The notion of Zero Trust Architecture (ZTA) has been introduced as a fine-grained defense approach. It assumes that no entities outside and inside the protected system can be trusted and therefore requires articulated and high-coverage deployment of security controls. However, ZTA is a complex notion which does not have a single design solution; rather it consists of numerous interconnected concepts and processes that need to be assessed prior to deciding on a solution. In this paper, we outline a ZTA design methodology based on cyber risks and the identification of known high security risks. We then discuss challenges related to the design and deployment of ZTA and related solutions. We also discuss the role that service technology can play in ZTA.

It is often appealing to assume that existing solutions can be directly applied to emerging engineering domains. Unfortunately, careful investigation of the unique challenges presented by new domains exposes its idiosyncrasies, thus often requiring new approaches and solutions. In this paper, we argue that the “smart” grid, replacing its incredibly successful and reliable predecessor, poses a series of new security challenges, among others, that require novel approaches to the field of cyber security. We will call this new field cyber-physical security. The tight coupling between information and communication technologies and physical systems introduces new security concerns, requiring a rethinking of the commonly used objectives and methods. Existing security approaches are either inapplicable, not viable, insufficiently scalable, incompatible, or simply inadequate to address the challenges posed by highly complex environments such as the smart grid. A concerted effort by the entire industry, the research community, and the policy makers is required to achieve the vision of a secure smart grid infrastructure.

In recent years, organizations ranging from defense and other government institutions to commercial enterprises, research labs, etc., have witnessed an increasing amount of sophisticated insider attacks that manage to bypass existing security controls. Insider threats are staged by either disgruntled employees, or employees engaged in malicious activities such as industrial espionage. The objectives of such threats range from sabotage, e.g., in order to disrupt the completion of a project, to exfiltration of sensitive data such as trade secrets, patents, etc. Insiders are often skilled and motivated individuals with good knowledge of internal security measures in the organization. They devise effective and carefully planned attacks, prepared over long periods of time and customized to inflict maximum damage. Such attacks are difficult to detect and protect against, because insiders have the proper credentials to access services and systems within the organization, and possess knowledge that may allow them to deceive network defense controls. As a result, a large number of hosts may be taken over, allowing malicious insiders to maintain control over the network even after leaving the organization.