ECONOMICALLY PROTECTING COMPLEX, LEGACY OPERATING SYSTEMS USING SECURE DESIGN PRINCIPLES

In modern computer systems, complex legacy operating systems, such as Linux, are deployed ubiquitously. Many design choices in these legacy operating systems predate a modern understanding of security risks. As a result, new attack opportunities are routinely discovered to subvert such systems, which reveal design flaws that spur new research about secure design principles and other security mechanisms to thwart these attacks. Most research falls into two categories: encapsulating the threat and redesigning the system from scratch. Each approach has its challenge. Encapsulation can only limit the exposure to the risk, but not entirely prevent it. Rewriting the huge codebase of these operating systems is impractical in terms of developer effort, but appealing inasmuch as it can comprehensively eliminate security risks. This thesis pursues a third, understudied option: retrofitting security design principles in the existing kernel design. Conventional wisdom discourages retrofitting security because retrofitting is a hard problem, may require the use of new abstractions or break backward compatibility, may have unforeseen consequences, and may be equivalent to redesigning the system from scratch in terms of effort. This thesis offers new evidence to challenge this conventional wisdom, indicating that one can economically retrofit a comprehensive security policy onto complex, legacy systems. To demonstrate this assertion, this thesis firstly surveys the alternative of encapsulating the threat to the complex, legacy system by adding a monitoring layer using a technique called Virtual Machine Introspection, and discusses the shortcomings of this technique. Secondly, this thesis shows how to enforce the principle of least privilege by removing the need to run setuid-to-root binaries with administrator privilege. Finally, this thesis takes the first steps to show how to economically retrofit secure design principles to the OS virtualization feature of the Linux kernel called containers without rewriting the whole system. This approach can be applied more generally to other legacy systems.Doctor of Philosoph

Architecture de sécurité de bout en bout et mécanismes d'autoprotection pour les environnements Cloud

Since several years the virtualization of infrastructures became one of the major research challenges, consuming less energy while delivering new services. However, many attacks hinder the global adoption of Cloud computing. Self-protection has recently raised growing interest as possible element of answer to the cloud computing infrastructure protection challenge. Yet, previous solutions fall at the last hurdle as they overlook key features of the cloud, by lack of flexible security policies, cross-layered defense, multiple control granularities, and open security architectures. This thesis presents VESPA, a self-protection architecture for cloud infrastructures. Flexible coordination between self-protection loops allows enforcing a rich spectrum of security strategies. A multi-plane extensible architecture also enables simple integration of commodity security components.Recently, some of the most powerful attacks against cloud computing infrastructures target the Virtual Machine Monitor (VMM). In many case, the main attack vector is a poorly confined device driver. Current architectures offer no protection against such attacks. This thesis proposes an altogether different approach by presenting KungFuVisor, derived from VESPA, a framework to build self-defending hypervisors. The result is a very flexible self-protection architecture, enabling to enforce dynamically a rich spectrum of remediation actions over different parts of the VMM, also facilitating defense strategy administration. We showed the application to three different protection scheme: virus infection, mobile clouds and hypervisor drivers. Indeed VESPA can enhance cloud infrastructure securityLa virtualisation des infrastructures est devenue un des enjeux majeurs dans la recherche, qui fournissent des consommations d'énergie moindres et des nouvelles opportunités. Face à de multiples menaces et des mécanismes de défense hétérogènes, l'approche autonomique propose une gestion simplifiée, robuste et plus efficace de la sécurité du cloud. Aujourd'hui, les solutions existantes s'adaptent difficilement. Il manque des politiques de sécurité flexibles, une défense multi-niveaux, des contrôles à granularité variable, ou encore une architecture de sécurité ouverte. Ce mémoire présente VESPA, une architecture d'autoprotection pour les infrastructures cloud. VESPA est construit autour de politiques qui peuvent réguler la sécurité à plusieurs niveaux. La coordination flexible entre les boucles d'autoprotection réalise un large spectre de stratégies de sécurité comme des détections et des réactions sur plusieurs niveaux. Une architecture extensible multi plans permet d'intégrer simplement des éléments déjà présents. Depuis peu, les attaques les plus critiques contre les infrastructures cloud visent la brique la plus sensible: l'hyperviseur. Le vecteur d'attaque principal est un pilote de périphérique mal confiné. Les mécanismes de défense mis en jeu sont statiques et difficile à gérer. Nous proposons une approche différente avec KungFuVisor, un canevas logiciel pour créer des hyperviseurs autoprotégés spécialisant l'architecture VESPA. Nous avons montré son application à trois types de protection différents : les attaques virales, la gestion hétérogène multi-domaines et l'hyperviseur. Ainsi la sécurité des infrastructures cloud peut être améliorée grâce à VESP

Análise de malware com suporte de hardware

Orientadores: Paulo Lício de Geus, André Ricardo Abed GrégioDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: O mundo atual é impulsionado pelo uso de sistemas computacionais, estando estes pre- sentes em todos aspectos da vida cotidiana. Portanto, o correto funcionamento destes é essencial para se assegurar a manutenção das possibilidades trazidas pelos desenvolvi- mentos tecnológicos. Contudo, garantir o correto funcionamento destes não é uma tarefa fácil, dado que indivíduos mal-intencionados tentam constantemente subvertê-los visando benefíciar a si próprios ou a terceiros. Os tipos mais comuns de subversão são os ataques por códigos maliciosos (malware), capazes de dar a um atacante controle total sobre uma máquina. O combate à ameaça trazida por malware baseia-se na análise dos artefatos coletados de forma a permitir resposta aos incidentes ocorridos e o desenvolvimento de contramedidas futuras. No entanto, atacantes têm se especializado em burlar sistemas de análise e assim manter suas operações ativas. Para este propósito, faz-se uso de uma série de técnicas denominadas de "anti-análise", capazes de impedir a inspeção direta dos códigos maliciosos. Dentre essas técnicas, destaca-se a evasão do processo de análise, na qual são empregadas exemplares capazes de detectar a presença de um sistema de análise para então esconder seu comportamento malicioso. Exemplares evasivos têm sido cada vez mais utilizados em ataques e seu impacto sobre a segurança de sistemas é considerá- vel, dado que análises antes feitas de forma automática passaram a exigir a supervisão de analistas humanos em busca de sinais de evasão, aumentando assim o custo de se manter um sistema protegido. As formas mais comuns de detecção de um ambiente de análise se dão através da detecção de: (i) código injetado, usado pelo analista para inspecionar a aplicação; (ii) máquinas virtuais, usadas em ambientes de análise por questões de escala; (iii) efeitos colaterais de execução, geralmente causados por emuladores, também usados por analistas. Para lidar com malware evasivo, analistas tem se valido de técnicas ditas transparentes, isto é, que não requerem injeção de código nem causam efeitos colaterais de execução. Um modo de se obter transparência em um processo de análise é contar com suporte do hardware. Desta forma, este trabalho versa sobre a aplicação do suporte de hardware para fins de análise de ameaças evasivas. No decorrer deste texto, apresenta-se uma avaliação das tecnologias existentes de suporte de hardware, dentre as quais máqui- nas virtuais de hardware, suporte de BIOS e monitores de performance. A avaliação crítica de tais tecnologias oferece uma base de comparação entre diferentes casos de uso. Além disso, são enumeradas lacunas de desenvolvimento existentes atualmente. Mais que isso, uma destas lacunas é preenchida neste trabalho pela proposição da expansão do uso dos monitores de performance para fins de monitoração de malware. Mais especificamente, é proposto o uso do monitor BTS para fins de construção de um tracer e um debugger. O framework proposto e desenvolvido neste trabalho é capaz, ainda, de lidar com ataques do tipo ROP, um dos mais utilizados atualmente para exploração de vulnerabilidades. A avaliação da solução demonstra que não há a introdução de efeitos colaterais, o que per- mite análises de forma transparente. Beneficiando-se desta característica, demonstramos a análise de aplicações protegidas e a identificação de técnicas de evasãoAbstract: Today¿s world is driven by the usage of computer systems, which are present in all aspects of everyday life. Therefore, the correct working of these systems is essential to ensure the maintenance of the possibilities brought about by technological developments. However, ensuring the correct working of such systems is not an easy task, as many people attempt to subvert systems working for their own benefit. The most common kind of subversion against computer systems are malware attacks, which can make an attacker to gain com- plete machine control. The fight against this kind of threat is based on analysis procedures of the collected malicious artifacts, allowing the incident response and the development of future countermeasures. However, attackers have specialized in circumventing analysis systems and thus keeping their operations active. For this purpose, they employ a series of techniques called anti-analysis, able to prevent the inspection of their malicious codes. Among these techniques, I highlight the analysis procedure evasion, that is, the usage of samples able to detect the presence of an analysis solution and then hide their malicious behavior. Evasive examples have become popular, and their impact on systems security is considerable, since automatic analysis now requires human supervision in order to find evasion signs, which significantly raises the cost of maintaining a protected system. The most common ways for detecting an analysis environment are: i) Injected code detec- tion, since injection is used by analysts to inspect applications on their way; ii) Virtual machine detection, since they are used in analysis environments due to scalability issues; iii) Execution side effects detection, usually caused by emulators, also used by analysts. To handle evasive malware, analysts have relied on the so-called transparent techniques, that is, those which do not require code injection nor cause execution side effects. A way to achieve transparency in an analysis process is to rely on hardware support. In this way, this work covers the application of the hardware support for the evasive threats analysis purpose. In the course of this text, I present an assessment of existing hardware support technologies, including hardware virtual machines, BIOS support, performance monitors and PCI cards. My critical evaluation of such technologies provides basis for comparing different usage cases. In addition, I pinpoint development gaps that currently exists. More than that, I fill one of these gaps by proposing to expand the usage of performance monitors for malware monitoring purposes. More specifically, I propose the usage of the BTS monitor for the purpose of developing a tracer and a debugger. The proposed framework is also able of dealing with ROP attacks, one of the most common used technique for remote vulnerability exploitation. The framework evaluation shows no side-effect is introduced, thus allowing transparent analysis. Making use of this capability, I demonstrate how protected applications can be inspected and how evasion techniques can be identifiedMestradoCiência da ComputaçãoMestre em Ciência da ComputaçãoCAPE

Selective Dynamic Analysis of Virtualized Whole-System Guest Environments

Dynamic binary analysis is a prevalent and indispensable technique in program analysis. While several dynamic binary analysis tools and frameworks have been proposed, all suffer from one or more of: prohibitive performance degradation, a semantic gap between the analysis code and the execution under analysis, architecture/OS specificity, being user-mode only, and lacking flexibility and extendability. This dissertation describes the design of the Dynamic Executable Code Analysis Framework (DECAF), a virtual machine-based, multi-target, whole-system dynamic binary analysis framework. In short, DECAF seeks to address the shortcomings of existing whole-system dynamic analysis tools and extend the state of the art by utilizing a combination of novel techniques to provide rich analysis functionality without crippling amounts of execution overhead. DECAF extends the mature QEMU whole-system emulator, a type-2 hypervisor capable of emulating every instruction that executes within a complete guest system environment. DECAF provides a novel, hardware event-based method of just-in-time virtual machine introspection (VMI) to address the semantic gap problem. It also implements a novel instruction-level taint tracking engine at bitwise level of granularity, ensuring that taint propagation is sound and highly precise throughout the guest environment. A formal analysis of the taint propagation rules is provided to verify that most instructions introduce neither false positives nor false negatives. DECAF’s design also provides a plugin architecture with a simple-to-use, event-driven programming interface that makes it both flexible and extendable for a variety of analysis tasks. The implementation of DECAF consists of 9550 lines of C++ code and 10270 lines of C code. Its performance is evaluated using CPU2006 SPEC benchmarks, which show an average overhead of 605% for system wide tainting and 12% for VMI. Three platformneutral DECAF plugins - Instruction Tracer, Keylogger Detector, and API Tracer - are described and evaluated in this dissertation to demonstrate the ease of use and effectiveness of DECAF in writing cross-platform and system-wide analysis tools. This dissertation also presents the Virtual Device Fuzzer (VDF), a scalable fuzz testing framework for discovering bugs within the virtual devices implemented as part of QEMU. Such bugs could be used by malicious software executing within a guest under analysis by DECAF, so the discovery, reproduction, and diagnosis of such bugs helps to protect DECAF against attack while improving QEMU and any analysis platforms built upon QEMU. VDF uses selective instrumentation to perform targeted fuzz testing, which explores only the branches of execution belonging to virtual devices under analysis. By leveraging record and replay of memory-mapped I/O activity, VDF quickly cycles virtual devices through an arbitrarily large number of states without requiring a guest OS to be booted or present. Once a test case is discovered that triggers a bug, VDF reduces the test case to the minimum number of reads/writes required to trigger the bug and generates source code suitable for reproducing the bug during debugging and analysis. VDF is evaluated by fuzz testing eighteen QEMU virtual devices, generating 1014 crash or hang test cases that reveal bugs in six of the tested devices. Over 80% of the crashes and hangs were discovered within the first day of testing. VDF covered an average of 62.32% of virtual device branches during testing, and the average test case was minimized to a reproduction test case only 18.57% of its original size

Demystifying Internet of Things Security

Break down the misconceptions of the Internet of Things by examining the different security building blocks available in Intel Architecture (IA) based IoT platforms. This open access book reviews the threat pyramid, secure boot, chain of trust, and the SW stack leading up to defense-in-depth. The IoT presents unique challenges in implementing security and Intel has both CPU and Isolated Security Engine capabilities to simplify it. This book explores the challenges to secure these devices to make them immune to different threats originating from within and outside the network. The requirements and robustness rules to protect the assets vary greatly and there is no single blanket solution approach to implement security. Demystifying Internet of Things Security provides clarity to industry professionals and provides and overview of different security solutions What You'll Learn Secure devices, immunizing them against different threats originating from inside and outside the network Gather an overview of the different security building blocks available in Intel Architecture (IA) based IoT platforms Understand the threat pyramid, secure boot, chain of trust, and the software stack leading up to defense-in-depth Who This Book Is For Strategists, developers, architects, and managers in the embedded and Internet of Things (IoT) space trying to understand and implement the security in the IoT devices/platforms

Measuring the Semantic Integrity of a Process Self

The focus of the thesis is the definition of a framework to protect a process from attacks against the process self, i.e. attacks that alter the expected behavior of the process, by integrating static analysis and run-time monitoring. The static analysis of the program returns a description of the process self that consists of a context-free grammar, which defines the legal system call traces, and a set of invariants on process variables that hold when a system call is issued. Run-time monitoring assures the semantic integrity of the process by checking that its behavior is coherent with the process self returned by the static analysis. The proposed framework can also cover kernel integrity to protect the process from attacks from the kernel-level. The implementation of the run-time monitoring is based upon introspection, a technique that analyzes the state of a computer to rebuild and check the consistency of kernel or user-level data structures. The ability of observing the run-time values of variables reduces the complexity of the static analysis and increases the amount of information that can be extracted on the run-time behavior of the process. To achieve transparency of the controls for the process while avoiding the introduction of special purpose hardware units that access the memory, the architecture of the run-time monitoring adopts virtualization technology and introduces two virtual machines, the monitored and the introspection virtual machines. This approach increases the overall robustness because a distinct virtual machine, the introspection virtual machine, applies introspection in a transparent way both to verify the kernel integrity and to retrieve the status of the process to check the process self. After presenting the framework and its implementation, the thesis discusses some of its applications to increase the security of a computer network. The first application of the proposed framework is the remote attestation of the semantic integrity of a process. Then, the thesis describes a set of extensions to the framework to protect a process from physical attacks by running an obfuscated version of the process code. Finally, the thesis generalizes the framework to support the efficient sharing of an information infrastructure among users and applications with distinct security and reliability requirements by introducing highly parallel overlays