The current generation of Building Automation System (BAS) is designed and operated with little consideration of cyber security. Many building systems, especially the emerging Grid-interactive Efficient Buildings (GEBs), are vulnerable to cyber-attacks that may have adverse or even severe consequences, e.g., occupant discomfort, energy wastage, equipment downtime, and disruption of grid operation. Importantly, current physical behavior-based anomaly detection methods fail to differentiate cyber-attacks from equipment or operational faults. Such distinction is needed to ensure appropriate automated mitigation via control response to cyber-threats and provide actionable recommendations to the facility manager. To address these issues, the project team proposes to research, develop, and demonstrate a real-time advanced building resilient platform, called CYber Defense and REsilient System (CYDRES), deployable for existing and emerging Building Automation Systems (BAS), to empower GEB with cyber-attack-immune capabilities through multi-layer prevention, detection, and adaptation.