Trusted Computing and Secure Virtualization in Cloud Computing

Large-scale deployment and use of cloud computing in industry is accompanied and in the same time hampered by concerns regarding protection of data handled by cloud computing providers. One of the consequences of moving data processing and storage off company premises is that organizations have less control over their infrastructure. As a result, cloud service (CS) clients must trust that the CS provider is able to protect their data and infrastructure from both external and internal attacks. Currently however, such trust can only rely on organizational processes declared by the CS provider and can not be remotely verified and validated by an external party. Enabling the CS client to verify the integrity of the host where the virtual machine instance will run, as well as to ensure that the virtual machine image has not been tampered with, are some steps towards building trust in the CS provider. Having the tools to perform such verifications prior to the launch of the VM instance allows the CS clients to decide in runtime whether certain data should be stored- or calculations should be made on the VM instance offered by the CS provider. This thesis combines three components -- trusted computing, virtualization technology and cloud computing platforms -- to address issues of trust and security in public cloud computing environments. Of the three components, virtualization technology has had the longest evolution and is a cornerstone for the realization of cloud computing. Trusted computing is a recent industry initiative that aims to implement the root of trust in a hardware component, the trusted platform module. The initiative has been formalized in a set of specifications and is currently at version 1.2. Cloud computing platforms pool virtualized computing, storage and network resources in order to serve a large number of customers customers that use a multi-tenant multiplexing model to offer on-demand self-service over broad network. Open source cloud computing platforms are, similar to trusted computing, a fairly recent technology in active development. The issue of trust in public cloud environments is addressed by examining the state of the art within cloud computing security and subsequently addressing the issues of establishing trust in the launch of a generic virtual machine in a public cloud environment. As a result, the thesis proposes a trusted launch protocol that allows CS clients to verify and ensure the integrity of the VM instance at launch time, as well as the integrity of the host where the VM instance is launched. The protocol relies on the use of Trusted Platform Module (TPM) for key generation and data protection. The TPM also plays an essential part in the integrity attestation of the VM instance host. Along with a theoretical, platform-agnostic protocol, the thesis also describes a detailed implementation design of the protocol using the OpenStack cloud computing platform. In order the verify the implementability of the proposed protocol, a prototype implementation has built using a distributed deployment of OpenStack. While the protocol covers only the trusted launch procedure using generic virtual machine images, it presents a step aimed to contribute towards the creation of a secure and trusted public cloud computing environment

FINE-GRAINED ACCESS CONTROL ON ANDROID COMPONENT

The pervasiveness of Android devices in today’s interconnected world emphasizes the importance of mobile security in protecting user privacy and digital assets. Android’s current security model primarily enforces application-level mechanisms, which fail to address component-level (e.g., Activity, Service, and Content Provider) security concerns. Consequently, third-party code may exploit an application’s permissions, and security features like MDM or BYOD face limitations in their implementation. To address these concerns, we propose a novel Android component context-aware access control mechanism that enforces layered security at multiple Exception Levels (ELs), including EL0, EL1, and EL3. This approach effectively restricts component privileges and controls resource access as needed. Our solution comprises Flasa at EL0, extending SELinux policies for inter-component interactions and SQLite content control; Compac, spanning EL0 and EL1, which enforces component-level permission controls through Android runtime and kernel modifications; and TzNfc, leveraging TrustZone technologies to secure third-party services and limit system privileges via Trusted Execution Environment (TEE). Our evaluations demonstrate the effectiveness of our proposed solution in containing component privileges, controlling inter-component interactions and protecting component level resource access. This enhanced solution, complementing Android’s existing security architecture, provides a more comprehensive approach to Android security, benefiting users, developers, and the broader mobile ecosystem

TEE-based distributed watchtowers for fraud protection in the Lightning Network

The Lightning Network is a payment channel network built on top of the cryptocurrency Bitcoin. It allows Bitcoin to scale by performing transactions off-chain to reduce load on the blockchain. Malicious payment channel participants can try to commit fraud by closing channels with outdated balances. The Lightning Network allows resolving this dispute on the blockchain. However, this mechanism forces the channels\u27 participants to watch the blockchain in regular intervals. It has been proposed to offload this monitoring duty to a third party, called a watchtower. However, existing approaches for watchtowers do not scale as they have storage requirements linear in the number of updates in a channel. In this work, we propose TEE Guard, a new architecture for watchtowers that leverages the features of Trusted Execution Environments to build watchtowers that require only constant memory and are thus able to scale. We show that TEE Guard is deployable because it can run with the existing Bitcoin and Lightning Network protocols. We also show that it is economically viable for a third party to provide watchtower services. As a watchtower needs to be trusted to be watching the blockchain, we also introduce a mechanism that allows customers to verify that a watchtower has been running continuously

TEE-based distributed watchtowers for fraud protection in the Lightning Network

The Lightning Network is a payment channel network built on top of the cryptocurrency Bitcoin. It allows Bitcoin to scale by performing transactions off-chain to reduce load on the blockchain. Malicious payment channel participants can try to commit fraud by closing channels with outdated balances. The Lightning Network allows resolving this dispute on the blockchain. However, this mechanism forces the channels\u27 participants to watch the blockchain in regular intervals. It has been proposed to offload this monitoring duty to a third party, called a watchtower. However, existing approaches for watchtowers do not scale as they have storage requirements linear in the number of updates in a channel. In this work, we propose TEE Guard, a new architecture for watchtowers that leverages the features of Trusted Execution Environments to build watchtowers that require only constant memory and are thus able to scale. We show that TEE Guard is deployable because it can run with the existing Bitcoin and Lightning Network protocols. We also show that it is economically viable for a third party to provide watchtower services. As a watchtower needs to be trusted to be watching the blockchain, we also introduce a mechanism that allows customers to verify that a watchtower has been running continuously

TCG based approach for secure management of virtualized platforms: state-of-the-art

There is a strong trend shift in the favor of adopting virtualization to get business benefits. The provisioning of virtualized enterprise resources is one kind of many possible scenarios. Where virtualization promises clear advantages it also poses new security challenges which need to be addressed to gain stakeholders confidence in the dynamics of new environment. One important facet of these challenges is establishing 'Trust' which is a basic primitive for any viable business model. The Trusted computing group (TCG) offers technologies and mechanisms required to establish this trust in the target platforms. Moreover, TCG technologies enable protecting of sensitive data in rest and transit. This report explores the applicability of relevant TCG concepts to virtualize enterprise resources securely for provisioning, establish trust in the target platforms and securely manage these virtualized Trusted Platforms

Trusted Launch of Virtual Machine Instances in Public IaaS Environments

Cloud computing and Infrastructure-as-a-Service (IaaS) are emerging and promising technologies, however their adoption is hampered by data security concerns. At the same time, Trusted Computing (TC) is experiencing an increasing interest as a security mechanism for IaaS. In this paper we present a protocol to ensure the launch of a virtual machine (VM) instance on a trusted remote compute host. Relying on Trusted Platform Module operations such as binding and sealing to provide integrity guarantees for clients that require a trusted VM launch, we have designed a trusted launch protocol for VM instances in public IaaS environments. We also present a proof-of-concept implementation of the protocol based on OpenStack, an open-source IaaS platform. The results provide a basis for the use of TC mechanisms within IaaS platforms and pave the way for a wider applicability of TC to IaaS security

Secure Management of Personal Health Records by Applying Attribute-Based Encryption

The confidentiality of personal health records is a major problem when patients use commercial Web-based systems to store their health data. Traditional access control mechanisms, such as Role-Based Access Control, have several limitations with respect to enforcing access control policies and ensuring data confidentiality. In particular, the data has to be stored on a central server locked by the access control mechanism, and the data owner loses control on the data from the moment when the data is sent to the requester. Therefore, these mechanisms do not fulfil the requirements of data outsourcing scenarios where the third party storing the data should not have access to the plain data, and it is not trusted to enforce access control policies. In this paper, we describe a new approach which enables secure storage and controlled sharing of patient’s health records in the aforementioned scenarios. A new variant of a ciphertext-policy attribute-based encryption scheme is proposed to enforce patient/organizational access control policies such that everyone can download the encrypted data but only authorized users from the social domain (e.g. family, friends, or fellow patients) or authorized users from the professional\ud domain (e.g. doctors or nurses) are allowed to decrypt it