Biblio

The mass integration and deployment of intelligent technologies within critical commercial, industrial and public environments have a significant impact on business operations and society as a whole. Though integration of these critical intelligent technologies pose serious embedded security challenges for technology manufacturers which are required to be systematically approached, in-line with international security regulations.This paper establish security foundation for such intelligent technologies by deriving embedded security requirements to realise the core security functions laid out by international security authorities, and proposing microarchitectural characteristics to establish cyber resilience in embedded systems. To bridge the research gap between embedded and operational security domains, a detailed review of existing embedded security methods, microarchitectures and design practises is presented. The existing embedded security methods have been found ad-hoc, passive and strongly rely on building and maintaining trust. To the best of our knowledge to date, no existing embedded security microarchitecture or defence mechanism provides continuity of data stream or security once trust has broken. This functionality is critical for embedded technologies deployed in critical infrastructure to enhance and maintain security, and to gain evidence of the security breach to effectively evaluate, improve and deploy active response and mitigation strategies. To this end, the paper proposes three microarchitectural characteristics that shall be designed and integrated into embedded architectures to establish, maintain and improve cyber resilience in embedded systems for next-generation critical infrastructure.

Traditional firewalls, Intrusion Detection Systems(IDS) and network analytics tools extensively use the `flow' connection concept, consisting of five `tuples' of source and destination IP, ports and protocol type, for classification and management of network activities. By analysing flows, information can be obtained from TCP/IP fields and packet content to give an understanding of what is being transferred within a single connection. As networks have evolved to incorporate more connections and greater bandwidth, particularly from ``always on'' IoT devices and video and data streaming, so too have malicious network threats, whose communication methods have increased in sophistication. As a result, the concept of the 5 tuple flow in isolation is unable to detect such threats and malicious behaviours. This is due to factors such as the length of time and data required to understand the network traffic behaviour, which cannot be accomplished by observing a single connection. To alleviate this issue, this paper proposes the use of additional, two tuple and single tuple flow types to associate multiple 5 tuple communications, with generated metadata used to profile individual connnection behaviour. This proposed approach enables advanced linking of different connections and behaviours, developing a clearer picture as to what network activities have been taking place over a prolonged period of time. To demonstrate the capability of this approach, an expert system rule set has been developed to detect the presence of a multi-peered ZeuS botnet, which communicates by making multiple connections with multiple hosts, thus undetectable to standard IDS systems observing 5 tuple flow types in isolation. Finally, as the solution is rule based, this implementation operates in realtime and does not require post-processing and analytics of other research solutions. This paper aims to demonstrate possible applications for next generation firewalls and methods to acquire additional information from network traffic.

Complex embedded systems often contain hard to find vulnerabilities which, when exploited, have potential to cause severe damage to the operating environment and the user. Given that threats and vulnerabilities can exist within any layer of the complex eco-system, OEMs face a major challenge to ensure security throughout the device life-cycle To lower the potential risk and damage that vulnerabilities may cause, OEMs typically perform application threat analysis and security modelling. This process typically provides a high level guideline to solving security problems which can then be implemented during design and development. However, this concept presents issues where new threats or unknown vulnerability has been discovered. To address this issue, we propose a policy-based security modelling approach, which utilises a configurable policy engine to apply new policies that counter serious threats. By utilising this approach, the traditional security modelling approaches can be enhanced and the consequences of a new threat greatly reduced. We present a realistic use case of connected car, applying several attack scenarios. By utilising STRIDE threat modelling and DREAD risk assessment model, adequate policies are derived to protect the car assets. This approach poses advantages over the standard approach, allowing a policy update to counter a new threat, which may have otherwise required a product redesign to alleviate the issue under the traditional approach.