  The Internet of Things (IoT) is rapidly changing our society to a world where
every "thing" is connected to the Internet, making computing pervasive like
never before. This tsunami of connectivity and data collection relies more and
more on the Cloud, where data analytics and intelligence actually reside. Cloud
computing has indeed revolutionized the way computational resources and
services can be used and accessed, implementing the concept of utility
computing whose advantages are undeniable for every business. However, despite
the benefits in terms of flexibility, economic savings, and support of new
services, its widespread adoption is hindered by the security issues arising
with its usage. From a security perspective, the technological revolution
introduced by IoT and Cloud computing can represent a disaster, as each object
might become inherently remotely hackable and, as a consequence, controllable
by malicious actors. While the literature mostly focuses on security of IoT and
Cloud computing as separate entities, in this article we provide an up-to-date
and well-structured survey of the security issues of Cloud computing in the IoT
era. We give a clear picture of where security issues occur and what their
potential impact is. As a result, we claim that it is not enough to secure IoT
devices, as cyber-storms come from Clouds.
