National foreword

This Published Document is the UK implementation of CLC/TS 50701:2021.

The UK participation in its preparation was entrusted to Technical Committee GEL/9, Railway Electrotechnical Applications.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

This publication is not to be regarded as a British Standard.

Compliance with a Published Document cannot confer immunity from legal obligations.

This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 July 2021.

This Technical Specification was approved by CENELEC on 2021-05-11.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

European foreword

This document (CLC/TS 50701:2021) has been prepared by CLC/TC 9X “Electrical and electronic applications for railways”.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national committee. A complete listing of these bodies can be found on the CENELEC website.

Introduction

The aim of this document is to introduce the requirements as well as recommendations to address cybersecurity within the railway sector.

Due to digitization and the need for more performance and better maintainability, previously isolated industrial systems are now connected to large networks and increasingly use standard protocols and commercial components. Because of this evolution, cybersecurity becomes a key topic for these industrial systems, including critical systems such as railway systems.

The purpose of this document is that, when a railway system is compliant to this document, it can be demonstrated that this system is at the state of the art in terms of cybersecurity, that it fulfils its targeted Security Level and that its security is maintained during its operation and maintenance.

This document intends to:

provide requirements and guidance on cybersecurity activities and deliverables
be adaptable and applicable to various system lifecycles
be applicable for both safety and non-safety related systems
identify interfaces between cybersecurity and other disciplines contributing to railway system lifecycles
be compatible and consistent with EN 50126‑1 when it is applied to the system under consideration
due to lifecycle differences between safety and cybersecurity, separate safety approval and cybersecurity acceptance as much as possible
identify the key synchronization points related to cybersecurity between system integrator and asset owner
provide harmonized and standardized way to express technical cybersecurity requirements
provide cybersecurity design principles promoting simple and modular systems
allow the usage of market products such as industrial COTS compliant with the 62443 series.

1 Scope

This document provides the railway operators, system integrators and product suppliers, with guidance and specifications on how cybersecurity will be managed in the context of EN 50126‑1 RAMS lifecycle process. This document aims at the implementation of a consistent approach to the management of the security of the railway systems. This document can also be applied to the security assurance of systems and components/equipment developed independently of EN 50126‑1:2017.

This document applies to Communications, Signalling and Processing domain, to Rolling Stock and to Fixed Installations domains. It provides references to models and concepts from which requirements and recommendations can be derived and that are suitable to ensure that the residual risk from security threats is identified, supervised and managed to an acceptable level by the railway system duty holder. It presents the underlying security assumptions in a structured manner.

This document does not address functional safety requirements for railway systems but rather additional requirements arising from threats and related security vulnerabilities and for which specific measures and activities need to be taken and managed throughout the lifecycle. The aim of this document is to ensure that the RAMS characteristics of railway systems / subsystems / equipment cannot be reduced, lost or compromised in the case of intentional attacks.

The security models, the concepts and the risk assessment process described in this document are based on or derived from IEC/EN IEC 62443 series standards. This document is consistent with the application of security management requirements contained within IEC 62443‑2‑1 which in turn are based on EN ISO/IEC 27001 and EN ISO 27002.

2 Normative references

3 Terms, definitions and abbreviations

3.1 Terms and definitions

3.2 Abbreviations

4 Railway system overview

4.1 Introduction

4.2 Railway asset model

4.3 Railway physical architecture model

4.4 High-level railway zone model

5 Cybersecurity within a railway application lifecycle

5.1 Introduction

5.2 Railway application and product lifecycles

5.3 Activities, synchronization and deliverables

5.4 Cybersecurity context and cybersecurity management plan

5.5 Relationship between cybersecurity and essential functions

5.6 Cybersecurity assurance process

6 System definition and initial risk assessment

6.1 Introduction

6.2 Identification of the system under consideration

6.3 Initial risk assessment

6.4 Partitioning of the SuC

6.5 Output and documentation

7 Detailed risk assessment

7.1 General aspects

7.2 Establishment of cybersecurity requirements

8 Cybersecurity requirements

8.1 Objectives

8.2 System security requirements

8.3 Apportionment of cybersecurity requirements

9 Cybersecurity assurance and system acceptance for operation

9.1 Overview

9.2 Cybersecurity case

9.3 Cybersecurity verification

9.4 Cybersecurity validation

9.5 Cybersecurity system acceptance

10 Operational, maintenance and disposal requirements

10.1 Introduction

10.2 Vulnerability management

10.3 Security patch management

Bibliography

PD CLC/TS 50701:2021

Railway applications. Cybersecurity

Published:

31 Jul 2021

Withdrawn:

21 Aug 2023