Specification of Countermeasures for CYRAIL What countermeasures to mitigate the risks from the risk analysis?

Objective of countermeasures specification Identify threats and vulnerabilities 76 threats identified (ISO 27005 standard & threat analysis) Determine impact Safety, Finance, Operational Determine likelihood Time, Expertise, Knowledge, Opportunity, Equipment Calculate unmitigated risk Risk = Impact x Likelihood Determine Security Level Target To identify the most critical security zones Identify countermeasures To mitigate the risks Analysis of the residual risk Below tolerable risk?

Widely-distributed software - Software Methodology Countermeasures are specified by zone and by threat. Each countermeasure is defined according the security level target of the zone. Example of the Command-onboard zone: Threat Vulnerability Risk Asset Countermeasures Corruption of data Widely-distributed software - Software Corrupting the data an attacked can change the software to create fake information in the asset BTS Logging and monitor device. Define a management policy for patches (systematic, periodic or ad hoc) that is suited to the functional constraints. For example, define priorities for deployment of patches, verify ascending compatibility, and interoperability. Use Reliable NTP (internal real time reference) RBC Logging and monitor device. Local ERTMS Control CF BTS REQ Use an electronic certificate to timestamp data Applying application programs to the wrong data in terms of time - Software These countermeasures may restrict the functionality of the system and therefore, they must not impact the safety of the system. => Focus on the assessment of the fail-safe concept to fall back to a safe operational mode. In some cases, no countermeasure is available to a threat. It is usually due to the fact that the affected asset cannot embed cyber security related countermeasure.

Synthesis of Countermeasures Cyber countermeasures Other countermeasures

Countermeasure examples (conduits) Type Countermeasure Assets Risk Threat Threat class Process & Human actions Set some Key Performance Indicator (KPI) in order to evaluate the level of Quality of Service served by the system and logging. Monitor and alert the gap between normal activities and abnormal activities. Define Thresholds and send an alert. ERTMSBalise The track-to-train communication is jammed Electromagnetic radiation T.RA Occupancy The interlocking-to-track communication is jammed Signalling The communication between zones connected to the Signalling network is jammed Data Protection Control integrity of message with a robust security algorithm (). Use double authentication. Make sure that integrity is controlled by the server and not by the End user.