Modelling and Analysing Socio-Technical Systems

Modern organisations are complex, socio-technical systems consisting of a mixture of physical infrastructure, human actors, policies and processes. An increasing number of attacks on these organisations exploits vulnerabilities on all different levels, for example combining a malware attack with social engineering. Due to this combination of attack steps on technical and social levels, risk assessment in socio-technical systems is complex. Therefore, established risk assessment methods often abstract away the internal structure of an organisation and ignore human factors when modelling and assessing attacks. In our work we model all relevant levels of socio-technical systems, and propose evaluation techniques for analysing the security properties of the model. Our approach simplifies the identification of possible attacks and provides qualified assessment and ranking of attacks based on the expected impact. We demonstrate our approach on a home-payment system. The system is specifically designed to help elderly or disabled people, who may have difficulties leaving their home, to pay for some services, e.g., care-taking or rent. The payment is performed using the remote control of a television box with a contactless payment card (see Figure 1). When a transfer is initiated, a password is needed in order to authenticate the owner of the card.