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183
Efficient TCB Reduction and Attestation
, 2009
"... We develop a special-purpose hypervisor called TrustVisor that facilitates the execution of security-sensitive code in isolation from commodity OSes and applications. TrustVisor provides code and execution integrity as well as data secrecy and integrity for protected code, even in the presence of a ..."
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Cited by 141 (17 self)
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We develop a special-purpose hypervisor called TrustVisor that facilitates the execution of security-sensitive code in isolation from commodity OSes and applications. TrustVisor provides code and execution integrity as well as data secrecy and integrity for protected code, even in the presence of a compromised OS. These strong properties can be attested to a remote verifier. TrustVisor only adds 5306 lines to the TCB (over half of which is for cryptographic operations). TrustVisorimposeslessthan7%overheadinthecommoncase. Thisoverheadislargelytheresult of today’s x86hardware virtualization support. 1
HyperSafe: A lightweight approach to provide lifetime hypervisor control-flow integrity
- In Proceedings of the 31st IEEE Symposium on Security and Privacy
, 2010
"... Abstract — Virtualization is being widely adopted in today’s computing systems. Its unique security advantages in isolating and introspecting commodity OSes as virtual machines (VMs) have enabled a wide spectrum of applications. However, a common, fundamental assumption is the presence of a trustwor ..."
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Cited by 91 (6 self)
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Abstract — Virtualization is being widely adopted in today’s computing systems. Its unique security advantages in isolating and introspecting commodity OSes as virtual machines (VMs) have enabled a wide spectrum of applications. However, a common, fundamental assumption is the presence of a trustworthy hypervisor. Unfortunately, the large code base of commodity hypervisors and recent successful hypervisor attacks (e.g., VM escape) seriously question the validity of this assumption. In this paper, we present HyperSafe, a lightweight approach that endows existing Type-I bare-metal hypervisors with a unique self-protection capability to provide lifetime controlflow integrity. Specifically, we propose two key techniques. The first one – non-bypassable memory lockdown – reliably protects the hypervisor’s code and static data from being compromised even in the presence of exploitable memory corruption bugs (e.g., buffer overflows), therefore successfully providing hypervisor code integrity. The second one – restricted pointer indexing – introduces one layer of indirection to convert the control data into pointer indexes. These pointer indexes are restricted such that the corresponding call/return targets strictly follow the hypervisor control flow graph, hence expanding protection to control-flow integrity. We have built a prototype and used it to protect two open-source Type-I hypervisors: BitVisor and Xen. The experimental results with synthetic hypervisor exploits and benchmarking programs show HyperSafe can reliably enable the hypervisor self-protection and provide the integrity guarantee with a small performance overhead. I.
CloudVisor: Retrofitting protection of virtual machines in multi-tenant cloud with nested virtualization
- IN PROC. OF ACM SOSP, CAS CAIS, PORTUGAL,
, 2011
"... Multi-tenant cloud, which usually leases resources in the form of virtual machines, has been commercially available for years. Unfortunately, with the adoption of commodity virtualized infrastructures, software stacks in typical multi-tenant clouds are non-trivially large and complex, and thus are p ..."
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Cited by 77 (2 self)
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Multi-tenant cloud, which usually leases resources in the form of virtual machines, has been commercially available for years. Unfortunately, with the adoption of commodity virtualized infrastructures, software stacks in typical multi-tenant clouds are non-trivially large and complex, and thus are prone to compromise or abuse from adversaries including the cloud operators, which may lead to leakage of security-sensitive data. In this paper, we propose a transparent, backward-compatible approach that protects the privacy and integrity of customers ’ virtual machines on commodity virtualized infrastructures, even facing a total compromise of the virtual machine monitor (VMM) and the management VM. The key of our approach is the separation of the resource management from security protection in the virtualization layer. A tiny security monitor is introduced underneath the commodity VMM using nested virtualization and provides protection to the hosted VMs. As a result, our approach allows virtualization software (e.g., VMM, management VM and tools) to handle complex tasks of managing leased VMs for the cloud, without breaking security of users ’ data inside the VMs. We have implemented a prototype by leveraging commercially-available hardware support for virtualization. The prototype system, called CloudVisor, comprises only 5.5K LOCs and supports the Xen VMM with multiple Linux and Windows as the guest OSes. Performance evaluation shows that CloudVisor incurs moderate slowdown for I/O intensive applications and very small slowdown for other applications.
HyperSentry: Enabling Stealthy In-context Measurement of Hypervisor Integrity ∗
"... This paper presents HyperSentry, a novel framework to enable integrity measurement of a running hypervisor (or any other highest privileged software layer on a system). Unlike existing solutions for protecting privileged software, Hyper-Sentry does not introduce a higher privileged software layer be ..."
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Cited by 58 (1 self)
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This paper presents HyperSentry, a novel framework to enable integrity measurement of a running hypervisor (or any other highest privileged software layer on a system). Unlike existing solutions for protecting privileged software, Hyper-Sentry does not introduce a higher privileged software layer below the integrity measurement target, which could start another race with malicious attackers in obtaining the highest privilege in the system. Instead, HyperSentry introduces a software component that is properly isolated from the hypervisor to enable stealthy and in-context measurement of the runtime integrity of the hypervisor. While stealthiness is necessary to ensure that a compromised hypervisor does not have a chance to hide the attack traces upon detecting an up-coming measurement, in-context measurement is necessary to retrieve all the needed inputs for a successful integrity measurement. HyperSentry uses an out-of-band channel (e.g., Intelligent Platform Management Interface (IPMI), which is commonly available on server platforms) to trigger the stealthy measurement, and adopts the System Management Mode (SMM) to protect its base code and critical data. A key contribution of HyperSentry is the set of novel techniques that overcome SMM’s limitation, providing an integrity measurement agent with (1) the same contextual information available to the hypervisor, (2) completely protected execution, and (3) attestation to its output. To evaluate HyperSentry,
Bootstrapping trust in commodity computers.
- In IEEE Symposium on Security and Privacy (S&P),
, 2010
"... Abstract Trusting a computer for a security-sensitive task (such as checking email or banking online) requires the user to know something about the computer's state. We examine research on securely capturing a computer's state, and consider the utility of this information both for improvi ..."
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Cited by 48 (5 self)
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Abstract Trusting a computer for a security-sensitive task (such as checking email or banking online) requires the user to know something about the computer's state. We examine research on securely capturing a computer's state, and consider the utility of this information both for improving security on the local computer (e.g., to convince the user that her computer is not infected with malware) and for communicating a remote computer's state (e.g., to enable the user to check that a web server will adequately protect her data). Although the recent "Trusted Computing" initiative has drawn both positive and negative attention to this area, we consider the older and broader topic of bootstrapping trust in a computer. We cover issues ranging from the wide collection of secure hardware that can serve as a foundation for trust, to the usability issues that arise when trying to convey computer state information to humans. This approach unifies disparate research efforts and highlights opportunities for additional work that can guide real-world improvements in computer security.
Trustworthy and Personalized Computing on Public Kiosks
"... Many people desire ubiquitous access to their personal computing environments. We present a system in which a user leverages a personal mobile device to establish trust in a public computing device, or kiosk, prior to resuming her environment on the kiosk. We have designed a protocol by which the mo ..."
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Cited by 41 (0 self)
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Many people desire ubiquitous access to their personal computing environments. We present a system in which a user leverages a personal mobile device to establish trust in a public computing device, or kiosk, prior to resuming her environment on the kiosk. We have designed a protocol by which the mobile device determines the identity and integrity of all software loaded on the kiosk, in order to inform the user whether the kiosk is trustworthy. Our system exploits emerging hardware security technologies, namely the Trusted Platform Module and new support in x86 processors for establishing a dynamic root of trust. We have demonstrated the viability of our approach by implementing and evaluating our system on commodity hardware. Through a brief survey, we found that respondents are generally willing to endure a delay in exchange for an increased assurance of data privacy, and that the delay incurred by our unoptimized prototype is close to the range tolerable to the respondents. We have focused on allowing the user to personalize a kiosk by running her own virtual machine there. However, our work is generally applicable to establishing trust on public computing devices before revealing any sensitive information to those devices.
ObliviStore: High performance oblivious cloud storage
"... Abstract. We design and build ObliviStore, a high performance, distributed ORAM-based cloud data store secure in the malicious model. To the best of our knowledge, ObliviStore is the fastest ORAM implementation known to date, and is faster by 10X or more in comparison with the best known ORAM implem ..."
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Cited by 37 (10 self)
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Abstract. We design and build ObliviStore, a high performance, distributed ORAM-based cloud data store secure in the malicious model. To the best of our knowledge, ObliviStore is the fastest ORAM implementation known to date, and is faster by 10X or more in comparison with the best known ORAM implementation. ObliviStore achieves high throughput by making I/O operations asynchronous. Asynchrony introduces security challenges, i.e., we must prevent information leakage not only through access patterns, but also through timing of I/O events. We propose various practical optimizations which are key to achieving high performance, as well as techniques for a data center to dynamically scale up a distributed ORAM. We show that with 11 trusted machines (each with a modern CPU), and 20 Solid State Drives, ObliviStore achieves a throughput of 31.5MB/s with a block size of 4KB. I.
Not-a-Bot: Improving Service Availability in the Face of Botnet Attacks
"... A large fraction of email spam, distributed denial-ofservice (DDoS) attacks, and click-fraud on web advertisements are caused by traffic sent from compromised machines that form botnets. This paper posits that by identifying human-generated traffic as such, one can service it with improved reliabili ..."
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Cited by 36 (1 self)
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A large fraction of email spam, distributed denial-ofservice (DDoS) attacks, and click-fraud on web advertisements are caused by traffic sent from compromised machines that form botnets. This paper posits that by identifying human-generated traffic as such, one can service it with improved reliability or higher priority, mitigating the effects of botnet attacks. The key challenge is to identify human-generated traffic in the absence of strong unique identities. We develop NAB (“Not-A-Bot”), a system to approximately identify and certify human-generated activity. NAB uses a small trusted software component called an attester, which runs on the client machine with an untrusted OS and applications. The attester tags each request with an attestation if the request is made within a small amount of time of legitimate keyboard or mouse activity. The remote entity serving the request sends the request and attestation to a verifier, which checks the attestation and implements an application-specific policy for attested requests. Our implementation of the attester is within the Xen hypervisor. By analyzing traces of keyboard and mouse activity from 328 users at Intel, together with adversarial traces of spam, DDoS, and click-fraud activity, we estimate that NAB reduces the amount of spam that currently passes through a tuned spam filter by more than 92%, while not flagging any legitimate email as spam. NAB delivers similar benefits to legitimate requests under DDoS and click-fraud attacks. 1
Towards Trustworthy Participatory Sensing
"... Grassroots Participatory Sensing empowers people to collect and share sensor data using mobile devices across many applications, spanning intelligent transportation, air quality monitoring and social networking. In this paper, we argue that the very openness of such a system makes it vulnerable to a ..."
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Cited by 36 (5 self)
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Grassroots Participatory Sensing empowers people to collect and share sensor data using mobile devices across many applications, spanning intelligent transportation, air quality monitoring and social networking. In this paper, we argue that the very openness of such a system makes it vulnerable to abuse by malicious users who may poison the information, collude to fabricate information, or launch Sybils to distort that information. We propose and implement a novel trusted platform module (TPM), or angel based system that addresses the problem of providing sensor data integrity. The key idea is to provide a trusted platform within each sensor device to attest the integrity of sensor readings. We argue that this localizes integrity checking to the device, rather than relying on corroboration, making the system not only simpler, but also resistant to collusion and data poisoning. A “burnedin” private key in the TPM prevents users from launching Sybils. We also make the case for content protection and access control mechanisms that enable users to publish sensor data streams to selected groups of people and address it using broadcast encryption techniques. 1
Making argument systems for outsourced computation practical (sometimes
- In NDSS
, 2012
"... This paper describes the design, implementation, and evalu-ation of a system for performing verifiable outsourced com-putation. It has long been known that (1) this problem can be solved in theory using probabilistically checkable proofs (PCPs) coupled with modern cryptographic tools, and (2) these ..."
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Cited by 35 (6 self)
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This paper describes the design, implementation, and evalu-ation of a system for performing verifiable outsourced com-putation. It has long been known that (1) this problem can be solved in theory using probabilistically checkable proofs (PCPs) coupled with modern cryptographic tools, and (2) these solutions have wholly impractical performance, ac-cording to the conventional (and well-founded) wisdom. Our goal is to challenge (2), with a built system that im-plements an argument system based on PCPs. We describe a general-purpose system that builds on work of Ishai et al. (CCC ’07) and incorporates new theoretical work to im-prove performance by 20 orders of magnitude. The system is (arguably) practical in some cases, suggesting that, as a tool for building secure systems, PCPs are not a lost cause. 1
