23 research outputs found

    Host card emulation with tokenisation: Security risk assessments

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    Host Card Emulation (HCE) é uma arquitetura que possibilita a representação virtual (emulação) de cartões contactless, permitindo a realização de transações através dispositivos móveis com capacidade de realizar comunicações via Near-Field Communication (NFC), sem a necessidade de utilização de um microprocessador chip, Secure Element (SE), utilizado em pagamentos NFC anteriores ao HCE. No HCE, a emulação do cartão é efetuada essencialmente através de software, geralmente em aplicações do tipo wallet. No modelo de HCE com Tokenização (HCEt), que ´e o modelo HCE específico analisado nesta dissertação, a aplicação armazena tokens de pagamento, que são chaves criptográficas derivadas das chaves do cartão original, críticas, por permitirem a execução de transações, ainda que, com limitações na sua utilização. No entanto, com a migração de um ambiente resistente a violações (SE) para um ambiente não controlado (uma aplicação num dispositivo móvel), há vários riscos que devem ser avaliados adequadamente para que seja possível materializar uma implementação baseada no risco. O presente estudo descreve o modelo de HCE com Tokenização (HCEt) e identifica e avalia os seus riscos, analisando o modelo do ponto de vista de uma aplicação wallet num dispositivo móvel, que armazena tokens de pagamento para poder realizar transações contactless

    On the security of mobile sensors

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    PhD ThesisThe age of sensor technology is upon us. Sensor-rich mobile devices are ubiquitous. Smart-phones, tablets, and wearables are increasingly equipped with sensors such as GPS, accelerometer, Near Field Communication (NFC), and ambient sensors. Data provided by such sensors, combined with the fast-growing computational capabilities on mobile platforms, offer richer and more personalised apps. However, these sensors introduce new security challenges to the users, and make sensor management more complicated. In this PhD thesis, we contribute to the field of mobile sensor security by investigating a wide spectrum of open problems in this field covering attacks and defences, standardisation and industrial approaches, and human dimensions. We study the problems in detail and propose solutions. First, we propose “Tap-Tap and Pay” (TTP), a sensor-based protocol to prevent the Mafia attack in NFC payment. The Mafia attack is a special type of Man-In-The-Middle attack which charges the user for something more expensive than what she intends to pay by relaying transactions to a remote payment terminal. In TTP, a user initiates the payment by physically tapping her mobile phone against the reader. We observe that this tapping causes transient vibrations at both devices which are measurable by the embedded accelerometers. Our observations indicate that these sensor measurements are closely correlated within the same tapping, and different if obtained from different tapping events. By comparing the similarity between the two measurements, the bank can distinguish the Mafia fraud apart from a legitimate NFC transaction. The experimental results and the user feedback suggest the practical feasibility of TTP. As compared with previous sensor-based solutions, ours is the only one that works even when the attacker and the user are in nearby locations or share similar ambient environments. Second, we demonstrate an in-app attack based on a real world problem in contactless payment known as the card collision or card clash. A card collision happens when more than one card (or NFC-enabled device) are presented to the payment terminal’s field, and the terminal does not know which card to choose. By performing experiments, we observe that the implementation of contactless terminals in practice matches neither EMV nor ISO standards (the two primary standards for smart card payment) on card collision. Based on this inconsistency, we propose “NFC Payment Spy”, a malicious app that tracks the user’s contactless payment transactions. This app, running on a smart phone, simulates a card which requests the payment information (amount, time, etc.) from the terminal. When the phone and the card are both presented to a contactless terminal (given that many people use mobile case wallets to travel light and keep wallet essentials close to hand), our app can effectively win the race condition over the card. This attack is the first privacy attack on contactless payments based on the problem of card collision. By showing the feasibility of this attack, we raise awareness of privacy and security issues in contactless payment protocols and implementation, specifically in the presence of new technologies for payment such as mobile platforms. Third, we show that, apart from attacking mobile devices by having access to the sensors through native apps, we can also perform sensor-based attacks via mobile browsers. We examine multiple browsers on Android and iOS platforms and study their policies in granting permissions to JavaScript code with respect to access to motion and orientation sensor data. Based on our observations, we identify multiple vulnerabilities, and propose “TouchSignatures” and “PINLogger.js”, two novel attacks in which malicious JavaScript code listens to such sensor data measurements. We demonstrate that, despite the much lower sampling rate (comparing to a native app), a remote attacker is able to learn sensitive user information such as physical activities, phone call timing, touch actions (tap, scroll, hold, zoom), and PINs based on these sensor data. This is the first report of such a JavaScript-based attack. We disclosed the above vulnerability to the community and major mobile browser vendors classified the problem as high-risk and fixed it accordingly. Finally, we investigate human dimensions in the problem of sensor management. Although different types of attacks via sensors have been known for many years, the problem of data leakage caused by sensors has remained unsolved. While working with W3C and browser vendors to fix the identified problem, we came to appreciate the complexity of this problem in practice and the challenge of balancing security, usability, and functionality. We believe a major reason for this is that users are not fully aware of these sensors and the associated risks to their privacy and security. Therefore, we study user understanding of mobile sensors, specifically their risk perceptions. This is the only research to date that studies risk perceptions for a comprehensive list of mobile sensors (25 in total). We interview multiple participants from a range of backgrounds by providing them with multiple self-declared questionnaires. The results indicate that people in general do not have a good understanding of the complexities of these sensors; hence making security judgements about these sensors is not easy for them. We discuss how this observation, along with other factors, renders many academic and industry solutions ineffective. This makes the security and privacy issues of mobile sensors and other sensorenabled technologies an important topic to be investigated further

    Host Card Emulation with Tokenisation: Security Risk Assessment

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    Host Card Emulation (HCE) is an architecture that provides virtual representation of contactless cards, enabling transactional communication for mobile devices with Near-Field Communication (NFC) support without the need of Secure Element (SE) hardware. Performing the card emulation mainly by software, usually in wallet-like applications which store payment tokens for enabling transactions, creates several risks that need to be properly evaluated in order to be able to materialise a risk-based implementation. This paper describes the HCEt and proposes the identification and assessment of its risks through a survey conducted to specialists in the subject matter, analysing the model from the point of view of a wallet application on a mobile device that stores payment tokens to be able to perform contactless transactions. Despite the increasing complexity and specialisation of software, hardware, and the respective technical cyberattacks we conclude that the human nature remains the easiest to exploit, with greater gains

    Mobile Payment and Digital Wallet Financial Services (2021)

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    TWallet ARM TrustZone Enabled Trustable Mobile Wallet: A Case for Cryptocurrency Wallets

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    With the increasing popularity of Blockchains supporting virtual cryptocurrencies it has become more important to have secure devices supporting operations in trustable cryp- tocurrency wallets. These wallets, currently implemented as mobile Apps or components of mobile Apps must be protected from possible intrusion attacks. ARM TrustZone technology has made available an extension of the ARM processor ar- chitecture, allowing for the isolation of trusted and non-trusted execution environments. Critical components and their runtime support can be "booted" and loaded to run in the isolated execution environment, backed by the ARM processor. The ARM TrustZone solution provides the possible enforcement of security and privacy conditions for applica- tions, ensuring the containment of sensitive software components and data-management facilities, isolating them from OS-level intrusion attacks. The idea is that sensitive compo- nents and managed data are executed with a trust computing base supported at hardware and firmware levels, not affected by intrusions against non-protected OS-level runtime components. In this dissertation we propose TWallet: a solution designed as a generic model to sup- port secure and trustable Mobile Client Wallets (implemented as mobile Apps), backed by the ARM TrustZone technology. The objective is to manage local sensitive stored data and processing components in a trust execution environment isolated from the Android OS. We believe that the proposed TWallet framework model can also inspire other specific solutions that can benefit from the isolation of sensitive components in mobile Android Apps. As a proof-of-concept, we used the TWallet framework model to implement a trusted wallet application used as an Ethereum wallet, to operate with the Ethereum Blockchain. To achieve our goals, we also conducted different experimental observations to analyze and validate the solution, with the implemented wallet integrated, tested and validated with the Rinkeby Ethereum Test Network.Com o aumento da popularidade de Blockchains e utilização de sistemas de criptomoedas, tornou-se cada vez mais importante a utilização de dispositivos seguros para suportar aplicações de carteiras móveis (vulgarmente conhecidas por mobile wallets ou mobile cryptowallets). Estas aplicações permitem aos utilizadores uma gestão local, cómoda, confiável e segura de dados e operações integradas com sistemas de Blockchains. Estas carteiras digitais, como aplicações móveis completas ou como componentes de outras aplicações, têm sido desenvolvidas de forma generalizada para diferentes sistemas operativos convencionais, nomeadamente para o sistema operativo Android e para diferentes sistemas de criptomoedas. As wallets devem permitir processar e armazenar informação sensível associada ao controlo das operações realizadas, incluindo gestão e consulta de saldos de criptomoedas, realização e consultas de históricos de movimentos de transações ou consolidação do estado destas operações integradas com as Blockchains remotas. Devem também garantir o controlo seguro e confiável do processamento criptográfico envolvido, bem como a segurança das respetivas chaves criptográficas utilizadas. A Tecnologia ARM TrustZone disponibiliza um conjunto de extensões para as arquiteturas de processadores ARM, possibilitando o isolamento e execução de código num ambiente de execução suportado ao nível do hardware do próprio processador ARM. Isto possibilita que componentes críticos de aplicações ou de sistemas operativos suportados em processadores ARM, possam executar em ambientes isolados com minimização propiciada pelo isolamento da sua Base de Computação Confiável (ou Trusted Computing Base). A execução em ambiente seguro suportado pela solução TrustZone pode oferecer assim um reforço adicional de propriedades de confiabilidade, segurança e privacidade. Isto possibilita isolar componentes e dados críticos de possíveis ataques ou intrusões ao nível do processamento e gestão de memória ou armazenamento suportados pelo sistema operativo ou bibliotecas middleware, como é usual no caso de aplicações móveis, executando em ambiente Android OS ou noutros sistemas operativos de dispositivos móveis. Nesta dissertação propomos a solução TWallet, uma aproximação genérica para suporte de wallets utilizadas como aplicações móveis confiáveis em ambiente Android OS e fortalecidas pela utilização da tecnologia ARM TrustZone. O objetivo é possibilitar o isolamento de dados e componentes sensíveis deste tipo de aplicações, tornando-as mais seguras e confiáveis. Acreditamos que o modelo de desenho e implementação da solução TWallet, visto como uma framework de referência, poderá também ser utilizada no desenvolvimento de outras aplicações móveis em que o isolamento e segurança de componentes e dados críticos são requisitos semelhantes aos endereçados. Este pode ser o caso de aplicações de pagamento móvel, aplicações bancárias na área de mobile banking ou aplicações de bilhética na área vulgarmente chamada como mobile e-ticketing, entre outras. Como prova de conceito, utilizámos a TWallet framework para implementar um protótipo de uma wallet confiável, suportável em Android OS, para gestão de operações e criptomoedas na Blockchain Ethereum. A implementação foi integrada, testada e validada na rede Rinkeby Test Network - uma rede de desenvolvimento e testes utilizada como primeiro estágio de validação de aplicações e componentes para a rede Ethereum em operação real. Para validação da solução TWallet foi realizada uma avaliação experimen- tal. Esta avaliação envolveu a observação de indicadores de operação com verificação e comparação de diferentes métricas de operação e desempenho, bem como de alocação de recursos da aplicação protegida no modelo TWallet, comparando esses mesmo indicadores com o caso da mesma aplicação sem essa proteção

    Attacks On Near Field Communication Devices

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    For some years, Near Field Communication (NFC) has been a popularly known technology characterized by its short-distance wireless communication, mainly used in providing different agreeable services such as payment with mobile phones in stores, Electronic Identification, Transportation Electronic Ticketing, Patient Monitoring, and Healthcare. The ability to quickly connect devices offers a level of secure communication. That notwithstanding, looking deeply at NFC and its security level, identifying threats leading to attacks that can alter the user’s confidentiality and data privacy becomes obvious. This paper summarizes some of these attacks, emphasizing four main attack vectors, bringing out a taxonomy of these attack vectors on NFC, and presenting security issues alongside privacy threats within the application environment

    Mobile financial services in Ghana - Measures for achieving safety and security of services

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    Thesis submitted to the Department of Computer Science, Ashesi University College, in partial fulfillment of Bachelor of Science degree in Management Information Systems, April 2017The use of mobile phones has become part of the daily activities of about ninety percent of Ghanaian adults. This has contributed to the rapid adoption of mobile financial services by Ghanaians. In 2014, Bank of Ghana reported over two million registered users. Africa and the rest of the world have also experienced this exponential growth in the use of mobile financial services. Due to the huge money it is raising in that sector, fraudsters have made several attempts on these systems leading to the loss of enormous sums of money. The objective of this study is to understand the mobile financial service ecosystem in Ghana and internationally, assess what risks users may face and suggest measures to help prevent or reduce the effects of these risks. In order to better understand the concept of mobile financial service, some academic papers were reviewed revealing the components of the ecosystem, risks that these players may face and some proposed solutions by scholars. Case studies, in-depth interviews and secondary data were gathered for this research. Findings from the data collected show that some risks users may face include: malware infection of devices or point of sale terminals, corruption of information stored on the server of acquirers or service providers, theft of data during transaction, including man-in-the middle attacks, advanced persistent thefts and insecure data connectivity. Also some mitigation measures to these threats include enforcement of two factor authentication on systems, securing data connections using Secured Socket Layer (SSL) authentication, secure configuration, hardening of critical servers and data encryption during transactions. This study is limited geographically because the interviews held included players in the mobile financial service ecosystem in Accra only. Also only three companies were interviewed for this study due to the limited time constraint.Ashesi University Colleg

    Challenges and opportunities of mobile payments innovations

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    Innovation in financial services is a major trend on the sector and the payments industry is no exception to that. New ways of paying, as mobile payments, are emerging and changing the payments market. Non-financial institutions are entering the market through the provision of mobile payments, threatening the dominant position banks hold in the industry. This thesis aim is to analyze mobile payments as a service innovation, primarily through the spectrum of banks as old incumbents in this market. To understand the traits and main characteristics of these products, as well as how innovation in mobile payments is changing or even creating a new market. The results of the study suggest that we are facing a radical innovation, according to the Gallouj and Weinstein (1997) modes and models of innovation, as there is a completely new system behind mobile payments services. This innovation is assuming different forms and is still hard to infer if mobile payments are creating a new market, as these kind of services are still majorly seen by experts in the area, who were interviewed for this study, as a complement to other ways of paying, regardless of being a complete new system with different competences needed for operating. With regard to the new and different providers of these services operating in the market, it was found that they can be segmented into three clusters with different characteristics: Banks, which are the traditional incumbents of this market; Mobile Network Operators & Manufacturers, which are extremely focused on technology and data; Others, which include companies from other sectors, fintechs or other startups, characterized by being very innovative and flexible. These new services come with new market dynamics involving companies that traditionally were not associated with the provision of financial services, and threatening the relevance banks used to have in the payments industry.A inovação nos serviços financeiros é uma tendência geral do sector e a área dos pagamentos não é exceção. A área financeira dos pagamentos tem sofrido enormes mudanças, o que está a ter implicações nos mercados financeiros, e em particular nos serviços de pagamentos. Várias instituições não financeiras estão a entrar no mercado através da criação de novos serviços de pagamentos móveis, ameaçando a posição dominante que os bancos possuíam na área. Esta tese tem como objetivo analisar os pagamentos móveis enquanto uma inovação em serviços, focando principalmente a perspetiva dos bancos que tradicionalmente possuíam uma posição dominante neste mercado. A tese pretende entender e discutir as principais características destes produtos inovadores de pagamentos móveis, bem como se estes novos serviços estão a mudar ou mesmo a criar um novo mercado. Os resultados deste estudo sugerem que estamos perante uma inovação radical, pois de acordo com os modos e modelos de inovação de Gallouj e Weinstein (1997), os serviços de pagamentos móveis são um novo sistema de pagamentos. Esta inovação tem assumido diferentes formas, havendo ainda um elevado grau de ambiguidade quanto à sua capacidade de geração de um novo mercado, já que este tipo de serviços são considerados por especialistas da área, que foram entrevistados no âmbito deste estudo, como um complemento a outros métodos de pagamento. Isto, apesar de se tratar de um sistema novo com diferentes competências necessárias à sua execução e utilização. O estudo conclui que os fornecedores destes serviços podem ser segmentados em três clusters com diferentes características: Bancos, os tradicionais incumbentes deste mercado; Fabricantes e Operadores de redes móveis, que são extremamente focados em tecnologia e data; Outros, incluindo empresas de outros sectores, fintechs e outras start-ups, caracterizados por serem extremamente inovadores e flexíveis. O estudo evidência que estes novos serviços de pagamentos trazem novas dinâmicas ao mercado envolvendo empresas que tradicionalmente não estariam associados à prestação de serviços financeiros, o que ameaça a relevância dos bancos no sector dos pagamentos
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