Systems thinking for safety and security

Abstract

The fundamental challenge facing security professionals is preventing losses, be they operational, financial or mission losses. As a result, one could argue that security professionals share this challenge with safety professionals. Despite their shared challenge, there is little evidence that recent advances that enable one community to better prevent losses have been shared with the other for possible implementation. Limitations in current safety approaches have led researchers and practitioners to develop new models and techniques. These techniques could potentially benefit the field of security. This paper describes a new systems thinking approach to safety that may be suitable for meeting the challenge of securing complex systems against cyber disruptions. Systems-Theoretic Process Analysis for Security (STPA-Sec) augments traditional security approaches by introducing a top-down analysis process designed to help a multidisciplinary team consisting of security, operations, and domain experts identify and constrain the system from entering vulnerable states that lead to losses. This new framework shifts the focus of the security analysis away from threats as the proximate cause of losses and focuses instead on the broader system structure that allowed the system to enter a vulnerable system state that the threat exploits to produce the disruption leading to the loss.