Building and evaluating an inconspicuous smartphone authentication method

Tese de mestrado em Engenharia Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013Os smartphones que trazemos connosco estão cada vez mais entranhados nas nossas vidas intimas. Estes dispositivos possibilitam novas formas de trabalhar, de socializar, e ate de nos divertirmos. No entanto, também criaram novos riscos a nossa privacidade. Uma forma comum de mitigar estes riscos e configurar o dispositivo para bloquear apos um período de inatividade. Para voltar a utiliza-lo, e então necessário superar uma barreira de autenticação. Desta forma, se o aparelho cair das mãos de outra pessoa, esta não poderá utiliza-lo de forma a que tal constitua uma ameaça. O desbloqueio com autenticação e, assim, o mecanismo que comummente guarda a privacidade dos utilizadores de smartphones. Porem, os métodos de autenticação atualmente utilizados são maioritariamente um legado dos computadores de mesa. As palavras-passe e códigos de identificação pessoal são tornados menos seguros pelo facto de as pessoas criarem mecanismos para os memorizarem mais facilmente. Alem disso, introduzir estes códigos e inconveniente, especialmente no contexto móvel, em que as interações tendem a ser curtas e a necessidade de autenticação atrapalha a prossecução de outras tarefas. Recentemente, os smartphones Android passaram a oferecer outro método de autenticação, que ganhou um grau de adoção assinalável. Neste método, o código secreto do utilizador e uma sucessão de traços desenhados sobre uma grelha de 3 por 3 pontos apresentada no ecrã táctil. Contudo, quer os códigos textuais/numéricos, quer os padrões Android, são suscetíveis a ataques rudimentares. Em ambos os casos, o canal de entrada e o toque no ecrã táctil; e o canal de saída e o visual. Tal permite que outras pessoas possam observar diretamente a introdução da chave; ou que mais tarde consigam distinguir as marcas deixadas pelos dedos na superfície de toque. Alem disso, estes métodos não são acessíveis a algumas classes de utilizadores, nomeadamente os cegos. Nesta dissertação propõe-se que os métodos de autenticação em smartphones podem ser melhor adaptados ao contexto móvel. Nomeadamente, que a possibilidade de interagir com o dispositivo de forma inconspícua poderá oferecer aos utilizadores um maior grau de controlo e a capacidade de se auto-protegerem contra a observação do seu código secreto. Nesse sentido, foi identificada uma modalidade de entrada que não requer o canal visual: sucessões de toques independentes de localização no ecrã táctil. Estes padrões podem assemelhar-se (mas não estão limitados) a ritmos ou código Morse. A primeira contribuição deste trabalho e uma técnica algorítmica para a deteção destas sucessões de toques, ou frases de toque, como chaves de autenticação. Este reconhecedor requer apenas uma demonstração para configuração, o que o distingue de outras abordagens que necessitam de vários exemplos para treinar o algoritmo. O reconhecedor foi avaliado e demonstrou ser preciso e computacionalmente eficiente. Esta contribuição foi enriquecida com o desenvolvimento de uma aplicação Android que demonstra o conceito. A segunda contribuição e uma exploração de fatores humanos envolvidos no uso de frases de toque para autenticação. E consubstanciada em três estudos com utilizadores, em que o método de autenticação proposto e comparado com as alternativas mais comuns: PIN e o padrão Android. O primeiro estudo (N=30) compara os três métodos no que que diz respeito a resistência a observação e à usabilidade, entendida num sentido lato, que inclui a experiencia de utilização (UX). Os resultados sugerem que a usabilidade das três abordagens e comparável, e que em condições de observação perfeitas, nos três casos existe grande viabilidade de sucesso para um atacante. O segundo estudo (N=19) compara novamente os três métodos mas, desta feita, num cenário de autenticação inconspícua. Com efeito, os participantes tentaram introduzir os códigos com o dispositivo situado por baixo de uma mesa, fora do alcance visual. Neste caso, demonstra-se que a autenticação com frases de toque continua a ser usável. Já com as restantes alternativas existe uma diminuição substancial das medidas de usabilidade. Tal sugere que a autenticação por frases de toque suporta a capacidade de interação inconspícua, criando assim a possibilidade de os utilizadores se protegerem contra possíveis atacantes. O terceiro estudo (N=16) e uma avaliação de usabilidade e aceitação do método de autenticação com utilizadores cegos. Neste estudo, são também elicitadas estratégias de ocultação suportadas pela autenticação por frases de toque. Os resultados sugerem que a técnica e também adequada a estes utilizadores.As our intimate lives become more tangled with the smartphones we carry, privacy has become an increasing concern. A widely available option to mitigate security risks is to set a device so that it locks after a period of inactivity, requiring users to authenticate for subsequent use. Current methods for establishing one's identity are known to be susceptible to even rudimentary observation attacks. The mobile context in which interactions with smartphones are prone to occur further facilitates shoulder-surfing. We submit that smartphone authentication methods can be better adapted to the mobile context. Namely, the ability to interact with the device in an inconspicuous manner could offer users more control and the ability to self-protect against observation. Tapping is a communication modality between a user and a device that can be appropriated for that purpose. This work presents a technique for employing sequences of taps, or tap phrases, as authentication codes. An efficient and accurate tap phrase recognizer, that does not require training, is presented. Three user studies were conducted to compare this approach to the current leading methods. Results indicate that the tapping method remains usable even under inconspicuous authentications scenarios. Furthermore, we found that it is appropriate for blind users, to whom usability barriers and security risks are of special concern

Revisiting graphical passwords for augmenting, not replacing, text passwords

Users generally choose weak passwords which can be easily guessed. On the other hand, adoption of alternatives to text passwords has been slow due to cost and usability factors. We acknowledge that incumbent passwords remain difficult to beat and introduce in this study Type&Click (T&C), a hybrid scheme supporting text passwords with the graphical passwords. In T&C, users first type a text as usual and then make a single click on an image to complete the password entry. While largely preserving the login experience with the text passwords, the new scheme utilizes accumulated scientific knowledge in graphical password research (implicit feedback, persuasion during password creation, leveraging cued recall memory). The results of our user study suggest that T&C is promising for augmenting text passwords for improved security without degrading usability. Copyright 2013 ACM

Web-based Secure Application Control

The world wide web today serves as a distributed application platform. Its origins, however, go back to a simple delivery network for static hypertexts. The legacy from these days can still be observed in the communication protocol used by increasingly sophisticated clients and applications. This thesis identifies the actual security requirements of modern web applications and shows that HTTP does not fit them: user and application authentication, message integrity and confidentiality, control-flow integrity, and application-to-application authorization. We explore the other protocols in the web stack and work out why they can not fill the gap. Our analysis shows that the underlying problem is the connectionless property of HTTP. However, history shows that a fresh start with web communication is far from realistic. As a consequence, we come up with approaches that contribute to meet the identified requirements. We first present impersonation attack vectors that begin before the actual user authentication, i.e. when secure web interaction and authentication seem to be unnecessary. Session fixation attacks exploit a responsibility mismatch between the web developer and the used web application framework. We describe and compare three countermeasures on different implementation levels: on the source code level, on the framework level, and on the network level as a reverse proxy. Then, we explain how the authentication credentials that are transmitted for the user login, i.e. the password, and for session tracking, i.e. the session cookie, can be complemented by browser-stored and user-based secrets respectively. This way, an attacker can not hijack user accounts only by phishing the user's password because an additional browser-based secret is required for login. Also, the class of well-known session hijacking attacks is mitigated because a secret only known by the user must be provided in order to perform critical actions. In the next step, we explore alternative approaches to static authentication credentials. Our approach implements a trusted UI and a mutually authenticated session using signatures as a means to authenticate requests. This way, it establishes a trusted path between the user and the web application without exchanging reusable authentication credentials. As a downside, this approach requires support on the client side and on the server side in order to provide maximum protection. Another approach avoids client-side support but can not implement a trusted UI and is thus susceptible to phishing and clickjacking attacks. Our approaches described so far increase the security level of all web communication at all time. This is why we investigate adaptive security policies that fit the actual risk instead of permanently restricting all kinds of communication including non-critical requests. We develop a smart browser extension that detects when the user is authenticated on a website meaning that she can be impersonated because all requests carry her identity proof. Uncritical communication, however, is released from restrictions to enable all intended web features. Finally, we focus on attacks targeting a web application's control-flow integrity. We explain them thoroughly, check whether current web application frameworks provide means for protection, and implement two approaches to protect web applications: The first approach is an extension for a web application framework and provides protection based on its configuration by checking all requests for policy conformity. The second approach generates its own policies ad hoc based on the observed web traffic and assuming that regular users only click on links and buttons and fill forms but do not craft requests to protected resources.Das heutige World Wide Web ist eine verteilte Plattform für Anwendungen aller Art: von einfachen Webseiten über Online Banking, E-Mail, multimediale Unterhaltung bis hin zu intelligenten vernetzten Häusern und Städten. Seine Ursprünge liegen allerdings in einem einfachen Netzwerk zur Übermittlung statischer Inhalte auf der Basis von Hypertexten. Diese Ursprünge lassen sich noch immer im verwendeten Kommunikationsprotokoll HTTP identifizieren. In dieser Arbeit untersuchen wir die Sicherheitsanforderungen moderner Web-Anwendungen und zeigen, dass HTTP diese Anforderungen nicht erfüllen kann. Zu diesen Anforderungen gehören die Authentifikation von Benutzern und Anwendungen, die Integrität und Vertraulichkeit von Nachrichten, Kontrollflussintegrität und die gegenseitige Autorisierung von Anwendungen. Wir untersuchen die Web-Protokolle auf den unteren Netzwerk-Schichten und zeigen, dass auch sie nicht die Sicherheitsanforderungen erfüllen können. Unsere Analyse zeigt, dass das grundlegende Problem in der Verbindungslosigkeit von HTTP zu finden ist. Allerdings hat die Geschichte gezeigt, dass ein Neustart mit einem verbesserten Protokoll keine Option für ein gewachsenes System wie das World Wide Web ist. Aus diesem Grund beschäftigt sich diese Arbeit mit unseren Beiträgen zu sicherer Web-Kommunikation auf der Basis des existierenden verbindungslosen HTTP. Wir beginnen mit der Beschreibung von Session Fixation-Angriffen, die bereits vor der eigentlichen Anmeldung des Benutzers an der Web-Anwendung beginnen und im Erfolgsfall die temporäre Übernahme des Benutzerkontos erlauben. Wir präsentieren drei Gegenmaßnahmen, die je nach Eingriffsmöglichkeiten in die Web-Anwendung umgesetzt werden können. Als nächstes gehen wir auf das Problem ein, dass Zugangsdaten im WWW sowohl zwischen den Teilnehmern zu Authentifikationszwecken kommuniziert werden als auch für jeden, der Kenntnis dieser Daten erlangt, wiederverwendbar sind. Unsere Ansätze binden das Benutzerpasswort an ein im Browser gespeichertes Authentifikationsmerkmal und das sog. Session-Cookie an ein Geheimnis, das nur dem Benutzer und der Web-Anwendung bekannt ist. Auf diese Weise kann ein Angreifer weder ein gestohlenes Passwort noch ein Session-Cookie allein zum Zugriff auf das Benutzerkonto verwenden. Darauffolgend beschreiben wir ein Authentifikationsprotokoll, das vollständig auf die Übermittlung geheimer Zugangsdaten verzichtet. Unser Ansatz implementiert eine vertrauenswürdige Benutzeroberfläche und wirkt so gegen die Manipulation derselben in herkömmlichen Browsern. Während die bisherigen Ansätze die Sicherheit jeglicher Web-Kommunikation erhöhen, widmen wir uns der Frage, inwiefern ein intelligenter Browser den Benutzer - wenn nötig - vor Angriffen bewahren kann und - wenn möglich - eine ungehinderte Kommunikation ermöglichen kann. Damit trägt unser Ansatz zur Akzeptanz von Sicherheitslösungen bei, die ansonsten regelmäßig als lästige Einschränkungen empfunden werden. Schließlich legen wir den Fokus auf die Kontrollflussintegrität von Web-Anwendungen. Bösartige Benutzer können den Zustand von Anwendungen durch speziell präparierte Folgen von Anfragen in ihrem Sinne manipulieren. Unsere Ansätze filtern Benutzeranfragen, die von der Anwendung nicht erwartet wurden, und lassen nur solche Anfragen passieren, die von der Anwendung ordnungsgemäß verarbeitet werden können

Modelling escalation of attacks in federated identity management

PhD ThesisFederated Identity Management (FIM) is an increasingly prevalent method for authenticating users online. FIM offloads the authentication burden from a Service Provider (SP) to an Identity Provider (IdP) that the SP trusts. The different entities involved in the FIM process are referred to as stakeholders. The benefits of FIM to stakeholders are clear, such as the ability for users to use Single Sign-On. However, the security of FIM also has to be evaluated. Attacks on one point in a FIM system can lead to other attacks being possible, and detecting those attacks can be hard just from modelling the functionality of the FIM system. Attacks in which the effect of one attack can become the cause for another attack are referred to in this thesis as escalating attacks. The overall research question this thesis revolves around: how can we model escalating attacks to detect attacks which are possible through an adversary first launching another attack, and present causality of attacks to the FIM stakeholders involved? This thesis performs a survey of existing attacks in FIM. We categorise attacks on FIM using a taxonomy of our own design. This survey is the first attempt at categorising attacks that target FIM using a taxonomy. Some attacks can have an effect that causes another attack to be possible in ways that are difficult to predict. We consider a case study involving OAuth 2.0 (provided by existing literature), as a basis for modelling attack escalation. We then seek to present a language for modelling FIM systems and attacker manipulations on those systems. We find that FIM systems can be generalised for the purpose of a programmatic logical analysis. In addition, attacker manipulations on a system can be broken down using an existing conceptual framework called Malicious and Accidental Fault Tolerance (MAFTIA). Using a generalised FIM system model and MAFTIA, we can express a complex interlinking of attacks informed by case studies in FIM security analysis. This is the first attempt to model FIM systems generally and apply logical analysis to that model. Finally, we show how causality of attacks can be analysed using attack trees. We find that any solutions to an escalating attack can be expressed using a tree model which conforms to existing research on attack trees. Our approach is the first attempt of modelling attacks on FIM systems through the use of attack trees. We consider stakeholder attribution and cost analysis as concrete methods for analysing attack trees

Moving usable security research out of the lab: evaluating the use of VR studies for real-world authentication research

Empirical evaluations of real-world research artefacts that derive results from observations and experiments are a core aspect of usable security research. Expert interviews as part of this thesis revealed that the costs associated with developing and maintaining physical research artefacts often amplify human-centred usability and security research challenges. On top of that, ethical and legal barriers often make usability and security research in the field infeasible. Researchers have begun simulating real-life conditions in the lab to contribute to ecological validity. However, studies of this type are still restricted to what can be replicated in physical laboratory settings. Furthermore, historically, user study subjects were mainly recruited from local areas only when evaluating hardware prototypes. The human-centred research communities have recognised and partially addressed these challenges using online studies such as surveys that allow for the recruitment of large and diverse samples as well as learning about user behaviour. However, human-centred security research involving hardware prototypes is often concerned with human factors and their impact on the prototypes’ usability and security, which cannot be studied using traditional online surveys. To work towards addressing the current challenges and facilitating research in this space, this thesis explores if – and how – virtual reality (VR) studies can be used for real-world usability and security research. It first validates the feasibility and then demonstrates the use of VR studies for human-centred usability and security research through six empirical studies, including remote and lab VR studies as well as video prototypes as part of online surveys. It was found that VR-based usability and security evaluations of authentication prototypes, where users provide touch, mid-air, and eye-gaze input, greatly match the findings from the original real-world evaluations. This thesis further investigated the effectiveness of VR studies by exploring three core topics in the authentication domain: First, the challenges around in-the-wild shoulder surfing studies were addressed. Two novel VR shoulder surfing methods were implemented to contribute towards realistic shoulder surfing research and explore the use of VR studies for security evaluations. This was found to allow researchers to provide a bridge over the methodological gap between lab and field studies. Second, the ethical and legal barriers when conducting in situ usability research on authentication systems were addressed. It was found that VR studies can represent plausible authentication environments and that a prototype’s in situ usability evaluation results deviate from traditional lab evaluations. Finally, this thesis contributes a novel evaluation method to remotely study interactive VR replicas of real-world prototypes, allowing researchers to move experiments that involve hardware prototypes out of physical laboratories and potentially increase a sample’s diversity and size. The thesis concludes by discussing the implications of using VR studies for prototype usability and security evaluations. It lays the foundation for establishing VR studies as a powerful, well-evaluated research method and unfolds its methodological advantages and disadvantages

SecMVC : a model for secure software design based on the model-view-controller pattern

Current advances in the software development industry are growing more ubiquitous by the day. This has caused for security, not only in the broader sense, but specifically within the design and overall development of software itself, to become all the more important. An evidently prevalent problem in the domain of software development is that software security is not consistently addressed during design, which undermines core security concerns, and leads to the development of insecure software. This research seeks to address this issue via a model for secure software design, which is based on a software design pattern, namely, the Model-View-Controller (MVC) pattern. The use of a pattern to convey knowledge is not a new notion. However, the ability of software design patterns to convey secure software design is an idea worth investigating. Following identification of secure software design principles and concepts, as well as software design patterns, specifically those relating to the MVC pattern, a model was designed and developed. With the MVC pattern argued as being a suitable foundation for the model, the security conscious MVC (SecMVC) combines secure software design principles and concepts into the MVC pattern. Together herewith, the MVC pattern’s components in the MVC Compound pattern, namely: the Observer pattern, the Strategy pattern, and the Composite pattern, have provided further sub-models for less abstraction and greater detail. These sub-models were developed, as a result of the SecMVC model’s evaluation in the validation for this study, an expert review. Argued in the light of similar research methods, the expert review was chosen – along with a process that included the use of two expert participants to validate the SecMVC model. It was determined through the expert review that the SecMVC model is of sufficient utility, quality, and efficacy to constitute research value. The research methodology process followed was design science, in which the SecMVC model, which includes its related sub-models, serves as the artefact and research output of this study. This research study contributes evidence of the feasibility for integrating knowledge into software design patterns. This includes the SecMVC model itself. In addition, it argues for the use of an expert review, as an evaluative research method for such an artifact

Law and Policy for the Quantum Age

Law and Policy for the Quantum Age is for readers interested in the political and business strategies underlying quantum sensing, computing, and communication. This work explains how these quantum technologies work, future national defense and legal landscapes for nations interested in strategic advantage, and paths to profit for companies