How do you comply with IEC 62443?
- Cyber Instincts AB
- 26 nov.
- 3 min läsning
An Easy-to-Read Guide to the Industry’s Most Important Security Standard
IEC 62443 has quickly become the most established standard for protecting industrial automation and control systems. It is used across manufacturing, energy, logistics, process industries, and water treatment. But what does it actually mean to “work according to IEC 62443”?
This guide is written to make the topic less intimidating and to show how the standard can be followed without getting stuck in long documents or technical details.
What is IEC 62443 – in practice?
IEC 62443 consists of several parts that together describe how to build security in OT environments. A simple way to understand it is to see it through three perspectives:
The organization – how responsibility, processes, and governance should be structured.
The systems – how environments should be segmented, protected, and controlled.
The components – the requirements placed on technology, equipment, and software.
The strength of the standard is that it accounts for the realities of production, where operations must run 24/7 and where downtime is not acceptable.
How do you get started?
Here is the most essential and practical part: how you actually begin working according to IEC 62443.
1. Start with zones and conduits – the heart of IEC 62443
The first (and most important) step is to divide the OT environment into zones (areas with similar function and risk) and conduits (communication paths between zones).
This provides a clear picture of where protection is most needed.
Examples:
A robot cell can be a zone
A SCADA network another
Remote access its own area
Once the map exists, it becomes easier to see where the risks are and what needs to be prioritized.
2. Set the right security level (SL1–SL4)
IEC 62443 uses security levels that define what type of attacker the system must withstand:
SL1: Unintentional errors
SL2: Basic cyberattacks
SL3: More advanced, targeted attacks
SL4: Highly sophisticated actors (rare, used for critical infrastructure)
Most organizations start at SL2 or SL3.
The key is that not all zones require the same level.A monitoring screen does not need the same protection as a system that controls pressure, flows, or heavy machinery.
3. Define which requirements apply (policies → real-world controls)
Once zones and security levels are defined, the next step is to determine which controls are needed. IEC 62443 discusses things such as:
authentication
remote access
network segmentation
logging
change management
patching and compensating measures
secure communication
backup and recovery
You do not need to implement everything at once.The important thing is to start where the risk is highest.
4. Assess the current state – gap analysis against the requirements
When you know which requirements apply, it becomes easy to compare them with how your environment looks today.
This is where the typical “aha moment” happens:
Some areas are already well protected
Others lack basic barriers
Much can be improved without disrupting production
A good gap analysis results in a short, clear list of prioritized actions.
5. Plan improvements in reasonable, phased steps
IEC 62443 is not an “all or nothing” standard.You work iteratively and build security step by step:
address the biggest risks first
then medium risks
then refine details
The first steps often involve:
strengthening segmentation
improving remote access
enhancing logging and monitoring
reviewing supplier access
documenting responsibilities and procedures
When the foundation is in place, it becomes easier to implement more advanced parts of the standard.
6. Involve OT, IT, and the business
IEC 62443 does not work if it is treated as only an IT project or only an OT project. The standard is built on cooperation:
IT often manages networks, identities, and detection
OT manages operations and critical systems
The business manages processes and priorities
It is the collaboration that makes implementation sustainable.
7. Follow up, improve, and document
When controls are implemented, they must be tested, documented, and followed up. IEC 62443 is not static — it is a way of working.
The major benefits include:
easier environment management
increased robustness
fewer operational disruptions
more controlled handling of cyber risks
Short summary
Complying with IEC 62443 is not about extra administration or long documents. It is about:
seeing the structure
understanding the risks
and protecting production where it is most vulnerable
With the right mapping and the right priorities, the work becomes both concrete and achievable.