International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The IEC-62541 (OPC UA) standard is an important part of the Industry 4.0 reference architecture and is recommended as the only possible communication standard. A particularly important issue that is being addressed is the issue of security. Cyber security is one of the most important challenges for achieving the objectives of the Industry 4.0 initiative and of the associated cyber-physical systems (CPS). The paper analyzes the vulnerability of cyber-attacks and the main threats that threaten the security of OPC UA-based CPS and defines proven and sustainable recommendations for increasing the security of these applications.

The main objective of this study is not to identify the best machine learning model, but instead to review the main datasets, publicly available, used to train and test security solutions that employ modern classification algorithms for anomaly detection. Hence, DARPA 1998 and KDD were studied as they were the first initiatives taken in this direction, while NSL-KDD, ISCXIDS2012 and CICIDS2017 are taken in consideration for future research because of their advantages. Personalized datasets will always bring a reasonable amount of uncertainty, especially since some feature vectors used for training remain unknown. Nevertheless, training on data specific to the protected infrastructure is more efficient, from the security point of view, than training on old attack signatures.

As result of the analysis of the structure and consistency of the national security and cybersecurity in the national legislation the authors reach the conclusion that the national security in Bulgaria is government function and has system character in line with the complex system theory. The national security system together with the cybersecurity system have fully functionality of the complex system because beside structure, interaction and relations, the system feedbacks, as periodic reports and document review procedures that reshapes the links and relations. The processes of: control as a cycle, security risk management and capability planning are reflected in the national legislation and are prescriptive, as well.