In this thesis, we address the problem faced by modern operating systems due to the exploitation of Hardware-Assisted Full-Virtualization technology by attackers. Virtualization technology has been of growing importance these days. With the help of such a technology, multiple operating systems can be run on a single piece of hardware, with little or no modification to the operating system. Both Intel and AMD have contributed to x86 full-virtualization through their respective instruction set architectures. Hardware virtualization extensions can be found in almost all x86 processors these days. Hardware virtualization technologies have opened a whole new frontier for a new kind of attack. A system hacker can abuse hardware virualization technology to gain control over an operating system on-the-fly (i.e., without a system restart) by installing a thin Virtual Machine Monitor (VMM) below the native operating system. Such a VMM based malware is termed a Hardware-Assisted Virtual Machine (HVM) rootkit. We discuss the technique used by a rootkit named Blue Pill to subvert the Windows Vista operating system by exploiting the AMD-V (codenamed "Pacifica") virtualization extensions. HVM rootkits do not hook any operating system code or data regions; hence detecting the existence of such malware using conventional techniques becomes extremely difficult. This thesis discusses existing methods to detect such rootkits and their inefficiencies. In this work, we implement a proof-of-concept HVM rootkit using Intel-VT hardware virtualization technology and also discuss how such an attack can be defended against by using an autonomic architecture called SHARK, which was proposed by Vikas et al., in MICRO 2008.

Interpretation of Java bytecode results in slow execution of program.First version of Java Virtual Machine(JVM) implementation was relied on interpretation techniques. On the other hand performance can be improved by translating the Java bytecode into machine code by a Just-In-Time(JIT) compiler and this technique is being integrated into most JVM implementations. Java is an automatic garbage collected language, freeing the programmer from the explicit memory management. Garbage collection "pause" time can be reduced by using a generational garbage collection. This thesis describes an implementation of a JVM. The specific contributions made in this thesis include: development of a Just-In-Time(JIT) compiler using DAG construction technique, a bytecode interpreter, a generational garbage collector. Our implementation can execute Java bytecode either by an interpreter or the bytecode can be translated into machine code using the JIT compiler and the translated code is directly executed by the processor. We have implemented the Java Native Interface (JNI) to enable using C and assembly language programs with Java.

<p>This thesis presents the different ways that have been achieved to improve and widen the interaction possibilities between LiveLab users. LiveLab is a virtual laboratory used at IDA (Institutionen för datavetenskap / The Department of Computer and Information Sciences) at Linköpings Universitet. This virtual laboratory is a virtual machine running an Kubuntu Linux 1 distribution thanks to VMware ² Player. It was created at the HCS (Human-Centered Systems) division of IDA. Aiming to be used in more and more courses, LiveLab may present a lack of certain functionalities. Thus thesis tries to shows how the development of applications may fulfil this lack.</p>

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As computer systems support more aspects of modern life, from finance to health care, security is becoming increasingly important. However, building secure systems remains a challenge. Software continues to have security vulnerabilities due to reasons ranging from programmer errors to inadequate programming tools. Because of these vulnerabilities we need mechanisms that protect sensitive data even when the software is untrusted. This dissertation shows that secure and practical frameworks can be built for protecting users' data from untrusted applications in both desktop and cloud computing environment. Laminar is a new framework that secures desktop applications by enforcing policies written as information flow rules. Information flow control, a form of mandatory access control, enables programmers to write powerful, end-to-end security guarantees while reducing the amount of trusted code. Current programming abstractions and implementations of this model either compromise end-to-end security guarantees or require substantial modifications to applications, thus deterring adoption. Laminar addresses these shortcomings by exporting a single set of abstractions to control information flows through operating system resources and heap-allocated objects. Programmers express security policies by labeling data and represent access restrictions on code using a new abstraction called a security region. The Laminar programming model eases incremental deployment, limits dynamic security checks, and supports multithreaded programs that can access heterogeneously labeled data. In large scale, distributed computations safeguarding information requires solutions beyond mandatory access control. An important challenge is to ensure that the computation, including its output, does not leak sensitive information about the inputs. For untrusted code, access control cannot guarantee that the output does not leak information. This dissertation proposes Airavat, a MapReduce-based system which augments mandatory access control with differential privacy to guarantee security and privacy for distributed computations. Data providers control the security policy for their sensitive data, including a mathematical bound on potential privacy violations. Users without security expertise can perform computations on the data; Airavat prevents information leakage beyond the data provider's policy. Our prototype implementation of Airavat demonstrates that several data mining tasks can be performed in a privacy preserving fashion with modest performance overheads. / text

Current computing infrastructures use virtualization to increase resource utilization by deploying multiple virtual machines on the same hardware. Virtualization is particularly attractive for data center, cloud computing, and hosting services; in these environments computer systems are typically configured to have fast processors, large physical memory and huge storage capable of supporting concurrent execution of virtual machines. Subsequently, this high demand for resources is directly translating into higher energy consumption and monetary costs. Increasingly managing energy consumption of virtual machines is becoming critical. However, virtual machines make the energy management more challenging because a layer of virtualization separates hardware from the guest operating system executing inside a virtual machine. This dissertation addresses the challenge of designing energy-efficient storage, memory and buffer cache for virtual machines by exploring innovative mechanisms as well as existing approaches. We analyze the architecture of an open-source virtual machine platform Xen and address energy management on each subsystem. For storage system, we study the I/O behavior of the virtual machine systems. We address the isolation between virtual machine monitor and virtual machines, and increase the burstiness of disk accesses to improve energy efficiency. In addition, we propose a transparent energy management on main memory for any types of guest operating systems running inside virtual machines. Furthermore, we design a dedicated mechanism for the buffer cache based on the fact that data-intensive applications heavily rely on a large buffer cache that occupies a majority of physical memory. We also propose a novel hybrid mechanism that is able to improve energy efficiency for any memory access. All the mechanisms achieve significant energy savings while lowering the impact on performance for virtual machines.

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The evolution of cloud computing allows the provisioning of IT resources over the Internet and promises many benefits for both - the service users and providers. Despite various benefits offered by cloud based services, many users hesitate in moving their IT systems to the cloud mainly due to many new security problems introduced by cloud environments. In fact, the characteristics of cloud computing become basis of new problems, for example, support of third party hosting introduces loss of user control on the hardware; similarly, on-demand availability requires reliance on complex and possibly insecure API interfaces; seamless scalability relies on the use of sub-providers; global access over public Internet exposes to broader attack surface; and use of shared resources for better resource utilization introduces isolation problems in a multi-tenant environment. These new security issues in addition to existing security challenges (that exist in today's classic IT environments) become major reasons for the lack of user trust in cloud based services categorized in Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) or Infrastructure-as-a-Service (IaaS). The focus of this thesis is on IaaS model which allows users to lease IT resources (e.g. computing power, memory, storage, etc.) from a public cloud to create Virtual Machine (VM) instances. The public cloud deployment model considered in this thesis exhibits most elasticity (i.e. degree of freedom to lease/release IT resources according to user demand) but is least secure as compared to private or hybrid models. As a result, public clouds are not trusted for many use cases which involve processing of security critical data such as health records, financial data, government data, etc. However, public IaaS clouds can also be made trustworthy and viable for these use cases by providing better transparency and security assurance services for the user. In this thesis, we consider such assurance services and identify security aspects which are important for making public clouds trustworthy. Based upon our findings, we propose solutions which promise to improve cloud transparency thereby realizing trustworthy clouds. The solutions presented in this thesis mainly deal with the secure life cycle management of the user VM which include protocols and their implementation for secure VM launch and migration. The VM launch and migration solutions ensure that the user VM is always hosted on correct cloud platforms which are setup according to a profile that fulfills the use case relevant security requirements. This is done by using an automated platform security audit and certification mechanism which uses trusted computing and security automation techniques in an integrated solution. In addition to provide the assurance about the cloud platforms, we also propose a solution which provides assurance about the placement of user data in correct and approved geographical locations which is critical from many legal aspects and usually an important requirement of the user. Finally, the assurance solutions provided in this thesis increase cloud transparency which is important for user trust and to realize trustworthy clouds.

No description available.

abstract: This research describes software based remote attestation schemes for obtaining the integrity of an executing user application and the Operating System (OS) text section of an untrusted client platform. A trusted external entity issues a challenge to the client platform. The challenge is executable code which the client must execute, and the code generates results which are sent to the external entity. These results provide the external entity an assurance as to whether the client application and the OS are in pristine condition. This work also presents a technique where it can be verified that the application which was attested, did not get replaced by a different application after completion of the attestation. The implementation of these three techniques was achieved entirely in software and is backward compatible with legacy machines on the Intel x86 architecture. This research also presents two approaches to incorporating software based "root of trust" using Virtual Machine Monitors (VMMs). The first approach determines the integrity of an executing Guest OS from the Host OS using Linux Kernel-based Virtual Machine (KVM) and qemu emulation software. The second approach implements a small VMM called MIvmm that can be utilized as a trusted codebase to build security applications such as those implemented in this research. MIvmm was conceptualized and implemented without using any existing codebase; its minimal size allows it to be trustworthy. Both the VMM approaches leverage processor support for virtualization in the Intel x86 architecture. / Dissertation/Thesis / Ph.D. Computer Science 2011