Biblio

Cyber-Physical Systems (CPS) attract growing interest from architects and attackers, given their potential effect on privacy and safety of ecosystems and users. Architectural tactics have been proposed as a design-time abstraction useful to guide and evaluate systems design decisions that address specific system qualities, but there is little published evidence of how Security Tactics help to mitigate security threats in the context of Cyber-Physical Systems. This article reports the principled derivation of architectural tactics for an actual SCADA-SAP bridge, where security was the key concern; the key inputs were (1) a well-known taxonomies of architectural tactics, and (2) a detailed record of trade-offs among these tactics. The project architects used client-specified quality attributes to identify relevant tactics in the taxonomy, and information on their trade-offs to guide top-level decisions on system global shape. We venture that all architectural tactics taxonomies should be enriched with explicit trade-offs, allowing architects to compare alternative solutions that seem equally good on principle but are not so in practice.

Data fusion, as a means to improve aircraft and air traffic safety, is a recent focus of some researchers and system developers. Increases in data volume and processing needs necessitate more powerful hardware and more flexible software architectures to satisfy these needs. Such improvements in processed data also mean the overall system becomes more complex and correspondingly, resulting in a potentially significantly larger cyber-attack space. Today's multicore processors are one means of satisfying the increased computational needs of data fusion-based systems. When coupled with a real-time operating system (RTOS) capable of flexible core and application scheduling, large cabinets of (power hungry) single-core processors may be avoided. The functional and assurance capabilities of such an RTOS can be critical elements in providing application isolation, constrained data flows, and restricted hardware access (including covert channel prevention) necessary to reduce the overall cyber-attack space. This paper examines fundamental considerations of a multiple independent levels of security (MILS) architecture when supported by a multicore-based real-time operating system. The paper draws upon assurance activities and functional properties associated with a previous Common Criteria evaluation assurance level (EAL) 6+ / High-Robustness Separation Kernel certification effort and contrast those with activities performed as part of a MILS multicore related project. The paper discusses key characteristics and functional capabilities necessary to achieve overall system security and safety. The paper defines architectural considerations essential for scheduling applications on a multicore processor to reduce security risks. For civil aircraft systems, the paper discusses the applicability of the security assurance and architecture configurations to system providers looking to increase their resilience to cyber threats.

The Department of Defense (DoD) manages capabilities through the Joint Interoperability and Capability Development System (JCIDS) process. As part of this process, sponsors develop a series of DoD Architecture Framework (DoDAF) products to assist analysts understand the proposed capability and how it fits into the broader network of DoD legacy systems and systems under development. However, the Joint Staff, responsible for executing the JCIDS process, often analyzes these architectures in isolation without considering the broader network of systems. DoD leadership, the Government Accountability Organization, and others have noted the lack of the DoD's ability to manage the broader portfolio of capabilities in various reports and papers. Several efforts have proposed merging DoDAF architecture into a larger meta-architecture based on individual system architectures. This paper specifically targets the Systems View 3 (SV-3), System-to-system matrix, as an opportunity to merge multiple DoDAF architecture views into a network of system and understand the potential benefits associated with analyzing a broader perspective. The goal of merging multiple SV-3s is to better understand the interoperability of a system within the network of DoD systems as network metrics may provide insights into the relative interoperability of a DoD system. Currently, the DoD's definition of interoperability focuses on the system or capability's ability to enter and operate within the DoD Information Network (DoDIN); however, this view limits the definition of interoperability as it focuses solely on information flows and not resource flows or physical connections that should be present in a SV-3. The paper demonstrates the importance of including all forms of connections between systems in a network by comparing network metrics associated with the different types of connections. Without a complete set of DoDAF architectures for each system within the DoD and based on the potential classification of these products, the paper collates data that should be included in an SV-3 from open source, unclassified references to build the overall network of DoD systems. From these sources, a network of over 300 systems with almost 1000 connections emerges based on the documented information, resource, and physical connections between these legacy and planned DoD systems. With this network, the paper explores the quantification of individual system's interoperability through the application of nodal and network metrics from social network analysis (SNA). A SNA perspective on a network of systems provides additional insights beyond traditional network analysis because of the emphasis on the importance of nodes, systems, in the network as well as the relationship, connections, between the nodes. Finally, the paper proposes future work to explore the quantification of additional attributes of systems as well as a method for further validating the findings.

Security issues emerging out of the constantly evolving software applications became a huge challenge to software security experts. In this paper, we propose a prototype to detect vulnerabilities by identifying their architectural sources and also use security patterns to mitigate the identified vulnerabilities. We emphasize the need to consider architectural relations to introduce an effective security solution. In this research, we focused on the taint-style vulnerabilities that can induce injection-based attacks like XSS, SQLI in web applications. With numerous tools available to detect the taint-style vulnerabilities in the web applications, we scanned for the presence of repetition of a vulnerable code pattern in the software. Very importantly, we attempted to identify the architectural source files or modules by developing a tool named ArT Analyzer. We conducted a case study on a leading health-care software by applying the proposed architectural taint analysis and identified the vulnerable spots. We could identify the architectural roots for those vulnerable spots with the use of our tool ArT Analyzer. We verified the results by sharing it with the lead software architect of the project. By adopting an architectural solution, we avoided changes to be done on 252 different lines of code by merely introducing 2 lines of code changes at the architectural roots. Eventually, this solution was integrated into the latest updated release of the health-care software.

In the development process of critical systems, one of the main challenges is to provide early system validation and verification against vulnerabilities in order to reduce cost caused by late error detection. We propose in this paper an approach that, firstly allows formally describe system security specifications, thanks to our suggested extended attack tree. Secondly, static and dynamic system modeling by using a SysML connectivity profile to model error propagation is introduced. Finally, a model checker has been used in order to validate system specifications.

Engineering complex distributed systems is challenging. Recent solutions for the development of cyber-physical systems (CPS) in industry tend to rely on architectural designs based on service orientation, where the constituent components are deployed according to their service behavior and are to be understood as loosely coupled and mostly independent. In this paper, we develop a workflow that combines contract-based and CPS model-based specifications with service orientation, and analyze the resulting model using fault injection to assess the dependability of the systems. Compositionality principles based on the contract specification help us to make the analysis practical. The presented techniques are evaluated on two case studies.

Cloud-based cyber-physical systems, like vehicle and intelligent transportation systems, are now attracting much more attentions. These systems usually include large-scale distributed sensor networks covering various components and producing enormous measurement data. Lots of modeling languages are put to use for describing cyber-physical systems or its aspects, bringing contribution to the development of cyber-physical systems. But most of the modeling techniques only focuse on software aspect so that they could not exactly express the whole cloud-based cyber-physical systems, which require appropriate views and tools in its design; but those tools are hard to be used under systemic or object-oriented methods. For example, the widest used modeling language, UML, could not fulfil the above design's requirements by using the foremer's standard form. This paper presents a method designing the cloud-based cyber-physical systems with AADL, by which we can analyse, model and apply those requirements on cloud platforms ensuring QoS in a relatively highly extensible way at the mean time.

The recently applied General Data Protection Regulation (GDPR) aims to protect all EU citizens from privacy and data breaches in an increasingly data-driven world. Consequently, this deeply affects the factory domain and its human-centric automation paradigm. Especially collaboration of human and machines as well as individual support are enabled and enhanced by processing audio and video data, e.g. by using algorithms which re-identify humans or analyse human behaviour. We introduce most significant impacts of the recent legal regulation change towards the automations domain at a glance. Furthermore, we introduce a representative scenario from production, deduce its legal affections from GDPR resulting in a privacy-aware software architecture. This architecture covers modern virtualization techniques along with authorization and end-to-end encryption to ensure a secure communication between distributes services and databases for distinct purposes.

Cyber-physical systems (CPS) research leverages the expertise of researchers from multiple domains to engineer complex systems of interacting physical and computational components. An approach called co-simulation is often used in CPS conceptual design to integrate the specialized tools and simulators from each of these domains into a joint simulation for the evaluation of design decisions. Many co-simulation platforms are being developed to expedite CPS conceptualization and realization, but most use intrusive modeling and communication libraries that require researchers to either abandon their existing models or spend considerable effort to integrate them into the platform. A significant number of these co-simulation platforms use the High Level Architecture (HLA) standard that provides a rich set of services to facilitate distributed simulation. This paper introduces a simple gateway that can be readily implemented without co-simulation expertise to adapt existing models and research infrastructure for use in HLA. An open-source implementation of the gateway has been developed for the National Institute of Standards and Technology (NIST) co-simulation platform called the Universal CPS Environment for Federation (UCEF).

Cyber-physical systems contribute to building new infrastructure in the modern world. These systems help realize missions reducing costs and risks. The seas being a harsh and dangerous environment are a perfect application of them. Unmanned Surface vehicles (USV) allow realizing normal and new tasks reducing risk and cost i.e. surveillance, water cleaning, environmental monitoring or search and rescue operations. Also, as they are unmanned vehicles they can extend missions to unpleasing and risky weather conditions. The novelty of these systems makes that new command and control platforms need to be developed. In this paper, we describe an implemented architecture with 5 separated levels. This structure increases security by defining roles and by limiting information exchanges.

Microservice Architectures (MSA) structure applications as a collection of loosely coupled services that implement business capabilities. The key advantages of MSA include inherent support for continuous deployment of large complex applications, agility and enhanced productivity. However, studies indicate that most MSA are homogeneous, and introduce shared vulnerabilites, thus vulnerable to multi-step attacks, which are economics-of-scale incentives to attackers. In this paper, we address the issue of shared vulnerabilities in microservices with a novel solution based on the concept of Moving Target Defenses (MTD). Our mechanism works by performing risk analysis against microservices to detect and prioritize vulnerabilities. Thereafter, security risk-oriented software diversification is employed, guided by a defined diversification index. The diversification is performed at runtime, leveraging both model and template based automatic code generation techniques to automatically transform programming languages and container images of the microservices. Consequently, the microservices attack surfaces are altered thereby introducing uncertainty for attackers while reducing the attackability of the microservices. Our experiments demonstrate the efficiency of our solution, with an average success rate of over 70% attack surface randomization.

The defense-in-depth approach has been widely recommended for designing critical information infrastructure, however, the lack of holistic design guidelines makes it difficult for many organizations to adopt the concept. Therefore, this paper proposes a holistic architectural framework and guidelines based on ring-based nested network zones for designing such highly secured information systems. This novel security architectural framework and guidelines offer the overall structural design and implementation options for holistically designing the N-tier/shared nothing system architectures. The implementation options, e.g. for the zone's perimeters, are recommended to achieve different capability levels of security or to trade off among different required security attributes. This framework enables the adaptive capability suitable for different real-world contexts. This paper also proposes an attack-hops verification approach as a tool to evaluate the architectural design.

An important principle in computational security is to reduce the attack surface, by maintaining the Trusted Computing Base (TCB) small. Even so, no security technique ensures full protection against any adversary. Thus, sensitive applications should be designed with several layers of protection so that, even if a layer might be violated, sensitive content will not be compromised. In 2015, Intel released the Software Guard Extensions (SGX) technology in its processors. This mechanism allows applications to allocate enclaves, which are private memory regions that can hold code and data. Other applications and even privileged code, like the OS kernel and the BIOS, are not able to access enclaves' contents. This paper presents a novel password file protection scheme, which uses Intel SGX to protect authentication credentials in the PAM authentication framework, commonly used in UNIX systems. We defined and implemented an SGX-enabled version of the pam\_unix.so authentication module, called UniSGX. This module uses an SGX enclave to handle the credentials informed by the user and to check them against the password file. To add an extra security layer, the password file is stored using SGX sealing. A threat model was proposed to assess the security of the proposed solution. The obtained results show that the proposed solution is secure against the threat model considered, and that its performance overhead is acceptable from the user point of view. The scheme presented here is also suitable to other authentication frameworks.

This paper proposes an architecture of Secure Shell (SSH) honeypot using port knocking and Intrusion Detection System (IDS) to learn the information about attacks on SSH service and determine proper security mechanisms to deal with the attacks. Rapid development of information technology is directly proportional to the number of attacks, destruction, and data theft of a system. SSH service has become one of the popular targets from the whole vulnerabilities which is existed. Attacks on SSH service have various characteristics. Therefore, it is required to learn these characteristics by typically utilizing honeypots so that proper mechanisms can be applied in the real servers. Various attempts to learn the attacks and mitigate them have been proposed, however, attacks on SSH service are kept occurring. This research proposes a different and effective strategy to deal with the SSH service attack. This is done by combining port knocking and IDS to make the server keeps the service on a closed port and open it under user demand by sending predefined port sequence as an authentication process to control the access to the server. In doing so, it is evident that port knocking is effective in protecting SSH service. The number of login attempts obtained by using our proposed method is zero.

Active authentication is the problem of continuously verifying the identity of a person based on behavioral aspects of their interaction with a computing device. In this paper, we collect and analyze behavioral biometrics data from 200 subjects, each using their personal Android mobile device for a period of at least 30 days. This data set is novel in the context of active authentication due to its size, duration, number of modalities, and absence of restrictions on tracked activity. The geographical colocation of the subjects in the study is representative of a large closed-world environment such as an organization where the unauthorized user of a device is likely to be an insider threat: coming from within the organization. We consider four biometric modalities: 1) text entered via soft keyboard, 2) applications used, 3) websites visited, and 4) physical location of the device as determined from GPS (when outdoors) or WiFi (when indoors). We implement and test a classifier for each modality and organize the classifiers as a parallel binary decision fusion architecture. We are able to characterize the performance of the system with respect to intruder detection time and to quantify the contribution of each modality to the overall performance.

Secure by design is an approach to developing secure software systems from the ground up. In such approach, the alternate security tactics are first thought, among them, the best are selected and enforced by the architecture design, and then used as guiding principles for developers. Thus, design flaws in the architecture of a software system mean that successful attacks could result in enormous consequences. Therefore, secure by design shifts the main focus of software assurance from finding security bugs to identifying architectural flaws in the design. Current research in software security has been neglecting vulnerabilities which are caused by flaws in a software architecture design and/or deteriorations of the implementation of the architectural decisions. In this paper, we present the concept of Common Architectural Weakness Enumeration (CAWE), a catalog which enumerates common types of vulnerabilities rooted in the architecture of a software and provides mitigation techniques to address them. The CAWE catalog organizes the architectural flaws according to known security tactics. We developed an interactive web-based solution which helps designers and developers explore this catalog based on architectural choices made in their project. CAWE catalog contains 224 weaknesses related to security architecture. Through this catalog, we aim to promote the awareness of security architectural flaws and stimulate the security design thinking of developers, software engineers, and architects.

Smart Internet of Things (IoT) applications will rely on advanced IoT platforms that not only provide access to IoT sensors and actuators, but also provide access to cloud services and data analytics. Future IoT platforms should thus provide connectivity and intelligence. One approach to connecting IoT devices, IoT networks to cloud networks and services is to use network federation mechanisms over the internet to create network slices across heterogeneous platforms. Network slices also need to be protected from potential external and internal threats. In this paper we describe an approach for enforcing global security policies in the federated cloud and IoT networks. Our approach allows a global security to be defined in the form of a single service manifest and enforced across all federation network segments. It relies on network function virtualisation (NFV) and service function chaining (SFC) to enforce the security policy. The approach is illustrated with two case studies: one for a user that wishes to securely access IoT devices and another in which an IoT infrastructure administrator wishes to securely access some remote cloud and data analytics services.

Service composition is currently done by (hierarchical) orchestration and choreography. However, these approaches do not support explicit control flow and total compositionality, which are crucial for the scalability of service-oriented systems. In this paper, we propose exogenous connectors for service composition. These connectors support both explicit control flow and total compositionality in hierarchical service composition. To validate and evaluate our proposal, we present a case study based on the popular MusicCorp.

This paper introduces a newly developed Object-Oriented Open Software Architecture designed for supporting security applications, while leveraging on the capabilities offered by dedicated Open Hardware devices. Specifically, we target the SEcube™ platform, an Open Hardware security platform based on a 3D SiP (System on Package) designed and produced by Blu5 Group. The platform integrates three components employed for security in a single package: a Cortex-M4 CPU, a FPGA and an EAL5+ certified Smart Card. The Open Software Architecture targets both the host machine and the security device, together with the secure communication among them. To maximize its usability, this architecture is organized in several abstraction layers, ranging from hardware interfaces to device drivers, from security APIs to advanced applications, like secure messaging and data protection. We aim at releasing a multi-platform Open Source security framework, where software and hardware cooperate to hide to both the developer and the final users classical security concepts like cryptographic algorithms and keys, focusing, instead, on common operational security concepts like groups and policies.

Cloud Computing represents one of the most significant shifts in information technology and it enables to provide cloud-based security service such as Security-as-a-service (SECaaS). Improving of the cloud computing technologies, the traditional SIEM paradigm is able to shift to cloud-based security services. In this paper, we propose the SIEM architecture that can be deployed to the SECaaS platform which we have been developing for analyzing and recognizing intelligent cyber-threat based on virtualization technologies.

Current technologies to include cloud computing, social networking, mobile applications and crowd and synthetic intelligence, coupled with the explosion in storage and processing power, are evolving massive-scale marketplaces for a wide variety of resources and services. They are also enabling unprecedented forms and levels of collaborations among human and machine entities. In this new era, trust remains the keystone of success in any relationship between two or more parties. A primary challenge is to establish and manage trust in environments where massive numbers of consumers, providers and brokers are largely autonomous with vastly diverse requirements, capabilities, and trust profiles. Most contemporary trust management solutions are oblivious to diversities in trustors' requirements and contexts, utilize direct or indirect experiences as the only form of trust computations, employ hardcoded trust computations and marginally consider collaboration in trust management. We surmise the need for reference architecture for trust management to guide the development of a wide spectrum of trust management systems. In our previous work, we presented a preliminary reference architecture for trust management which provides customizable and reconfigurable trust management operations to accommodate varying levels of diversity and trust personalization. In this paper, we present a comprehensive taxonomy for trust management and extend our reference architecture to feature collaboration as a first-class object. Our goal is to promote the development of new collaborative trust management systems, where various trust management operations would involve collaborating entities. Using the proposed architecture, we implemented a collaborative personalized trust management system. Simulation results demonstrate the effectiveness and efficiency of our system.

Creating and implementing fault-tolerant distributed algorithms is a challenging task in highly safety-critical industries. Using formal methods supports design and development of complex algorithms. However, formal methods are often perceived as an unjustifiable overhead. This paper presents the experience and insights when using TLA+ and PlusCal to model and develop fault-tolerant and safety-critical modules for TAS Control Platform, a platform for railway control applications up to safety integrity level (SIL) 4. We show how formal methods helped us improve the correctness of the algorithms, improved development efficiency and how part of the gap between model and implementation has been closed by translation to C code. Additionally, we describe how we gained trust in the formal model and tools by following a specific design process called property-driven design, which also implicitly addresses software quality metrics such as code coverage metrics.

Summary form only given. Strong light-matter coupling has been recently successfully explored in the GHz and THz [1] range with on-chip platforms. New and intriguing quantum optical phenomena have been predicted in the ultrastrong coupling regime [2], when the coupling strength Ω becomes comparable to the unperturbed frequency of the system ω. We recently proposed a new experimental platform where we couple the inter-Landau level transition of an high-mobility 2DEG to the highly subwavelength photonic mode of an LC meta-atom [3] showing very large Ω/ωc = 0.87. Our system benefits from the collective enhancement of the light-matter coupling which comes from the scaling of the coupling Ω ∝ √n, were n is the number of optically active electrons. In our previous experiments [3] and in literature [4] this number varies from 104-103 electrons per meta-atom. We now engineer a new cavity, resonant at 290 GHz, with an extremely reduced effective mode surface Seff = 4 × 10-14 m2 (FE simulations, CST), yielding large field enhancements above 1500 and allowing to enter the few (\textbackslashtextless;100) electron regime. It consist of a complementary metasurface with two very sharp metallic tips separated by a 60 nm gap (Fig.1(a, b)) on top of a single triangular quantum well. THz-TDS transmission experiments as a function of the applied magnetic field reveal strong anticrossing of the cavity mode with linear cyclotron dispersion. Measurements for arrays of only 12 cavities are reported in Fig.1(c). On the top horizontal axis we report the number of electrons occupying the topmost Landau level as a function of the magnetic field. At the anticrossing field of B=0.73 T we measure approximately 60 electrons ultra strongly coupled (Ω/ω- \textbackslashtextbar\textbackslashtextbar

Access control is one of the most challenging issues in Cloud environment, it must ensure data confidentiality through enforced and flexible access policies. The revocation is an important task of the access control process, generally it consists on banishing some roles from the users. Attribute-based encryption is a promising cryptographic method which provides the fine-grained access, which makes it very useful in case of group sharing applications. This solution has initially been developed on a central authority model. Later, it has been extended to a multi-authority model which is more convenient and more reliable. However, the revocation problem is still the major challenge of this approach. There have been few proposed revocation solutions for the Multi-authority scheme and these solutions suffer from the lack of efficiency. In this paper, we propose an access control mechanism on a multi-authority architecture with an immediate and efficient attributes' or users' revocation. The proposed scheme uses decentralized CP-ABE to provide flexible and fine-grained access. Our solution provides collusion resistance, prevents security degradations, supports scalability and does not require keys' redistribution.

When clients interact with a cloud-based service, they expect certain levels of quality of service guarantees. These are expressed as security and privacy policies, interaction authorization policies, and service performance policies among others. The main security challenge in a cloud-based service environment, typically modeled using service-oriented architecture (SOA), is that it is difficult to trust all services in a service composition. In addition, the details of the services involved in an end-to-end service invocation chain are usually not exposed to the clients. The complexity of the SOA services and multi-tenancy in the cloud environment leads to a large attack surface. In this paper we propose a novel approach for end-to-end security and privacy in cloud-based service orchestrations, which uses a service activity monitor to audit activities of services in a domain. The service monitor intercepts interactions between a client and services, as well as among services, and provides a pluggable interface for different modules to analyze service interactions and make dynamic decisions based on security policies defined over the service domain. Experiments with a real-world service composition scenario demonstrate that the overhead of monitoring is acceptable for real-time operation of Web services.