Multi-domain infrastructures are rapidly growing as "the" broad class of architecture for large-scale distributed systems that are software-defined, virtualize resources, and blend multiple clouds and networks. Acute security and dependability challenges, such as preventing insider attacks or avoiding wide-area single points of failure, require novel approaches, both to system architecture and to security and resilience mechanism implementation, to restore a high level of control over infrastructure layers and across domains, and to overcome infrastructure heterogeneity and complexity. The focus of the 1st International Workshop on Security and Dependability of Multi-Domain Infrastructures is to explore how new system architectures and mechanisms could allow the user to regain control over such infrastructures and address the previous security and resilience challenges. The XDOM0 2017 workshop aims to bring together researchers and practitioners, both from academia and industry, from Security and Dependability Communities in virtualization of systems, storage, and networking, to discuss current trends and challenges and propose novel system-level solutions for the design, implementation, and deployment of secure and resilient multi-domain infrastructures.