CLOUD-BASED INTERNET-OF-THINGS (IoT) is one of the emerging topics in IoT and Cloud Computing (CC). In addition to those found in CC and IoT, a Cloud-based IoT infrastructure inherits pros and cons of several other technologies and computing approaches. The distributed nature of a Cloud-based IoT infrastructure is prone to different threats and vulnerabilities related to technological and human-centric factors as well as strategic decisions in design and implementation of a Cloud-based IoT. This chapter explores Cloud-based IoT from security perspective. The technologies and design issues for Cloud-based IoT are explored in initial discussion. The security threats for a Cloud-based IoT infrastructure is addressed afterwards. Since CC plays a major role in Cloud-based IoT scenario; threats, security concerns, and vulnerabilities of CC are considered, which are then mapped into security threats and vulnerabilities for Cloud-based IoT. The security issues and threats are considered through three key factors, namely, technological, human, and governance. This chapter concludes by summarising �findings and reflecting on key insights from the fi�ndings.