360° security - the holistic approach 

Comprehensive and sufficient security is not achieved by implementing only (one) technical measures in the system. An adequate security concept must include the technology used, defined processes, and the people involved, i.e., it must specify both technological and organizational measures.

Security must be understood as a mandatory system requirement. Any security-related measures must be integrated with general management structures and organizational processes. Furthermore, they must already be taken into account during the planning phase of processes, plants, and execution controls.

Many but not all threats can be defended against with appropriate technical measures, such as, for example, firewalls which filter the communication connections and only allow permitted and known connections. It is, however, important that additional measures are implemented that address personnel, procedures, policies and practices.

A basic assumption of the IEC 62443 is that security mechanisms and processes must be implemented by all three roles (as defined by the standard), rather than by a single actor.

Guiding principles

The following important guiding principles apply when developing an Information Security Management System (ISMS):

  • Security arises from the systemic interaction of the components
  • Security can only be economical if measures are taken in the right place. The principle of "equal shares for all" is just as ineffective as "a lot goes a long way".
  • To implement technical security measures, the security-related capabilities of the devices used to build automation infrastructures and systems must be utilized as far as possible. To this end, knowledge of these functionalities is necessary as well as the application-specific correct parameterization and configuration.

Further information 
For details on technical measures, please read Implementation by technical and organizational means.


Dimensions for a holistic protection

Security can only result, if all of the following three dimensions are considered in a sufficient way. Organizational and technical measures must be defined, implemented and applied/followed.

The figure below illustrates the dimensions of the holistic security measures and the following table explains details.


Dimension Offsite consideration (not ICS-specific) Onsite consideration (specific ICS in operation)
  • How were the system components (devices used to build automation infrastructures and systems) involved developed?
  • Which security-related capabilities does the system integrator have? (Policies, procedures, competence of personnel, etc., regarding design, implementation, commissioning, maintenance.)
  • Which policies and procedures does the system integrator follow during the plant design?
  • Do the plant operation processes fulfill the security requirements regarding policies, procedures etc.?
Do the policies and procedures consider and include the necessary security-related aspect regarding the
  • design
  • operation
  • maintenance
of the plant?
  • Which security-related features are provided by the components used?
  • What is implemented in the plant?
  • Which protection functions (functional security capabilities) are implemented in the plant?
    (Based on the requirements of the IEC 62443-3-3.)
  • How does the system integrator personnel follow the security-related policies and procedures?
  • How is the life cycle of each component realized by the product supplier? Consider all aspects from specification to development, test, patch management, technical support, etc.
  • How are the operating personnel instructed, trained and guided with regard to secure plant operation?
  • How strictly does the plant designers follow the security-related policies and procedures?
  • How strictly does the plant operators and maintainers follow the security-related policies and procedures?


Protection of safety-related data

The protection of safety-related data and therefore the integrity of the safety function is of particular importance.

The manipulation of the safety-related application program may result in:

  • triggering the safety function without a request having occurred in the application
  • the unavailability of the safety function so that it is no longer triggered when requested
  • the unavailability of the safety function with a simultaneous deliberate causing of the request case



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• Published/reviewed: 2023-11-02 • Revision 011 •