1. What are the Resilience Mechanisms? Hugo Pereira Evoleo Technologies
CYRAIL Final Conference
Paris,
What are the Resilience Mechanisms?
Hugo Pereira
Evoleo Technologies

2. Cyber Resilience
Cyber Resilience as the ability to anticipate, withstand, recover from and adapt to adverse conditions, stresses, attacks, or compromises on cyber resources.
Cyber resilience has mission assurance as main goal, that is, it aims to resist sophisticated and evolving adversities while continuing to provide a given functionality or service at all times.
-> Definition (goals): anticipate, withstand, recover and adapt
-> Main objective: continue to provide or recover quickly a functionality or system during/after a successful attack
-> Understand the adversary, Prepare, Prevent / Avoid, Continue, Constrain, Reconstruct, Transform, Re-architect
Main references:
Cyber Resiliency Design Principles - Selective Use Throughout the Lifecycle and in Conjunction with Related Disciplines
Cyber Resiliency Engineering Framework

3. Cyber Resilience Design Principles
Cyber resilience design principles should be applied during in the planning or development phases of systems, architectures and organization’s risk management strategies.
Focus on common critical assets
Maintain redundancy
Support agility and architect for adaptability
Make resources location-versatile
Reduce attack surfaces
Leverage health and status data
Assume compromised resources
Maintain situational awareness
Expect adversaries to evolve
Manage resources (risk-) adaptively
Limit the need for trust
Maximize transience; minimize persistence
Control visibility and use
Determine ongoing trustworthiness
Contain and exclude behaviors
Change or disrupt the attack surface
Layer and partition defences
Make unpredictability and deception user- transparent
Plan and manage diversity
Cyber resilience design principles should be applied during in the planning or development phases of systems, architectures and organization’s risk management strategies.
Their application should be tailored according to the system characteristics, enterprise business decisions, preferences, financial resources, legal and contractual requirements, previous investments, culture, known attacker strategies.
Strategic design principles are applied throughout the systems engineering process and can be used guide the selection and application of structural design principles in different parts of the architecture.
Structural design principles refer to those that directly affect system architecture and design. They can be applied in more specific areas of the architecture and be tailored according to system necessities

4. Cyber Resilience Techniques
Cyber resilience techniques are used to support the application of the design principles.
Adaptive Response
Non-Persistence
Analytic Monitoring
Privilege Restriction
Coordinated Defence
Realignment
Deception
Redundancy
Diversity
Segmentation / Isolation
Dynamic Positioning
Substantiated Integrity
Dynamic Representation
Unpredictability
Cyber resilience techniques are used to support the application of the design principles.
Consequently, they can also be tailored according to the system and environment. Different resilience techniques can achieve the same goal in different systems.
Despite some being well known cyber security mechanisms, motivation for using these techniques comes from how to best mitigate or eliminate effects of successful attacks, instead of how to prevent attacks from being successful.

5. Relation between cyber resilience principles, objectives and techniques
Based on MITRE’s reference.
S – Supports achieving the objective
R – Requires use of cyber resiliency technique (or one or more approaches) to achieve specific effects on adversary
U – Can use cyber resiliency technique (or one or more approaches)
X – Can be combined with use of cyber resiliency technique (or one or more)

6. CYRAIL Zones and Conduits
Wayside_1
KMC
Wayside_2
Control Center Data
Signal
OnBoard
Command-onboard
ERTMSBalise
Maintain
Occupancy
JRU
Signalling
Movement
From D3.2 – Security Analysis and Vulnerability List of the Use Cases

7. CYRAIL Zones and Conduits

8. Applying cyber resilience to CYRAIL's zones and conduits
Zones / Conduits
Threat Class
Cyber Resilience Techniques
Adaptive Response
Analytic Monitoring
Coordinated Defence
Deception
Diversity
Dynamic Positioning
Dynamic Representation
Non-Persistence
Privilege Restriction
Realignment
Redundancy
Segmentation / Isolation
Substantiated Integrity
Unpredictability
Wayside_1
T.IAC + T.UC X
T.IAC + T.SI
T.IAC + T.RA
Wayside_2
Signal
Command-onboard
T.IAC
Maintain
JRU
Movement
KMC
T.IAC + T.DC
T.DC
T.UC
Control Center_ Data
Onboard
ERTMSBalise
T.RA
Occupancy
Signalling
An exercise was made to relate a relation between the Cyber Resilience concepts and the Project use case.
Thus, a mapping of the cyber resilience techniques to the threats of the zones and conduits has been done. Taking into account which cyber resilience objective is expected to be achieved in each case (zone)

9. Final Thoughts
During the state of the art research, limited or non-existing references were found specifically describing how cyber resilience can be integrated into railway cyber systems.
Cyber resilience is necessary to effectively protect against sophisticated and evolving adversaries.
Cyber resilience design principles should be applied during in the planning or development phases of systems, architectures and organization’s risk management strategies.
Cyber resilience techniques are used to support the application of the design principles. Despite some being well known cyber security mechanisms, motivation for using these techniques comes from how to best mitigate or eliminate effects of successful attacks, instead of how to prevent attacks from being successful.
The application of both cyber resilience design principles and techniques should be tailored according to the system and its environment (e.g. enterprise business decisions and preferences, known attacker strategies).
A guideline for the application of cyber resilience concepts in railway related cyber systems was presented, by associating cyber resilience techniques with the railway zones.