可信执行环境软件侧信道攻击研究综述

为保护计算设备中安全敏感程序运行环境的安全,研究人员提出了可信执行环境(TEE)技术,通过对硬件和软件进行隔离为安全敏感程序提供一个与通用计算环境隔离的安全运行环境.侧信道攻击从传统的需要昂贵设备发展到现在仅基于微体系结构状态就能通过软件方式获取机密信息的访问模式,从而进一步推测出机密信息.TEE架构仅提供隔离机制,无法抵抗这类新出现的软件侧信道攻击.深入调研了ARM TrustZone、Intel SGX和AMD SEV这3种TEE架构的软件侧信道攻击及相应防御措施,并探讨其攻击和防御机制的发展趋势.首先,介绍了ARM TrustZone、Intel SGX和AMD SEV的基本原理,并详细阐述了软件侧信道攻击的定义以及缓存侧信道攻击的分类、方法和步骤;之后从处理器指令执行的角度,提出一种TEE攻击面分类方法,利用该方法对TEE软件侧信道攻击进行分类,并阐述了软件侧信道攻击与其他攻击相结合的组合攻击;然后详细讨论TEE软件侧信道攻击的威胁模型;最后全面总结业界对TEE软件侧信道攻击的防御措施,并从攻击和防御两方面探讨TEE软件侧信道攻击未来的研究趋势.     

A survey of Intel SGX and its applications

This paper presents a comprehensive survey on the development of Intel SGX (software guard extensions) processors and its applications. With the advent of SGX in 2013 and its subsequent development, the corresponding research works are also increasing rapidly. In order to get a more comprehensive literature review related to SGX, we have made a systematic analysis of the related papers in this area. We first search through five large-scale paper retrieval libraries by keywords (i.e., ACM Digital Library, IEEE/IET Electronic Library, SpringerLink, Web of Science, and Elsevier Science Direct). We read and analyze a total of 128 SGX-related papers. The first round of extensive study is conducted to classify them. The second round of intensive study is carried out to complete a comprehensive analysis of the paper from various aspects. We start with the working environment of SGX and make a conclusive summary of trusted execution environment (TEE).We then focus on the applications of SGX. We also review and study multifarious attack methods to SGX framework and some recent security improvementsmade on SGX. Finally, we summarize the advantages and disadvantages of SGX with some future research opportunities. We hope this review could help the existing and future research works on SGX and its application for both developers and users.     

Security-enhanced live migration based on SGX for virtual machine

The virtual machine may face the problem of information leakage in live migration.Therefore,a dynamic memory protection technique SGX was introduced and a security enhancement live migration method based on KVM environment was proposed.Firstly,on both sides of migration,a hardware-isolated secure execution environment centered SGX was built.It guaranteed the security of operations like encryption and integrity measurement and also ensured the security of private data.An encrypted channel to transfer migration data based on the remote attestation between the secure execution environments of both migration sides was constructed.And the mutual authentication of both sides’ platform integrity was realized.Finally,the security enhancement effect and did the experiment was analyzed.The results shows that the introduction of SGX won’t cause much negative effect to the migration performance.     

A Distributed Privacy Preservation Approach for Big Data in Public Health Emergencies Using Smart Contract and SGX

Security and privacy issues have become a rapidly growing problem with the fast development of big data in public health. However, big data faces many ongoing serious challenges in the process of collection, storage, and use. Among them, data security and privacy problems have attracted extensive interest. In an effort to overcome this challenge, this article aims to present a distributed privacy preservation approach based on smart contracts and Intel Software Guard Extensions (SGX). First of all, we define SGX as a trusted edge computing node, design data access module, data protection module, and data integrity check module, to achieve hardware-enhanced data privacy protection. Then, we design a smart contract framework to realize distributed data access control management in a big data environment. The crucial role of the smart contract was revealed by designing multiple access control contracts, register contracts, and history contracts. Access control contracts provide access control methods for different users and enable static access verification and dynamic access verification by checking the user’s properties and history behavior. Register contract contains user property information, edge computing node information, the access control and history smart contract information, and provides functions such as registration, update, and deletion. History contract records the historical behavior information of malicious users, receives the report information of malicious requestors from the access control contract, implements a misbehavior check method to determines whether the requestor has misbehavior, and returns the corresponding result. Finally, we design decentralized system architecture, prove the security properties, and analysis to verify the feasibility of the system. Results demonstrate that our method can effectively improve the timeliness of data, reduce network latency, and ensure the security, reliability, and traceability of data.     

SeDID: An SGX-enabled decentralized intrusion detection framework for network trust evaluation

In order to evaluate network trust, different intrusion detection methods have been proposed. However, it is difficult for a single detection node to collect massive data and perform detection and evaluation in a large-scale network. In addition, disclosure of security-related data and detection pattern might weaken data provision incentives due to privacy concern, which could result in deliberately forging data to evade detection. Current literature still lacks a general framework to conduct decentralized intrusion detection towards network trust evaluation with privacy preservation. In this paper, we propose SeDID, a Software Guard Extension (SGX)-enabled decentralized intrusion detection framework for network trust evaluation based on blockchain. We design a novel consensus mechanism to avoid forking and guarantee high efficiency and real decentralization, where block creation is uniquely consented by miners and block creation difficulty is determined by the number of blocks previously created by a relative miner within a time window. The smaller the number, the easier the miner creates a new block. SeDID also offers incentives according to node contributions for motivating security-related data collection, intrusion detection and network trust evaluation. Additional employment of Intel SGX makes SeDID preserve both data and pattern privacy. We analyze SeDID’s efficacy in terms of incentive, privacy preservation and security. Its performance is further evaluated through simulations. In specific settings, its block creation time, task completion time and throughput are 19.61s, 44.55s and 224.47 transactions/s, respectively. Compared with state-of-the-art systems, SeDID offers better performance, which implies its potential to be applied in practice.     

Selective chalcopyrite flotation from pyrite with glycerine-xanthate as depressant

Micro-flotation tests, adsorption, electrokinetic and FTIR measurements were carried out in order to investigate the selective depression mechanism of sodium glycerine-xanthate (SGX) on pyrite in chalcopyrite flotation. The flotation results showed a large difference in chalcopyrite (>85%) and pyrite (<30%) recovery as stirred pulp-mixing with SGX before the addition of collector sodium butyl xanthate (SBX), at the range of pH 7–10. A much stronger adsorption of SGX on pyrite than chalcopyrite was dramatically revealed by zeta potential measurements, which can explain the better floatability of chalcopyrite than pyrite. The adsorption of SBX onto pyrite was depressed intensely while that onto chalcopyrite was affected slightly when SGX was used as depressant, because of more stronger adsorption between SGX and SBX occurring onto the pyrite surfaces. The absorbed amount of SGX on chalcopyrite increases slightly, over the pH range from 3 to 12, while that on pyrite increases rapidly with the increased SGX concentration, which is consistent with the flotation results. FTIR reflection spectroscopic measurements further demonstrated the depression effect of pre-absorbed SGX on SBX adsorption, which is attributed to its hydrophilic hydroxyl groups.     

应用内存超售在虚拟化环境中优化SGX的性能

随着安全性在云计算中越来越受到关注,英特尔自2015年起提出了SGX.它提供enclave,并保护enclave中的应用程序免受不信任的软件(包括客户操作系统和虚拟机监视器)和硬件(英特尔CPU包除外)的攻击.然而,SGX只能支持256MB的enclave内存EPC.因此,在不同的虚拟机之间高效分配宝贵的EPC资源对整...     

SGX技术的分析和研究

安全性是云计算中一项极为重要的需求,然而如何保护云计算中关键应用程序和数据的安全、防止云平台管理员泄露用户隐私,仍然是目前没有解决的难题.2013年,Intel公司提出了新的处理器安全技术SGX,能够在计算平台上提供一个可信的隔离空间,保障用户关键代码和数据的机密性和完整性.作为系统安全领域的重大研究进展,SGX对系统安全,尤其是云计算安全保护方面具有非常重要的意义.该文介绍了SGX的原理和特性,分析了SGX的关键技术以及针对SGX的侧信道攻击及防御方法.同时,总结和归纳了该技术的研究成果,分析了SGX技术与其他可信计算技术的异同,并指出了SGX技术的未来研究挑战和应用需求.     

EPMDroid: Efficient and privacy-preserving malware detection based on SGX through data fusion

Android has stood at a predominant position in mobile operating systems for many years. However, its popularity and openness make it a desirable target of malicious attackers. There is an increasing need for mobile malware detection. Existing analysis methods fall into two categories, i.e., static analysis and dynamic analysis. The dynamic analysis is more effective and timely than the static one, but it incurs a high computational overhead, thus cannot be deployed in resource-constrained mobile devices. Existing studies solve this issue by outsourcing malware detection to the cloud. However, the privacy of mobile app runtime data uploaded to the cloud is not well preserved during both detection model training and malware detection. Numerous efforts have been made to preserve privacy with cryptography, which suffers from high computational overhead and low flexibility. To address these issues, in this paper, we propose an Intel SGX-empowered mobile malware detection scheme called EPMDroid. We also design a probabilistic data structure based on cuckoo filters, named CuckooTable, to effectively fuse features for detection and achieve high space efficiency. We conduct both theoretical analysis and real-world data based tests on EPMDroid performance. Experimental results show that EPMDroid can speed up malware detection by up to 43.8 times and save memory space by up to 3.7 times with the same accuracy, as compared to a baseline method.     

基于Intel SGX的Ansible安全增强

Ansible是当今最主流的云平台自动化运维工具之一,通常拥有大量集群的管理员账号信息来批量执行运维任务,这些账号信息一般明文存储在配置文件中.但在云计算环境中这种机制具有较大的安全隐患,因为Ansible的配置信息的机密性和完整性依赖云服务厂商提供的基础软件的安全性.因此,加强Ansible配置信息管理机制的安全性至关重要.本文基于Intel近年推出的安全机制SGX（Software Guard eXtensions）开发了Ansible的配置管理模块,它可以独立地在可信的执行环境（Trusted Execution Environment,TEE）内管理Ansible的配置信息,从而保证了Ansible配置信息不被外界读取和修改,同时其安全性不再依赖于底层基础软件.实验评估显示,本文方案更加安全可靠,性能的额外开销也在接受范围之内,而且可以进一步扩展成通用的配置管理组件集成到OpenStack等云平台中.