anything else is possible.
Establish proper network segmentation. Implementing clear, enforced boundaries between IT and OT networks, following a structured model such as the widely used Purdue Model for industrial network architecture, limits how far an attacker who compromises one environment can move into the other.
Audit and eliminate unnecessary remote access. Review every remote access path into the OT environment, confirm which are genuinely still needed, and remove or tightly restrict the rest, with monitoring on whatever remains.
Deploy OT-aware monitoring. Standard network monitoring tools often misinterpret normal industrial protocol traffic. OT-specific monitoring solutions, built to understand protocols such as Modbus and DNP3, can distinguish genuine anomalies from routine operational activity far more accurately.
Develop an OT-specific incident response plan. A standard IT incident response plan, which may assume systems can be shut down immediately for containment, does not translate directly to an OT environment where shutting down a system carelessly can itself create a safety risk. OT incident response needs its own playbook, developed alongside plant operations and safety teams, not bolted onto an existing IT plan.
Digisecuritas' Cyber Incident Response Management service builds incident response capability that accounts for the operational and safety constraints unique to industrial environments, rather than applying a generic IT playbook to a production floor.
How OT Security Fits into a Broader Security Programme?
OT/ICS security should not exist as an isolated initiative disconnected from the rest of an organisation's security programme. The same governance discipline applied to IT security — risk assessment, access management, and continuous monitoring — needs to extend into the OT environment, adapted to its constraints rather than ignored because it is harder to apply.
This also extends to vendor risk. Many OT environments depend heavily on equipment vendors and integrators with their own remote access and maintenance responsibilities, which means the third-party risk management discipline that applies to software vendors applies just as directly to the OT equipment vendors and system integrators manufacturing organisations rely on.
Manufacturing organisations that have already invested in penetration testing for their IT environment should be aware that OT environments require a fundamentally different testing approach, given the physical safety risks of standard exploitation techniques applied to live production equipment. Specialised OT penetration testing, conducted with appropriate safety controls and often in coordination with plant operations, is a distinct discipline from the standard penetration testing most IT environments undergo.
Final Thoughts
The air gap that once protected manufacturing's industrial systems is gone in practice, even where organisations have not formally acknowledged that shift in their security planning. IT and OT convergence has created real operational value, and it has just as genuinely expanded the attack surface that ransomware groups and other threat actors are actively exploiting.
The manufacturing organisations managing this well are not the ones avoiding connectivity between IT and OT. They are the ones that have built visibility, segmentation, and monitoring specifically designed for industrial environments, rather than assuming standard IT security practices automatically transfer.
Digisecuritas helps manufacturing organisations assess OT/ICS security gaps and build protection designed for industrial environments, not generic IT security applied where it does not fit.
Book a Discovery Call to find out where your operational technology security actually stands.
Frequently Asked Questions
What is the difference between OT and ICS?
Operational Technology (OT) is the broader category covering all hardware and software that monitors or controls physical equipment and processes. Industrial Control Systems (ICS) is a specific subset of OT, including SCADA systems and PLCs, that directly control industrial processes such as manufacturing equipment or utility infrastructure.
Why can't OT systems just be patched like IT systems?
Many OT systems run on legacy operating systems that vendors no longer support, and patching can risk equipment malfunction, void warranties, or require a full production shutdown to test safely. Patching decisions in OT environments require coordination with equipment vendors and plant operations in a way standard IT patching typically does not.
Is full IT and OT network separation still realistic in 2026?
For most modern manufacturing operations, full separation is no longer practical given the operational value of connected sensors and remote monitoring. The more realistic and effective approach is proper network segmentation, which allows controlled, monitored connectivity between IT and OT rather than either full isolation or unrestricted access.
How is OT penetration testing different from standard IT penetration testing?
OT penetration testing must account for the physical safety risks of testing live industrial equipment, since standard exploitation techniques that are safe on IT systems can cause equipment damage or safety incidents in an OT environment. It requires specialised expertise, careful scoping, and close coordination with plant operations teams.
What is the Purdue Model and why does it matter for OT security?
The Purdue Model is a widely used reference architecture for segmenting industrial networks into distinct levels, separating business IT systems from control systems and physical process equipment. It provides a structured framework for implementing network segmentation in OT environments, which is one of the most effective controls against lateral movement from a compromised IT system into OT.