The workshop intends to foster an interdisciplinary discussion on how to model and analyse the socio-technical aspects of modern security systems and on how to protect such systems from socio-technical threats and attacks. It aims to stimulate an active exchange of ideas and experiences from different communities of researchers in order to identify weaknesses potentially emerging from poor usability designs and policies, from social engineering, and from deficiencies hidden in flawed interfaces and implementations. It will bring together experts in computer security and in cognitive, social, and behavioral sciences; it will collect the state of the art, identify open and emerging problems, and propose future research directions.