As one of the Internet of Things (IoT) technology, the Sigfox network has brought digitization to smart spaces in terms of automation and operational management, for example, smart building and cities. However, the large-scale installed sensors and devices expand the attack surfaces, as a vulnerable device exposed to cyber threats may also cause physical harm. Thus, monitoring and understanding cybersecurity status in a smart environment is critical. In this paper, we present the cyber-threats analysis of the layered Sigfox IoT system. To increase cybersecurity awareness in smart residential buildings, we propose visual analytic dashboards for monitoring both cybersecurity and safety status. The developed dashboards are tailored to three user groups - Admin users, House managers and Residents. Such security dashboards are applicable to other IoT use cases such as smart cities and smart logistics.