  Nowadays, there are billions interconnected devices forming Cyber-Physical
Systems, Internet of Things (IoT) and Industrial Internet of Things (IIoT)
ecosystems. With an increasing number of devices and systems in use, amount and
the value of data, the risks of security breaches increase. One of these risks
is posed by open data sources, by which are meant databases, which are not
properly protected. These poorly protected databases are accessible to external
actors, which poses a serious risk to the data holder and the results of
data-related activities such as analysis, forecasting, monitoring,
decision-making, policy development, and the whole contemporary society. This
chapter aims at examining the state of the security of open data databases
representing both relational databases and NoSQL, with a particular focus on a
later category.
