Cyber security support to Network Rail

Helios carried out an independent assessment of signalling infrastructure using the Cyber Assessment Framework from NCSC, providing insights into ways to increase the effectiveness of Network Rail’s defences against cyber-attack and ransomware.


Aecom Limited have a managed services framework agreement with Network Rail. Helios were subcontracted via Egis Rail to provide cyber security capability. Helios were asked to provide a maturity assessment on security approaches across Network Rail's signalling infrastructure.

This case study is an example of Helios working within complex business partnerships and supporting critical transport infrastructure in the UK.


Helios, under contract to Network Rail (NR) via Aecom and Egis Rail, was asked to review and update a set of CAF (Cyber Assessment Framework) assessments and recommend practical remediations where necessary to the Signalling and E&P (Electrification and Plant) Systems.

Role of Helios

Each of the identified critcal systems within the Signalling and E&P (Electrification and Plant) groups was assessed for CAF (Cyber Assessment Framework) objectives, using the following sources of information:

  • Published documentation provided by Network Rail and suppliers
  • Interviews with internal Network Rail System owners and experts
  • Interviews/questionnaires with system suppliers

The approach to the CAF assessments was to provide a technical document-based review of each system, based on available documentation, policies and procedures, which was then suplemented by input from operational staff who have working knowledge of the system 'as operated'. This provides valuable insight into the system and a more realistic view of the system's vulnerability to cyber threats. It also provides valuable insight into organisational and cultural factors that can be critical factors in the effectiveness of human defences againist cyber threats.

Helios produced a detailed report covering our assessment of critical E&P (Electrification and Plant) and Signalling systems against the Department for Transport CAF (Cyber Assessment framework). The report also included remediation recommendations resulting from the assessment.


Alongside detailed system-specific remediation recommendations, the final report identified a number of general themes which provided insights into suitable approaches and activities which could further increase the effectiveness of Network Rail's defences against cyber-attack and ransomware. These common themes provided an opportunity to implement a more central solution to provide compliance benefits across multiple systems. Helios provided both general remediations and system-specific remediations in the final report. The remediation plans focus on the following aspects:

  • Opportunities to further enhance physical & access security arrangements to defend against unauthorised and inadvertant changes to systems
  • Identification of system segmentation opportunities to limit the spread of viruses or ransomware
  • Development of metrics to effectively evaulate and monitor identified cyber-risks
  • Steps to control portable & removable devices in the context of operational systems
  • Establishing frameworks and processes which collect evidence needed for future assessments and to demonstrate continued compliance to regulation
  • To make future CAF assessments more straightforward, Helios also offered additional recommendations to improve the security management processes, based on the lessons learned in this work.

For further information on this project please contact Andy Boff.

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