4,236 research outputs found
Improved Kernel Security Through Code Validation, Diversification, and Minimization
The vast majority of hosts on the Internet, including mobile clients, are running one of three commodity, general-purpose operating system families. In such operating systems the kernel software executes at the highest processor privilege level. If an adversary is able to hijack the kernel software then by extension he has full control of the system. This control includes the ability to disable protection mechanisms and hide evidence of compromise.
The lack of diversity in commodity, general-purpose operating systems enables attackers to craft a single kernel exploit that has the potential to infect millions of hosts. If enough variants of the vulnerable software exist, then mass exploitation is much more difficult to achieve. We introduce novel kernel diversification techniques to improve kernel security.
Many modern kernels are self-patching; they modify themselves at run-time. Self-patching kernels must therefore allow kernel code to be modified at run-time. To prevent code injection attacks, some operating systems and security mechanisms enforce a W^X memory protection policy for kernel code. This protection policy prevents self-patching kernels from applying patches at run-time. We introduce a novel run-time kernel instruction-level validation technique to validate the integrity of patches at run-time.
Kernels shipped with general-purpose operating systems often contain extraneous code. The code may contain exploitable vulnerabilities or may be pieced together using return/jump-oriented programming to attack the system. Code-injection prevention techniques do not prevent such attacks. We introduce a novel run-time kernel minimization technique to improve kernel security.
We show that it is possible to strengthen the defenses of commodity general-purpose computer operating systems by increasing the diversity of, validating the integrity of, and ensuring the minimality of the included kernel components without modifying the kernel source code. Such protections can therefore be added to existing widely-used unmodified operating systems to prevent malicious software from executing in supervisor mode
Integrated Approaches to Digital-enabled Design for Manufacture and Assembly: A Modularity Perspective and Case Study of Huoshenshan Hospital in Wuhan, China
Countries are trying to expand their healthcare capacity through advanced construction, modular innovation, digital technologies and integrated design approaches such as Design for Manufacture and Assembly (DfMA). Within the context of China, there is a need for stronger implementation of digital technologies and DfMA, as well as a knowledge gap regarding how digital-enabled DfMA is implemented. More critically, an integrated approach is needed in addition to DfMA guidelines and digital-enabled approaches.
For this research, a mixed method was used. Questionnaires defined the context of Huoshenshan Hospital, namely the healthcare construction in China. Then, Huoshenshan Hospital provided a case study of the first emergency hospital which addressed the uncertainty of COVID-19. This extreme project, a 1,000-bed hospital built in 10 days, implemented DfMA in healthcare construction and provides an opportunity to examine the use of modularity. A workshop with a design institution provided basic facts and insight into past practice and was followed by interviews with 18 designers, from various design disciplines, who were involved in the project. Finally, multiple archival materials were used as secondary data sources.
It was found that complexity hinders building systems integration, while reinforcement relationships between multiple dimensions of modularity (across organisation-process-product-supply chain dimensions) are the underlying mechanism that allows for the reduction of complexity and the integration of building systems. Promoting integrated approaches to DfMA relies on adjusting and coupling multi-dimensional modular reinforcement relationships (namely, relationships of modular alignment, modular complement, and modular incentive). Thus, the building systems integrator can use these three approaches to increase the success of digital-enabled DfMA
Narratives about the Origin of COVID-19 on Twitter with an Emphasis on Conspiracy Theory
The primary idea of the following paper is to identify and analyze posts on Twitter about the origins of the coronavirus and the responses to the pandemics outbreak through the conspiracy theories that place China the communism and other international social and political players as the responsible for the creation and dissemination of the SARS-CoV-2 The theoretical contributions that will be discussed in due course resort to the understanding of conspiracy theories production and diffusion considered from a socio-anthropological perspective bringing into evidence the concept of conspiracy theor
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Enhancing Security by Diversifying Instruction Sets
Despite the variety of choices regarding hardware and software, to date a large number of computer systems remain identical. Characteristic examples of this trend are Windows on x86 and Android on ARM. This homogeneity, sometimes referred to as “computing oligoculture", provides a fertile ground for malware in the highly networked world of today. One way to counter this problem is to diversify systems so that attackers cannot quickly and easily compromise a large number of machines. For instance, if each system has a different ISA, the attacker has to invest more time in developing exploits that run on every system manifestation. It is not that each individual attack gets harder, but the spread of malware slows down. Further, if the diversified ISA is kept secret from the attacker, the bar for exploitation is raised even higher. In this paper, we show that system diversification can be realized by enabling diversity at the lowest hardware/software interface, the ISA, with almost zero performance overhead. We also describe how prac- tical development and deployment problems of diversified systems can be handled easily in the context of popular software distrbution models, such as the mobile app store model. We demonstrate our proposal with an OpenSPARC FPGA prototype
Professional English. Fundamentals of Software Engineering
Посібник містить оригінальні тексти фахового змісту, які супроводжуються термінологічним тематичним вокабуляром та вправами різного методичного спрямування.
Для студентів, які навчаються за напрямами підготовки: «Програмна інженерія», «Комп’ютерні науки» «Комп’ютерна інженерія»
Cybersecurity applications of Blockchain technologies
With the increase in connectivity, the popularization of cloud services, and the rise
of the Internet of Things (IoT), decentralized approaches for trust management
are gaining momentum. Since blockchain technologies provide a distributed ledger,
they are receiving massive attention from the research community in different application
fields. However, this technology does not provide cybersecurity by itself.
Thus, this thesis first aims to provide a comprehensive review of techniques and
elements that have been proposed to achieve cybersecurity in blockchain-based systems.
The analysis is intended to target area researchers, cybersecurity specialists
and blockchain developers. We present a series of lessons learned as well. One of
them is the rise of Ethereum as one of the most used technologies.
Furthermore, some intrinsic characteristics of the blockchain, like permanent
availability and immutability made it interesting for other ends, namely as covert
channels and malicious purposes.
On the one hand, the use of blockchains by malwares has not been characterized
yet. Therefore, this thesis also analyzes the current state of the art in this area. One
of the lessons learned is that covert communications have received little attention.
On the other hand, although previous works have analyzed the feasibility of
covert channels in a particular blockchain technology called Bitcoin, no previous
work has explored the use of Ethereum to establish a covert channel considering all
transaction fields and smart contracts.
To foster further defence-oriented research, two novel mechanisms are presented
on this thesis. First, Zephyrus takes advantage of all Ethereum fields and smartcontract
bytecode. Second, Smart-Zephyrus is built to complement Zephyrus by
leveraging smart contracts written in Solidity. We also assess the mechanisms feasibility
and cost. Our experiments show that Zephyrus, in the best case, can embed
40 Kbits in 0.57 s. for US 1.82 per bit), the provided stealthiness might be worth the price for attackers. Furthermore,
these two mechanisms can be combined to increase capacity and reduce
costs.Debido al aumento de la conectividad, la popularización de los servicios en la nube
y el auge del Internet de las cosas (IoT), los enfoques descentralizados para la
gestión de la confianza están cobrando impulso. Dado que las tecnologías de cadena
de bloques (blockchain) proporcionan un archivo distribuido, están recibiendo
una atención masiva por parte de la comunidad investigadora en diferentes campos
de aplicación. Sin embargo, esta tecnología no proporciona ciberseguridad por sí
misma. Por lo tanto, esta tesis tiene como primer objetivo proporcionar una revisión
exhaustiva de las técnicas y elementos que se han propuesto para lograr la ciberseguridad
en los sistemas basados en blockchain. Este análisis está dirigido a investigadores
del área, especialistas en ciberseguridad y desarrolladores de blockchain. A
su vez, se presentan una serie de lecciones aprendidas, siendo una de ellas el auge
de Ethereum como una de las tecnologías más utilizadas.
Asimismo, algunas características intrínsecas de la blockchain, como la disponibilidad
permanente y la inmutabilidad, la hacen interesante para otros fines, concretamente
como canal encubierto y con fines maliciosos.
Por una parte, aún no se ha caracterizado el uso de la blockchain por parte
de malwares. Por ello, esta tesis también analiza el actual estado del arte en este
ámbito. Una de las lecciones aprendidas al analizar los datos es que las comunicaciones
encubiertas han recibido poca atención.
Por otro lado, aunque trabajos anteriores han analizado la viabilidad de los
canales encubiertos en una tecnología blockchain concreta llamada Bitcoin, ningún
trabajo anterior ha explorado el uso de Ethereum para establecer un canal encubierto
considerando todos los campos de transacción y contratos inteligentes.
Con el objetivo de fomentar una mayor investigación orientada a la defensa,
en esta tesis se presentan dos mecanismos novedosos. En primer lugar, Zephyrus
aprovecha todos los campos de Ethereum y el bytecode de los contratos inteligentes.
En segundo lugar, Smart-Zephyrus complementa Zephyrus aprovechando los contratos inteligentes escritos en Solidity. Se evalúa, también, la viabilidad y el coste
de ambos mecanismos. Los resultados muestran que Zephyrus, en el mejor de los
casos, puede ocultar 40 Kbits en 0,57 s. por 1,64 US$, y recuperarlos en 2,8 s.
Smart-Zephyrus, por su parte, es capaz de ocultar un secreto de 4 Kb en 41 s. Si
bien es cierto que es caro (alrededor de 1,82 dólares por bit), el sigilo proporcionado
podría valer la pena para los atacantes. Además, estos dos mecanismos pueden
combinarse para aumentar la capacidad y reducir los costesPrograma de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: José Manuel Estévez Tapiador.- Secretario: Jorge Blasco Alís.- Vocal: Luis Hernández Encina
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