Is the ISA 62443 Standard Right for You?

The manufacturing and critical infrastructure sectors face a unique cybersecurity challenge: securing operational technology (OT) and industrial control systems (ICS) that were historically designed for reliability and safety, not for connectivity or cyber resilience.

These systems (including programmable logic controllers (PLCs), distributed control systems (DCS), and supervisory control and data acquisition (SCADA) platforms) are increasingly integrated with enterprise IT networks and even the cloud. As a result, the attack surface is expanding, and the consequences of a breach can include not only data loss, but also physical disruption, equipment damage, or even safety incidents.

To help organizations meet these challenges, the ISA 62443 series provides a globally recognized, sector-agnostic framework for securing Industrial Automation and Control Systems (IACS). Developed collaboratively by the International Society of Automation (ISA) and adopted by the International Electrotechnical Commission (IEC), the 62443 standards offer a comprehensive, lifecycle-based approach to securing industrial environments.

In this post, we’ll explore:

The background and structure of the ISA/IEC 62443 family of standards
The key components and concepts organizations need to understand
The benefits and implementation challenges
And most importantly, practical next steps for organizations looking to get started

Background on the ISA 62443 Standards

The 62443 standards were developed by the International Society of Automation (ISA) to strengthen the safety, availability, integrity, and confidentiality of IACS. First introduced in 2007, the 62443 series builds upon earlier foundational standards such as ISA-99 and ISA-95, integrating decades of insight into how industrial systems operate and how they must be secured.

What sets ISA 62443 apart is its collaborative, consensus-based development. Drawing on input from industry experts, technology vendors, control system engineers, and cybersecurity professionals across multiple sectors, the standards reflect real-world operational challenges and priorities.

ISA 62443 is sector-agnostic and globally applicable, making it suitable for use in:

Critical infrastructure (e.g., power, water, and transportation)
Discrete and process manufacturing
Oil & gas, chemicals, and other high-risk industrial sectors

As a result, many countries have formally adopted or aligned national cybersecurity regulations and guidance with ISA 62443, recognizing it as a best-practice foundation for securing IACS environments.

Overview of the ISA 62443 Standards

The ISA 62443 series consists of a comprehensive set of standards that address cybersecurity across the entire lifecycle of IACS—from system design and development through deployment, maintenance, and eventual decommissioning.

The framework is divided into four key categories, each covering distinct domains of responsibility. These categories are further broken down into multiple parts, providing both conceptual guidance and technical requirements for securing IACS environments.

The Four Main Sections of ISA 62443 are:

62443-1: General Topics
Introduces foundational concepts, terminology, and methodologies used throughout the series. It serves as the common language for all stakeholders working with the standards.
62443-2: Policies and Procedures
Focuses on the development and implementation of a comprehensive cybersecurity management system (CSMS). It addresses governance, risk management, asset inventory, and operational policies.
62443-3: System Requirements
Provides technical system requirements, including conducting risk assessments, defining system zones and conduits, and selecting appropriate security controls.
62443-4: Component Requirements
Targets product suppliers and vendors, focusing on secure product development practices (SDLC)and technical security capabilities at the component level (e.g., PLCs, HMIs, switches).

The ISA 62443 family currently includes 14 interrelated documents, each designed to support collaboration across multiple roles throughout the IACS ecosystem, including asset owners, system integrators, and product suppliers. An overview of all fourteen parts of the standard is shown below..

One of the defining features of the ISA 62443 standards is their role-specific approach. They clearly outline security responsibilities based on the role an individual or organization plays in the lifecycle of an IACS.This clarity helps ensure accountability, reduces gaps, and aligns technical and organizational activities across complex environments. These key roles include:

Product Suppliers
Develop, manufacture, and support the hardware and software components used in industrial control systems. They are responsible for embedding security into their products through secure development lifecycle practices.
Asset Owners
Operate and manage the IACS. These organizations bear responsibility for cybersecurity governance, risk management, and ongoing operational resilience of their industrial environments.
Integration Service Providers
Design, install, configure, and commission IACS. They play a critical role in system architecture, segmentation, secure configuration, and ensuring compliance with defined security levels.
Maintenance Service Providers
Support the ongoing operation, patching, and troubleshooting of the IACS on behalf of Asset Owners. Their work is essential to maintaining system security throughout the operational phase.

It’s important to note that a single organization may fulfill multiple roles within a project or over the lifespan of a system. For example:

An Asset Owner might also act as their own Maintenance Provider
A Product Supplier may also serve as an Integration Provider for their technology stack

The ISA 62443 model accounts for these real-world overlaps by allowing organizations to apply role-based requirements flexibly and appropriately, depending on their responsibilities in a given context.

So How Do You Use the ISA-62443 Standards?

In this blog post, we’ll explore how Asset Owners can apply the ISA 62443 standards to strengthen their OT/ICS cybersecurity programs. Our focus will center on two foundational elements of the standard that are especially relevant for Asset Owners: security zones and conduits and risk assessments.

Security Zones and Conduits

A central tenet of the ISA 62443 standards is the use of network segmentation through security zones and conduits. This model supports a risk-informed, layered approach to protecting IACS.

Security Zones: Risk-Based Segmentation

Security zones are logical or physical groupings of assets that share similar cybersecurity requirements and risk profiles. These zones allow organizations to:

Tailor security controls based on the function and criticality of systems within each zone
Enforce least privilege and reduce lateral threat movement
Align with operational dependencies without sacrificing protection

Each zone is assigned an appropriate Security Level (SL), which determines the required countermeasures based on potential threats and the consequences of compromise.

Conduits: Controlled Communication Paths

Zones are interconnected via conduits, which serve as chokepoints for data flow between zones. These conduits are where organizations implement and enforce access control, traffic filtering, and monitoring.

Examples of conduit technologies include:

Firewalls
Data diodes
Demilitarized zones (DMZs)
Industrial protocol-aware gateways

For instance, a conduit between a Level 3 manufacturing operations zone and a Level 2 supervisory control zone might only allow unidirectional data flow, with strict enforcement to prevent backflow or unauthorized access.

Alignment with the Purdue Model

This zone-and-conduit approach closely aligns with the Purdue Enterprise Reference Architecture (PERA)—a model familiar to many in the industrial automation space. While ISA 62443 offers more granular risk-based guidance, it builds on the same foundational concept of tiered network segmentation.

By applying these principles, organizations can achieve:

Defense in depth
Containment of threats
Operational resilience, even if a single zone is compromised

For detailed guidance on defining zones and building secure architectures, refer to ISA-62443-1-1: Terminology, Concepts, and Models.

Risk Assessments

The ISA 62443-3-2 standard offers detailed guidance for conducting cybersecurity risk assessments within IACS. This process is central to designing appropriate security zones and conduits and selecting risk-informed countermeasures.

While the standard does not prescribe a specific risk assessment methodology, it does define expected outcomes and key activities. Asset Owners and Assessors are expected to adopt or develop a methodology that aligns with their organization’s structure, processes, and risk tolerance.

The ISA 62443-3-2 standard outlines seven key processes that support the creation of security zones and conduits, while systematically assessing cybersecurity risk.

The ZCR2 step identifies initial unmitigated risks and compares them to the organization’s tolerable risk thresholds. If any zone’s unmitigated risk exceeds this threshold, the standard calls for a more detailed cybersecurity risk assessment, which includes:

Identifying threats and known vulnerabilities
Estimating the consequences and likelihood of threat realization
Calculating the unmitigated risk to the system
Assessing existing security controls and determining the resulting residual risk
Selecting additional countermeasures if residual risk remains above tolerable levels

This cyclical process allows Asset Owners to systematically reduce risk by layering controls where they are needed most—without overburdening zones with unnecessary protections.

Benefits of Using the ISA 62443 Standards

Adopting the ISA 62443 standards offers meaningful advantages for industrial organizations seeking to build resilient, secure, and standards-aligned control environments. The main advantages include:

1. Structured Risk Management

ISA 62443 provides a systematic framework for identifying, assessing, and mitigating cybersecurity risks to IACS. Through defined SLs and role-specific requirements, it enables organizations to align security investments with actual operational risk

2. Defense-in-Depth Strategy

The standards support a layered, defense-in-depth approach which addresses cybersecurity at the policy, procedural, physical, and technical levels. This holistic coverage helps protect against both external threats and internal misconfigurations or process failures.

3. Lifecycle Approach

Unlike many frameworks that focus on point-in-time controls, ISA 62443 is designed to address security throughout the entire system lifecycle—from initial design and procurement to deployment, maintenance, and decommissioning.

4. Enhanced Safety & Availability

Effective implementation of ISA 62443 reduces the likelihood of unplanned downtime, improves system reliability, and helps protect human safety by minimizing the risk of cyber events that could impact critical processes or fail-safe mechanisms.

5. Regulatory Alignment and Compliance Enablement

The ISA 62443 framework maps closely to other standards and regulatory requirements, including NIST CSF, ISO/IEC 27001, and NERC CIP. It provides a flexible but structured path to meet cross-sector compliance goals—supporting organizations operating across multiple geographies or industries.

Challenges with Using the ISA 62443 Standards

While the ISA 62443 standards offer a robust, structured approach to securing industrial control systems, they also present real-world challenges—particularly for organizations with constrained budgets, legacy infrastructure, or limited cybersecurity maturity.

Here are six common obstacles organizations may encounter:

1. Cost

Unlike some frameworks that are freely distributed, ISA 62443 documents must be purchased individually, often at $230 or more per standard. While ISA members can view the standards online, they cannot download or share them. This poses coordination challenges, especially when working with third-party integrators, suppliers, or service providers who must each acquire their own copies to support your program.

2. Resource Demands

Achieving and maintaining high security assurance levels under ISA 62443 often requires a significant investment in people, processes, and technology. This includes skilled personnel, security-specific training, and tooling and architecture updates. These investments can be difficult for small and mid-sized organizations to absorb without executive sponsorship or a phased implementation strategy.

3. Legacy Systems Constraints

Many industrial environments still rely on aging or unsupported technologies that were never designed with cybersecurity in mind. Retrofitting these systems to meet 62443 requirements can be technically challenging, or in some cases not even feasible without full replacement.

4. Organizational Resistance

ISA 62443 often introduces new processes, controls, and collaboration between IT and OT teams. In organizations with deeply entrenched operational silos, this can lead to cultural pushback or skepticism about the value or practicality of new security expectations.

5. Organizational Inertia

The sheer scope and depth of the 62443 standards can feel overwhelming, particularly for organizations without prior experience in formalized cybersecurity frameworks. Without clear prioritization, many teams find themselves stalled at the starting line.

6. Vendor and Supply Chain Dependencies

Many 62443 requirements depend on the security posture of external vendors and integrators. If your product suppliers or service providers are not aligned with the standards, or are constrained by the cost and access barriers noted above, it can slow progress and limit what you can implement internally.

Next Steps for Adopting the ISA 62443 Standards

Despite the challenges, the ISA 62443 standards remain the most comprehensive and widely applicable framework for securing IACS. If you’re ready to improve your industrial cybersecurity posture, here are the recommended steps to begin your 62443 journey:

1. Secure Leadership Commitment

Strong cybersecurity programs don’t start in the control room, they start in the boardroom. Gaining support from executive leadership is critical to securing resources, driving cultural change, and embedding cybersecurity as a core business priority.

2. Get Operations Buy-in

The people who operate and maintain your IACS know those systems better than anyone. Their insight is essential for developing realistic risk assessments and ensuring that proposed controls do not interfere with reliability, safety, or performance.

3. Conduct an Initial Cybersecurity Risk Assessment

Start with a high-level assessment focused on identifying key vulnerabilities, threats, and potential consequences. This provides the foundation for prioritizing remediation efforts and establishing your security baseline.

4. Perform a Gap Analysis and Prioritize Remediation Efforts

Use the results of the assessment to identify where your current posture falls short of 62443 requirements, and prioritize high-impact, cost-effective controls that reduce the most risk with the least disruption.

5. Work with Experienced IACS Security Advisors

Implementing 62443 isn’t just about compliance, it’s about building a sustainable, secure-by-design OT environment. Partnering with seasoned experts can help you avoid common pitfalls, accelerate adoption, and align cybersecurity efforts with operational goals.

How Enaxy Can Help

At Enaxy, we’ve supported clients across energy, manufacturing, transportation, and critical infrastructure in applying ISA 62443 in both brownfield and greenfield environments. From assessments and remediation planning to technical control implementation, we help organizations secure operations without sacrificing uptime or safety.

Whether you’re just getting started or need guidance on scaling your program, our team is ready to assist.