A Model Based System Security Goal Elicitation Method Applied to a Space Traffic Management System

A Model Based Systems Engineering (MBSE) approach to eliciting functional security goals for a notional spaced-based traffic management system highlights the utility of Eliciting Goals for Requirement Engineering of Secure Systems (EGRESS), a new methodology. EGRESS leverages a recently released MBSE standard, the Object Modeling Group (OMG) Risk Analysis and Assessment Modeling Language (RAAML), to conduct security analysis on a system of interest. The demonstration of the EGRESS method includes the use of the Systems Theoretic Process Analysis (STPA), an industry best practice approach to hazard identification and analysis. The artifacts from the EGRESS approach will be captured using RAMML in an MBSE tool as applied to a notional space-based traffic management system (STMS). Modeling a system in a digital environment provides traceability between the potential points of failure and risk assessments. Linking safety and security impacts to system assets and stakeholder needs enables design decisions and risk treatment at the appropriate level of abstraction. Early identification of security goals accommodates implementation as a ‘Design For Consideration’ and is treated on the same level as functional and safety requirements during the system design process. EGRESS uniquely provides direct traceability for security and digital representation that facilitates the identification of failure modes along with the required remediation. This work demonstrates the utility of EGRESS, MBSE, and RAAML to secure system design for a representative space-based cyber-physical system (CPS).