2016 IEEE European Symposium on Security and Privacy (EuroS&P)最新文献

{"title":"Foundations of Hardware-Based Attested Computation and Application to SGX","authors":"M. Barbosa, Bernardo Portela, Guillaume Scerri, B. Warinschi","doi":"10.1109/EuroSP.2016.28","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.28","url":null,"abstract":"Exciting new capabilities of modern trusted hardware technologies allow for the execution of arbitrary code within environments completely isolated from the rest of the system and provide cryptographic mechanisms for securely reporting on these executions to remote parties. Rigorously proving security of protocols that rely on this type of hardware faces two obstacles. The first is to develop models appropriate for the induced trust assumptions (e.g., what is the correct notion of a party when the peer one wishes to communicate with is a specific instance of an an outsourced program). The second is to develop scalable analysis methods, as the inherent stateful nature of the platforms precludes the application of existing modular analysis techniques that require high degrees of independence between the components. We give the first steps in this direction by studying three cryptographic tools which have been commonly associated with this new generation of trusted hardware solutions. Specifically, we provide formal security definitions, generic constructions and security analysis for attested computation, key-exchange for attestation and secure outsourced computation. Our approach is incremental: each of the concepts relies on the previous ones according to an approach that is quasi-modular. For example we show how to build a secure outsourced computation scheme from an arbitrary attestation protocol combined together with a key-exchange and an encryption scheme.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115294940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CacheKit: Evading Memory Introspection Using Cache Incoherence","authors":"Ning Zhang, He Sun, Kun Sun, W. Lou, Yiwei Thomas Hou","doi":"10.1109/EuroSP.2016.34","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.34","url":null,"abstract":"With the growing importance of networked embedded devices in the upcoming Internet of Things, new attacks targeting embedded OSes are emerging. ARM processors, which power over 60% of embedded devices, introduce a hardware security extension called TrustZone to protect secure applications in an isolated secure world that cannot be manipulated by a compromised OS in the normal world. Leveraging TrustZone technology, a number of memory integrity checking schemes have been proposed in the secure world to introspect malicious memory modification of the normal world. In this paper, we first discover and verify an ARM TrustZone cache incoherence behavior, which results in the cache contents of the two worlds, secure and non-secure, potentially being different even when they are mapped to the same physical address. Furthermore, code in one TrustZone world cannot access the cache content in the other world. Based on this observation, we develop a new rootkit called CacheKit that hides in the cache of the normal world and is able to evade memory introspection from the secure world. We implement a CacheKit prototype on Cortex-A8 processors after solving a number of challenges. First, we employ the Cache-as-RAM technique to ensure that the malicious code is only loaded into the CPU cache and not RAM. Thus, the secure world cannot detect the existence of the malicious code by examining the RAM. Second, we use the ARM processor's hardware support on cache settings to keep the malicious code persistent in the cache. Third, to evade introspection that flushes cache content back into RAM, we utilize physical addresses from the I/O address range that is not backed by any real I/O devices or RAM. The experimental results show that CacheKit can successfully evade memory introspection from the secure world and has small performance impacts on the rich OS. We discuss potential countermeasures to detect this type of rootkit attack.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122935719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frigate: A Validated, Extensible, and Efficient Compiler and Interpreter for Secure Computation","authors":"Benjamin Mood, Debayan Gupta, Henry Carter, Kevin R. B. Butler, Patrick Traynor","doi":"10.1109/EuroSP.2016.20","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.20","url":null,"abstract":"Recent developments in secure computation have led to significant improvementsin efficiency and functionality. These efforts created compilers that form thebackbone of practical secure computation research. Unfortunately, many of theartifacts that are being used to demonstrate new research for secure computationare incomplete, incorrect, or unstable, leading to demonstrably erroneousresults and inefficiencies - extending even to the most recently developedcompiler systems. This is a problem because it hampers research and underminesfeasibility tests when other researchers attempt to use these tools. We addressthese problems and present Frigate, a principled compiler and fast circuitinterpreter for secure computation. To ensure correctness we apply bestpractices for compiler design and development, including the use of standarddata structures, helpful negative results, and structured validation testing. Our systematic validation tests include checks on the internal compiler state, combinations of operators, and edge cases based on widely used techniques anderrors we have observed in other work. This produces a compiler that buildscorrect circuits, is efficient and extensible. Frigate creates circuits withgate counts comparable to previous work, but does so with compile time speedupsas high as 447x compared with the best results from previous work in circuit compilers. By creating avalidated tool, our compiler will allow future secure computationimplementations to be developed quickly and correctly.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126877760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine-Grained Control-Flow Integrity for Kernel Software","authors":"Xinyang Ge, Nirupama Talele, Mathias Payer, T. Jaeger","doi":"10.1109/EuroSP.2016.24","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.24","url":null,"abstract":"Modern systems assume that privileged software always behaves as expected, however, such assumptions may not hold given the prevalence of kernel vulnerabilities. One idea is to employ defenses to restrict how adversaries may exploit such vulnerabilities, such as Control-Flow Integrity (CFI), which restricts execution to a Control-Flow Graph (CFG). However, proposed applications of CFI enforcement to kernel software are too coarse-grained to restrict the adversary effectively and either fail to enforce CFI comprehensively or are very expensive. We present a mostly-automated approach for retrofitting kernel software that leverages features of such software to enable comprehensive, efficient, fine-grained CFI enforcement. We achieve this goal by leveraging two insights. We first leverage the conservative function pointer usage patterns found in the kernel source code to develop a method to compute fine-grained CFGs for kernel software. Second, we identify two opportunities for removing CFI instrumentation relative to prior optimization techniques: reusing existing kernel instrumentation and creating direct transfers, where possible. Using these insights, we show how to choose optimized defenses for kernels to handle system events, enabling comprehensive and efficient CFI enforcement. We evaluate the effectiveness of the proposed fine-grained CFI instrumentation by applying the retrofitting approach comprehensively to FreeBSD, the MINIX microkernel system, and MINIX's user-space servers, and applying this approach partly to the BitVisor hypervisor. We show that our approach eliminates over 70% of the indirect targets relative to the best current, fine-grained CFI techniques, while our optimizations reduce the instrumentation necessary to enforce coarse-grained CFI. The performance improvement due to our optimizations ranges from 51%/25% for MINIX to 12%/17% for FreeBSD for the average/maximum microbenchmark overhead. The evaluation shows that fine-grained CFI instrumentation can be computed for kernel software in practice and can be enforced more efficiently than coarse-grained CFI instrumentation.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131055925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How Secure is TextSecure?","authors":"Tilman Frosch, Christian Mainka, Christoph Bader, Florian Bergsma, Jörg Schwenk, Thorsten Holz","doi":"10.1109/EUROSP.2016.41","DOIUrl":"https://doi.org/10.1109/EUROSP.2016.41","url":null,"abstract":"Instant Messaging has gained popularity by users for both private and business communication as low-cost short message replacement on mobile devices. However, before releases about mass surveillance performed by intelligence services such as NSA and GCHQ and Facebook's acquisition of WhatsApp, most mobile messaging apps did not protect confidentiality or integrity of the messages. A messaging app that claims to provide secure instant messaging and has attracted a lot of attention is TextSecure. Besides numerous direct installations, its protocol is part of Android's most popular aftermarket firmware Cyanogen-Mod. TextSecure's successor Signal continues to use the underlying protocol for text messaging. In this paper, we present the first complete description of TextSecure's complex cryptographic protocol, provide a security analysis of its three main components (key exchange, key derivation and authenticated encryption), and discuss the main security claims of TextSecure. Furthermore, we formally prove that - if key registration is assumed to be secure - TextSecure's push messaging can indeed achieve most of the claimed security goals.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129027869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NavigaTor: Finding Faster Paths to Anonymity","authors":"Robert Annessi, Martin Schmiedecker","doi":"10.1109/EuroSP.2016.26","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.26","url":null,"abstract":"The Tor network is currently by far the most popular system for providing anonymity on the Internet. Even though both latency and throughput have been significantly improved in recent years, Tor users still experience variable delays on connecting to servers. Such delays have been shown to be especially harmful for browsing the web and prevent altogether the use of protocols where a certain quality of service is indispensable. In this paper we propose and evaluate methods to measure and improve performance in the Tor network. To estimate the quality of circuits for future traffic, we use active Round-Trip-Time (RTT) measurements and a-priori information of the distribution of RTT values. In this way, slow circuits can be discarded before having negative impact on user experience. Using NavigaTor, our high performance measurement software which includes a custom Tor path generator, we are the first to conduct large-scale performance measurements on the live Tor network, building millions of circuits within days, without stressing the anonymity network. As part of our study, we conduct several experiments from PlanetLab on the live Tor network to analyze the trade-off between the quality of protection and the quality of service. We compare our Circuit-RTT method to the current state-of-the-art method Circuit Build Time (CBT) and the more recently proposed congestion-aware scheme, finding that the congestion-aware scheme in its original design achieves only minor improvements on the current Tor network and that Circuit-RTT improves latency and throughput more effectively than CBT.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"214 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122378232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The OPTLS Protocol and TLS 1.3","authors":"H. Krawczyk, H. Wee","doi":"10.1109/EuroSP.2016.18","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.18","url":null,"abstract":"We present the OPTLS key-exchange protocol, its design, rationale and cryptographic analysis. OPTLS design has been motivated by the ongoing work in the TLS working group of the IETF for specifying TLS 1.3, the next-generation TLS protocol. The latter effort is intended to revamp the security of TLS that has been shown inadequate in many instances as well as to add new security and functional features. The main additions that influence the cryptographic design of TLS 1.3 (hence also of OPTLS) are a new \"0-RTT requirement\" (0-RTT stands for \"zero round trip time\") to allow clients that have previously retrieved or cached the public key of the server to send protected data already in the first flow of the protocol, making perfect forward secrecy (PFS) a mandatory requirement, and moving to elliptic curves as the main cryptographic basis for the protocol (for performance and security reasons). Accommodating these requirements calls for moving away from the RSA-centric design of TLS in favor of a protocol based on Diffie-Hellman techniques. OPTLS offers a simple design framework that supports all the above requirements from the protocol with a uniform and modular logic that helps in the specification, analysis, performance optimization, and future maintenance of the protocol. The current (draft) specification of TLS 1.3 builds upon the OPTLS framework as a basis for the cryptographic core of the handshake protocol adapting the different modes of OPTLS to the TLS 1.3 context.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"49 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125149920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reasoning about Object Capabilities with Logical Relations and Effect Parametricity","authors":"Dominique Devriese, L. Birkedal, F. Piessens","doi":"10.1109/EuroSP.2016.22","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.22","url":null,"abstract":"Object capabilities are a technique for fine-grained privilege separation in programming languages and systems, with important applications in security. However, current formal characterisations do not fully capture capability-safety of a programming language and are not sufficient for verifying typical applications. Using state-of-the-art techniques from programming languages research, we define a logical relation for a core calculus of JavaScript that better characterises capability-safety. The relation is powerful enough to reason about typical capability patterns and supports evolvable invariants on shared data structures, capabilities with restricted authority over them and isolated components with restricted communication channels. We use a novel notion of effect parametricity for deriving properties about effects. Our results imply memory access bounds that have previously been used to characterise capability-safety.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129958382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extended Functionality Attacks on IoT Devices: The Case of Smart Lights","authors":"Eyal Ronen, A. Shamir","doi":"10.1109/EuroSP.2016.13","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.13","url":null,"abstract":"In this paper we consider the security aspects of Internet of Things (IoT) devices, which bridge the physical and virtual worlds. We propose a new taxonomy of attacks, which classifies them into four broad categories. The most interesting category (which we call functionality extension attacks) uses the designed functionality of the IoT device to achieve a totally different effect. To demonstrate this type of attack, we consider the case of smart lights (whose original functionality is just to control the color and intensity of the lights in a particular room) and show how to use them to achieve unrelated effects. In the first attack, we use smart lights as a covert LIFI communication system to exfiltrate data from a highly secure (or even fully airgapped) office building. We implemented the attack and were able to read the leaked data from a distance of over 100 meters using only cheap and readily available equipment. In another attack, we showed that an attacker can strobe the lights at a frequency which may trigger seizures in people suffering from photosensitive epilepsy (in the same way that rapidly flashing video games can cause such seizures). In our experiments, we have tested both high-end and lower-end smart light systems, ranging from an expensive Philips HUE system to a cheap system manufactured by LimitlessLED. In addition, we consider other weaknesses of the systems we tested, and propose feasible remedies for the problems we found.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127015373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"I am Robot: (Deep) Learning to Break Semantic Image CAPTCHAs","authors":"Suphannee Sivakorn, Iasonas Polakis, A. Keromytis","doi":"10.1109/EuroSP.2016.37","DOIUrl":"https://doi.org/10.1109/EuroSP.2016.37","url":null,"abstract":"Since their inception, captchas have been widely used for preventing fraudsters from performing illicit actions. Nevertheless, economic incentives have resulted in an arms race, where fraudsters develop automated solvers and, in turn, captcha services tweak their design to break the solvers. Recent work, however, presented a generic attack that can be applied to any text-based captcha scheme. Fittingly, Google recently unveiled the latest version of reCaptcha. The goal of their new system is twofold, to minimize the effort for legitimate users, while requiring tasks that are more challenging to computers than text recognition. ReCaptcha is driven by an \"advanced risk analysis system\" that evaluates requests and selects the difficulty of the captcha that will be returned. Users may be required to click in a checkbox, or solve a challenge by identifying images with similar content. In this paper, we conduct a comprehensive study of reCaptcha, and explore how the risk analysis process is influenced by each aspect of the request. Through extensive experimentation, we identify flaws that allow adversaries to effortlessly influence the risk analysis, bypass restrictions, and deploy large-scale attacks. Subsequently, we design a novel low-cost attack that leverages deep learning technologies for the semantic annotation of images. Our system is extremely effective, automatically solving 70.78% of the image reCaptcha challenges, while requiring only 19 seconds per challenge. We also apply our attack to the Facebook image captcha and achieve an accuracy of 83.5%. Based on our experimental findings, we propose a series of safeguards and modifications for impacting the scalability and accuracy of our attacks. Overall, while our study focuses on reCaptcha, our findings have wide implications, as the semantic information conveyed via images is increasingly within the realm of automated reasoning, the future of captchas relies on the exploration of novel directions.","PeriodicalId":415361,"journal":{"name":"2016 IEEE European Symposium on Security and Privacy (EuroS&P)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116403895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}