2021 IEEE Symposium on Security and Privacy (SP)最新文献

{"title":"Android Custom Permissions Demystified: From Privilege Escalation to Design Shortcomings","authors":"Rui Li, Wenrui Diao, Zhou Li, Jianqi Du, Shanqing Guo","doi":"10.1109/SP40001.2021.00070","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00070","url":null,"abstract":"Permission is the fundamental security mechanism for protecting user data and privacy on Android. Given its importance, security researchers have studied the design and usage of permissions from various aspects. However, most of the previous research focused on the security issues of system permissions. Overlooked by many researchers, an app can use custom permissions to share its resources and capabilities with other apps. However, the security implications of using custom permissions have not been fully understood.In this paper, we systematically evaluate the design and implementation of Android custom permissions. Notably, we built an automatic fuzzing tool, called CuPerFuzzer, to detect custom permissions related vulnerabilities existing in the Android OS. CuPerFuzzer treats the operations of the permission mechanism as a black-box and executes massive targeted test cases to trigger privilege escalation. In the experiments, CuPerFuzzer discovered 2,384 effective cases with 30 critical paths successfully. Through investigating these vulnerable cases and analyzing the source code of Android OS, we further identified a series of severe design shortcomings lying in the Android permission framework, including dangling custom permission, inconsistent permission-group mapping, custom permission elevating, and inconsistent permission definition. Exploiting any of these shortcomings, a malicious app can obtain dangeroussystem permissions without user consent and further access unauthorized platform resources. On top of these observations, we propose some general design guidelines to secure custom permissions. Our findings have been acknowledged by the Android security team and rated as High severity.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"10 1","pages":"70-86"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82145712","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":"Bitcoin-Compatible Virtual Channels","authors":"Lukas Aumayr, O. Ersoy, Andreas Erwig, Sebastian Faust, Kristina Hostáková, Matteo Maffei, Pedro A. Moreno-Sánchez, S. Riahi","doi":"10.1109/SP40001.2021.00097","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00097","url":null,"abstract":"Current permissionless cryptocurrencies such as Bitcoin suffer from a limited transaction rate and slow confirmation time, which hinders further adoption. Payment channels are one of the most promising solutions to address these problems, as they allow the parties of the channel to perform arbitrarily many payments in a peer-to-peer fashion while uploading only two transactions on the blockchain. This concept has been generalized into payment channel networks where a path of payment channels is used to settle the payment between two users that might not share a direct channel between them. However, this approach requires the active involvement of each user in the path, making the system less reliable (they might be offline), more expensive (they charge fees per payment), and slower (intermediaries need to be actively involved in the payment). To mitigate this issue, recent work has introduced the concept of virtual channels (IEEE S&P’19), which involve intermediaries only in the initial creation of a bridge between payer and payee, who can later on independently perform arbitrarily many off-chain transactions. Unfortunately, existing constructions are only available for Ethereum, as they rely on its account model and Turing-complete scripting language. The realization of virtual channels in other blockchain technologies with limited scripting capabilities, like Bitcoin, was so far considered an open challenge.In this work, we present the first virtual channel protocols that are built on the UTXO-model and require a scripting language supporting only a digital signature scheme and a timelock functionality, being thus backward compatible with virtually every cryptocurrency, including Bitcoin. We formalize the security properties of virtual channels as an ideal functionality in the Universal Composability framework and prove that our protocol constitutes a secure realization thereof. We have prototyped and evaluated our protocol on the Bitcoin blockchain, demonstrating its efficiency: for n sequential payments, they require an off-chain exchange of 9+2n transactions or a total of 3524+695n bytes, with no on-chain footprint in the optimistic case. This is a substantial improvement compared to routing payments in a payment channel network, which requires 8n transactions with a total of 3026n bytes to be exchanged.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"5 1","pages":"901-918"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82281972","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":"SoK: Quantifying Cyber Risk","authors":"Daniel W. Woods, Rainer Böhme","doi":"10.1109/SP40001.2021.00053","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00053","url":null,"abstract":"This paper introduces a causal model inspired by structural equation modeling that explains cyber risk outcomes in terms of latent factors measured using reflexive indicators. First, we use the model to classify empirical cyber harm studies. We discover cyber harms are not exceptional in terms of typical or extreme losses. The increasing frequency of data breaches is contested and stock market reactions to cyber incidents are becoming less damaging over time. Focusing on harms alone breeds fatalism; the causal model is most useful in evaluating the effectiveness of security interventions. We show how simple statistical relationships lead to spurious results in which more security spending or applying updates are associated with greater rates of compromise. When accounting for threat and exposure, indicators of security are shown to be important factors in explaining the variance in rates of compromise, especially when the studies use multiple indicators of the security level.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"131 1","pages":"211-228"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79621157","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":"HackEd: A Pedagogical Analysis of Online Vulnerability Discovery Exercises","authors":"Daniel Votipka, Eric Zhang, Michelle L. Mazurek","doi":"10.1109/SP40001.2021.00092","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00092","url":null,"abstract":"Hacking exercises are a common tool for security education, but there is limited investigation of how they teach security concepts and whether they follow pedagogical best practices. This paper enumerates the pedagogical practices of 31 popular online hacking exercises. Specifically, we derive a set of pedagogical dimensions from the general learning sciences and educational literature, tailored to hacking exercises, and review whether and how each exercise implements each pedagogical dimension. In addition, we interview the organizers of 15 exercises to understand challenges and tradeoffs that may occur when choosing whether and how to implement each dimension.We found hacking exercises generally were tailored to students’ prior security experience and support learning by limiting extraneous load and establishing helpful online communities. Conversely, few exercises explicitly provide overarching conceptual structure or direct support for metacognition to help students transfer learned knowledge to new contexts. Immediate and tailored feedback and secure development practice were also uncommon. Additionally, we observed a tradeoff between providing realistic challenges and burdening students with extraneous cognitive load, with benefits and drawbacks at any point on this axis. Based on our results, we make suggestions for exercise improvement and future work to support organizers.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"23 1","pages":"1268-1285"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73436713","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":"On the Anonymity Guarantees of Anonymous Proof-of-Stake Protocols","authors":"Markulf Kohlweiss, Varun Madathil, Kartik Nayak, Alessandra Scafuro","doi":"10.1109/SP40001.2021.00107","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00107","url":null,"abstract":"In proof-of-stake (PoS) blockchains, stakeholders that extend the chain are selected according to the amount of stake they own. In S&P 2019 the \"Ouroboros Crypsinous\" system of Kerber et al. (and concurrently Ganesh et al. in EUROCRYPT 2019) presented a mechanism that hides the identity of the stakeholder when adding blocks, hence preserving anonymity of stakeholders both during payment and mining in the Ouroboros blockchain. They focus on anonymizing the messages of the blockchain protocol, but suggest that potential identity leaks from the network-layer can be removed as well by employing anonymous broadcast channels.In this work we show that this intuition is flawed. Even ideal anonymous broadcast channels do not suffice to protect the identity of the stakeholder who proposes a block.We make the following contributions. First, we show a formal network-attack against Ouroboros Crypsinous, where the adversary can leverage network delays to distinguish who is the stakeholder that added a block on the blockchain. Second, we abstract the above attack and show that whenever the adversary has control over the network delay – within the synchrony bound – loss of anonymity is inherent for any protocol that provides liveness guarantees. We do so, by first proving that it is impossible to devise a (deterministic) state-machine replication protocol that achieves basic liveness guarantees and better than (1−2f) anonymity at the same time (where f is the fraction of corrupted parties). We then connect this result to the PoS setting by presenting the tagging and reverse tagging attack that allows an adversary, across several executions of the PoS protocol, to learn the stake of a target node, by simply delaying messages for the target. We demonstrate that our assumption on the delaying power of the adversary is realistic by describing how our attack could be mounted over the Zcash blockchain network (even when Tor is used). We conclude by suggesting approaches that can mitigate such attacks.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"5 1","pages":"1818-1833"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84665240","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":"Diane: Identifying Fuzzing Triggers in Apps to Generate Under-constrained Inputs for IoT Devices","authors":"Nilo Redini, Andrea Continella, Dipanjan Das, Giulio De Pasquale, Noah Spahn, Aravind Machiry, Antonio Bianchi, C. Kruegel, G. Vigna","doi":"10.1109/SP40001.2021.00066","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00066","url":null,"abstract":"Internet of Things (IoT) devices have rooted themselves in the everyday life of billions of people. Thus, researchers have applied automated bug finding techniques to improve their overall security. However, due to the difficulties in extracting and emulating custom firmware, black-box fuzzing is often the only viable analysis option. Unfortunately, this solution mostly produces invalid inputs, which are quickly discarded by the targeted IoT device and do not penetrate its code. Another proposed approach is to leverage the companion app (i.e., the mobile app typically used to control an IoT device) to generate well-structured fuzzing inputs. Unfortunately, the existing solutions produce fuzzing inputs that are constrained by app-side validation code, thus significantly limiting the range of discovered vulnerabilities.In this paper, we propose a novel approach that overcomes these limitations. Our key observation is that there exist functions inside the companion app that can be used to generate optimal (i.e., valid yet under-constrained) fuzzing inputs. Such functions, which we call fuzzing triggers, are executed before any data-transforming functions (e.g., network serialization), but after the input validation code. Consequently, they generate inputs that are not constrained by app-side sanitization code, and, at the same time, are not discarded by the analyzed IoT device due to their invalid format. We design and develop Diane, a tool that combines static and dynamic analysis to find fuzzing triggers in Android companion apps, and then uses them to fuzz IoT devices automatically. We use Diane to analyze 11 popular IoT devices, and identify 11 bugs, 9 of which are zero days. Our results also show that without using fuzzing triggers, it is not possible to generate bug-triggering inputs for many devices.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"110 1","pages":"484-500"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86234931","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":"Happer: Unpacking Android Apps via a Hardware-Assisted Approach","authors":"Lei Xue, Hao Zhou, Xiapu Luo, Yajin Zhou, Yang Shi, G. Gu, Fengwei Zhang, M. Au","doi":"10.1109/SP40001.2021.00105","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00105","url":null,"abstract":"Malware authors are abusing packers (or runtime-based obfuscators) to protect malicious apps from being analyzed. Although many unpacking tools have been proposed, they can be easily impeded by the anti-analysis methods adopted by the packers, and they fail to effectively collect the hidden Dex data due to the evolving protection strategies of packers. Consequently, many packing behaviors are unknown to analysts and packed malware can circumvent the inspection. To fill the gap, in this paper, we propose a novel hardware-assisted approach that first monitors the packing behaviors and then selects the proper approach to unpack the packed apps. Moreover, we develop a prototype named Happerwith a domain-specific language named behavior description language (BDL) for the ease of extending Happerafter tackling several technical challenges. We conduct extensive experiments with 12 commercial Android packers and more than 24k Android apps to evaluate Happer. The results show that Happerobserved 27 packing behaviors, 17 of which have not been elaborated by previous studies. Based on the observed packing behaviors, Happeradopted proper approaches to collect all the hidden Dex data and assembled them to valid Dex files.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"25 22 1","pages":"1641-1658"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89803095","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":"Method Confusion Attack on Bluetooth Pairing","authors":"Maximilian von Tschirschnitz, Ludwig Peuckert, Fabian Franzen, Jens Grossklags","doi":"10.1109/SP40001.2021.00013","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00013","url":null,"abstract":"Bluetooth provides encryption, authentication, and integrity protection of its connections. These protection mechanisms require that Bluetooth devices initially establish trust on first use through a process called pairing. Throughout this process, multiple alternative pairing methods are supported.In this paper, we describe a design flaw in the pairing mechanism of Bluetooth. This flaw permits two devices to perform pairing using differing methods. While successfully interacting with each other, the devices are not aware of the Method Confusion. We explain how an attacker can cause and abuse this Method Confusion to mount a Method Confusion Attack. In contrast to other attacks targeting the pairing method, our attack applies even in Bluetooth’s highest security mode and cannot be mitigated in the protocol. Through the Method Confusion Attack, an adversary can infiltrate the secured connection between the victims and intercept all traffic.Our attack is successful in practically relevant scenarios. We implemented it as an end-to-end Proof of Concept for Bluetooth Low Energy and tested it with off-the-shelf smartphones, a smartwatch and a banking device. Furthermore, we performed a user study where none of the 40 participants noticed the ongoing attack, and 37 (92.5%) of the users completed the pairing process. Finally, we propose changes to the Bluetooth specification that immunize it against our attack.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"20 1","pages":"1332-1347"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90936582","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":"Poltergeist: Acoustic Adversarial Machine Learning against Cameras and Computer Vision","authors":"Xiaoyu Ji, Yushi Cheng, Yuepeng Zhang, Kai Wang, Chen Yan, Wenyuan Xu, Kevin Fu","doi":"10.1109/SP40001.2021.00091","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00091","url":null,"abstract":"Autonomous vehicles increasingly exploit computer-vision-based object detection systems to perceive environments and make critical driving decisions. To increase the quality of images, image stabilizers with inertial sensors are added to alleviate image blurring caused by camera jitters. However, such a trend opens a new attack surface. This paper identifies a system-level vulnerability resulting from the combination of the emerging image stabilizer hardware susceptible to acoustic manipulation and the object detection algorithms subject to adversarial examples. By emitting deliberately designed acoustic signals, an adversary can control the output of an inertial sensor, which triggers unnecessary motion compensation and results in a blurred image, even if the camera is stable. The blurred images can then induce object misclassification affecting safety-critical decision making. We model the feasibility of such acoustic manipulation and design an attack framework that can accomplish three types of attacks, i.e., hiding, creating, and altering objects. Evaluation results demonstrate the effectiveness of our attacks against four academic object detectors (YOLO V3/V4/V5 and Fast R-CNN), and one commercial detector (Apollo). We further introduce the concept of AMpLe attacks, a new class of system-level security vulnerabilities resulting from a combination of adversarial machine learning and physics-based injection of information-carrying signals into hardware.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"27 1","pages":"160-175"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81057294","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":"Systematic Analysis of Randomization-based Protected Cache Architectures","authors":"Antoon Purnal, Lukas Giner, D. Gruss, I. Verbauwhede","doi":"10.1109/SP40001.2021.00011","DOIUrl":"https://doi.org/10.1109/SP40001.2021.00011","url":null,"abstract":"Recent secure cache designs aim to mitigate side-channel attacks by randomizing the mapping from memory addresses to cache sets. As vendors investigate deployment of these caches, it is crucial to understand their actual security.In this paper, we consolidate existing randomization-based secure caches into a generic cache model. We then comprehensively analyze the security of existing designs, including CEASER-S and SCATTERCACHE, by mapping them to instances of this model. We tailor cache attacks for randomized caches using a novel PRIME+PRUNE+PROBE technique, and optimize it using burst accesses, bootstrapping, and multi-step profiling. PRIME+ PRUNE+PROBE constructs probabilistic but reliable eviction sets, enabling attacks previously assumed to be computationally infeasible. We also simulate an end-to-end attack, leaking secrets from a vulnerable AES implementation. Finally, a case study of CEASER-S reveals that cryptographic weaknesses in the randomization algorithm can lead to a complete security subversion.Our systematic analysis yields more realistic and comparable security levels for randomized caches. As we quantify how design parameters influence the security level, our work leads to important conclusions for future work on secure cache designs.","PeriodicalId":6786,"journal":{"name":"2021 IEEE Symposium on Security and Privacy (SP)","volume":"19 1","pages":"987-1002"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78595005","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}