Adaptive Microarchitectural Optimizations to Improve Performance and Security of Multi-Core Architectures

With the current technological barriers, microarchitectural optimizations are increasingly important to ensure performance scalability of computing systems. The shift to multi-core architectures increases the demands on the memory system, and amplifies the role of microarchitectural optimizations in performance improvement. In a multi-core system, microarchitectural resources are usually shared, such as the cache, to maximize utilization but sharing can also lead to contention and lower performance. This can be mitigated through partitioning of shared caches.However, microarchitectural optimizations which were assumed to be fundamentally secure for a long time, can be used in side-channel attacks to exploit secrets, as cryptographic keys. Timing-based side-channels exploit predictable timing variations due to the interaction with microarchitectural optimizations during program execution. Going forward, there is a strong need to be able to leverage microarchitectural optimizations for performance without compromising security. This thesis contributes with three adaptive microarchitectural resource management optimizations to improve security and/or\ua0performance\ua0of multi-core architectures\ua0and a systematization-of-knowledge of timing-based side-channel attacks.\ua0We observe that to achieve high-performance cache partitioning in a multi-core system\ua0three requirements need to be met: i) fine-granularity of partitions, ii) locality-aware placement and iii) frequent changes. These requirements lead to\ua0high overheads for current centralized partitioning solutions, especially as the number of cores in the\ua0system increases. To address this problem, we present an adaptive and scalable cache partitioning solution (DELTA) using a distributed and asynchronous allocation algorithm. The\ua0allocations occur through core-to-core challenges, where applications with larger performance benefit will gain cache capacity. The\ua0solution is implementable in hardware, due to low computational complexity, and can scale to large core counts.According to our analysis, better performance can be achieved by coordination of multiple optimizations for different resources, e.g., off-chip bandwidth and cache, but is challenging due to the increased number of possible allocations which need to be evaluated.\ua0Based on these observations, we present a solution (CBP) for coordinated management of the optimizations: cache partitioning, bandwidth partitioning and prefetching.\ua0Efficient allocations, considering the inter-resource interactions and trade-offs, are achieved using local resource managers to limit the solution space.The continuously growing number of\ua0side-channel attacks leveraging\ua0microarchitectural optimizations prompts us to review attacks and defenses to understand the vulnerabilities of different microarchitectural optimizations. We identify the four root causes of timing-based side-channel attacks: determinism, sharing, access violation\ua0and information flow.\ua0Our key insight is that eliminating any of the exploited root causes, in any of the attack steps, is enough to provide protection.\ua0Based on our framework, we present a systematization of the attacks and defenses on a wide range of microarchitectural optimizations, which highlights their key similarities.\ua0Shared caches are an attractive attack surface for side-channel attacks, while defenses need to be efficient since the cache is crucial for performance.\ua0To address this issue, we present an adaptive and scalable cache partitioning solution (SCALE) for protection against cache side-channel attacks. The solution leverages randomness,\ua0and provides quantifiable and information theoretic security guarantees using differential privacy. The solution closes the performance gap to a state-of-the-art non-secure allocation policy for a mix of secure and non-secure applications

Discrete Event Simulations

Considered by many authors as a technique for modelling stochastic, dynamic and discretely evolving systems, this technique has gained widespread acceptance among the practitioners who want to represent and improve complex systems. Since DES is a technique applied in incredibly different areas, this book reflects many different points of view about DES, thus, all authors describe how it is understood and applied within their context of work, providing an extensive understanding of what DES is. It can be said that the name of the book itself reflects the plurality that these points of view represent. The book embraces a number of topics covering theory, methods and applications to a wide range of sectors and problem areas that have been categorised into five groups. As well as the previously explained variety of points of view concerning DES, there is one additional thing to remark about this book: its richness when talking about actual data or actual data based analysis. When most academic areas are lacking application cases, roughly the half part of the chapters included in this book deal with actual problems or at least are based on actual data. Thus, the editor firmly believes that this book will be interesting for both beginners and practitioners in the area of DES

Cross-VM network attacks & their countermeasures within cloud computing environments

Cloud computing is a contemporary model in which the computing resources are dynamically scaled-up and scaled-down to customers, hosted within large-scale multi-tenant systems. These resources are delivered as improved, cost-effective and available upon request to customers. As one of the main trends of IT industry in modern ages, cloud computing has extended momentum and started to transform the mode enterprises build and offer IT solutions. The primary motivation in using cloud computing model is cost-effectiveness. These motivations can compel Information and Communication Technologies (ICT) organizations to shift their sensitive data and critical infrastructure on cloud environments. Because of the complex nature of underlying cloud infrastructure, the cloud environments are facing a large number of challenges of misconfigurations, cyber-attacks, root-kits, malware instances etc which manifest themselves as a serious threat to cloud environments. These threats noticeably decline the general trustworthiness, reliability and accessibility of the cloud. Security is the primary concern of a cloud service model. However, a number of significant challenges revealed that cloud environments are not as much secure as one would expect. There is also a limited understanding regarding the offering of secure services in a cloud model that can counter such challenges. This indicates the significance of the fact that what establishes the threat in cloud model. One of the main threats in a cloud model is of cost-effectiveness, normally cloud providers reduce cost by sharing infrastructure between multiple un-trusted VMs. This sharing has also led to several problems including co-location attacks. Cloud providers mitigate co-location attacks by introducing the concept of isolation. Due to this, a guest VM cannot interfere with its host machine, and with other guest VMs running on the same system. Such isolation is one of the prime foundations of cloud security for major public providers. However, such logical boundaries are not impenetrable. A myriad of previous studies have demonstrated how co-resident VMs could be vulnerable to attacks through shared file systems, cache side-channels, or through compromising of hypervisor layer using rootkits. Thus, the threat of cross-VM attacks is still possible because an attacker uses one VM to control or access other VMs on the same hypervisor. Hence, multiple methods are devised for strategic VM placement in order to exploit co-residency. Despite the clear potential for co-location attacks for abusing shared memory and disk, fine grained cross-VM network-channel attacks have not yet been demonstrated. Current network based attacks exploit existing vulnerabilities in networking technologies, such as ARP spoofing and DNS poisoning, which are difficult to use for VM-targeted attacks. The most commonly discussed network-based challenges focus on the fact that cloud providers place more layers of isolation between co-resided VMs than in non-virtualized settings because the attacker and victim are often assigned to separate segmentation of virtual networks. However, it has been demonstrated that this is not necessarily sufficient to prevent manipulation of a victim VM’s traffic. This thesis presents a comprehensive method and empirical analysis on the advancement of co-location attacks in which a malicious VM can negatively affect the security and privacy of other co-located VMs as it breaches the security perimeter of the cloud model. In such a scenario, it is imperative for a cloud provider to be able to appropriately secure access to the data such that it reaches to the appropriate destination. The primary contribution of the work presented in this thesis is to introduce two innovative attack models in leading cloud models, impersonation and privilege escalation, that successfully breach the security perimeter of cloud models and also propose countermeasures that block such types of attacks. The attack model revealed in this thesis, is a combination of impersonation and mirroring. This experimental setting can exploit the network channel of cloud model and successfully redirects the network traffic of other co-located VMs. The main contribution of this attack model is to find a gap in the contemporary network cloud architecture that an attacker can exploit. Prior research has also exploited the network channel using ARP poisoning, spoofing but all such attack schemes have been countered as modern cloud providers place more layers of security features than in preceding settings. Impersonation relies on the already existing regular network devices in order to mislead the security perimeter of the cloud model. The other contribution presented of this thesis is ‘privilege escalation’ attack in which a non-root user can escalate a privilege level by using RoP technique on the network channel and control the management domain through which attacker can manage to control the other co-located VMs which they are not authorized to do so. Finally, a countermeasure solution has been proposed by directly modifying the open source code of cloud model that can inhibit all such attacks

Design Space Exploration and Resource Management of Multi/Many-Core Systems

The increasing demand of processing a higher number of applications and related data on computing platforms has resulted in reliance on multi-/many-core chips as they facilitate parallel processing. However, there is a desire for these platforms to be energy-efficient and reliable, and they need to perform secure computations for the interest of the whole community. This book provides perspectives on the aforementioned aspects from leading researchers in terms of state-of-the-art contributions and upcoming trends

Security in Computer and Information Sciences

This open access book constitutes the thoroughly refereed proceedings of the Second International Symposium on Computer and Information Sciences, EuroCybersec 2021, held in Nice, France, in October 2021. The 9 papers presented together with 1 invited paper were carefully reviewed and selected from 21 submissions. The papers focus on topics of security of distributed interconnected systems, software systems, Internet of Things, health informatics systems, energy systems, digital cities, digital economy, mobile networks, and the underlying physical and network infrastructures. This is an open access book

Cyber-security training: A comparative analysis of cyber-ranges and emerging trends

Οι επιθέσεις στον κυβερνοχώρο γίνονται όλο και πιο προηγμένες και δύσκολα ανιχνεύσιμες, προέρχονται από ποικίλες πήγες και πραγματοποιούνται λαμβάνοντας πολλαπλές διαστάσεις και παίρνοντας διάφορες μορφές. Η ανάγκη οικοδόμησης και πειραματισμού σε προηγμένους μηχανισμούς ασφάλειας στον κυβερνοχώρο, καθώς και η συνεχής κατάρτιση με τη χρήση σύγχρονων μεθοδολογιών, τεχνικών και ενημερωμένων ρεαλιστικών σεναρίων είναι ζωτικής σημασίας. Τα Cyber Ranges μπορούν να προσφέρουν το περιβάλλον μέσα στο οποίο οι ιδικοί και επαγγελματίες στον τομέα της ασφάλειας στον κυβερνοχώρο μπορούν να εφαρμόσουν τεχνικές και δεξιότητες και να εκπαιδεύονται σε προσομοιώσεις σύνθετων δικτύων μεγάλης κλίμακας, προκειμένου να ανταποκριθούν σε πραγματικά σενάρια επίθεσης στον κυβερνοχώρο. Επιπλέον, μπορούν να προσομοιώσουν ένα περιβάλλον για τους επαγγελματίες της ασφάλειας πληροφοριών, να αξιολογήσουν τις διαδικασίες χειρισμού και αντιμετώπισης περιστατικών και να δοκιμάσουν νέες τεχνολογίες, προκειμένου να βοηθήσουν στην πρόληψη επιθέσεων στον κυβερνοχώρο. Κύριος σκοπός της παρούσας εργασίας είναι να περιγράψει τις λειτουργίες διαφόρων Cyber Ranges και να τονίσει τα κύρια δομικά στοιχεία και γνωρίσματα τους, να παρουσιάσει την υψηλού επιπέδου αρχιτεκτονική ενός υπερσύγχρονου Cyber Range και ταυτόχρονα να ταξινομήσει τα χαρακτηριστικά των υπό ανάλυση Cyber Ranges σύμφωνα με τα χαρακτηριστικά του προτεινόμενου.Cyber-attacks are becoming stealthier and more sophisticated can stem from various sources, using multiple vectors and taking different forms. The need for building and experimenting on advanced cyber-security mechanisms, as well as continuous training using state-of-the-art methodologies, techniques and up-to-date realistic scenarios is vital. Cyber Ranges can provide the environment where cyber-security experts and professionals can practice technical and soft skills and be trained on emulated large-scale complex networks in the way to respond to real-world cyber-attack scenarios. Furthermore, they can simulate an environment for information security professionals, to evaluate incident handling and response procedures and to test new technologies, in order to help prevent cyber-attacks. The main objective of this paper is to describe the functionalities of various Cyber Ranges and to highlight their key components and characteristics, to demonstrate a high-level architecture of a state-of-the-art Cyber Range while classifying the features of the reviewed Cyber Ranges according to the attributes of the proposed one

Towards understanding and mitigating attacks leveraging zero-day exploits

Zero-day vulnerabilities are unknown and therefore not addressed with the result that they can be exploited by attackers to gain unauthorised system access. In order to understand and mitigate against attacks leveraging zero-days or unknown techniques, it is necessary to study the vulnerabilities, exploits and attacks that make use of them. In recent years there have been a number of leaks publishing such attacks using various methods to exploit vulnerabilities. This research seeks to understand what types of vulnerabilities exist, why and how these are exploited, and how to defend against such attacks by either mitigating the vulnerabilities or the method / process of exploiting them. By moving beyond merely remedying the vulnerabilities to defences that are able to prevent or detect the actions taken by attackers, the security of the information system will be better positioned to deal with future unknown threats. An interesting finding is how attackers exploit moving beyond the observable bounds to circumvent security defences, for example, compromising syslog servers, or going down to lower system rings to gain access. However, defenders can counter this by employing defences that are external to the system preventing attackers from disabling them or removing collected evidence after gaining system access. Attackers are able to defeat air-gaps via the leakage of electromagnetic radiation as well as misdirect attribution by planting false artefacts for forensic analysis and attacking from third party information systems. They analyse the methods of other attackers to learn new techniques. An example of this is the Umbrage project whereby malware is analysed to decide whether it should be implemented as a proof of concept. Another important finding is that attackers respect defence mechanisms such as: remote syslog (e.g. firewall), core dump files, database auditing, and Tripwire (e.g. SlyHeretic). These defences all have the potential to result in the attacker being discovered. Attackers must either negate the defence mechanism or find unprotected targets. Defenders can use technologies such as encryption to defend against interception and man-in-the-middle attacks. They can also employ honeytokens and honeypots to alarm misdirect, slow down and learn from attackers. By employing various tactics defenders are able to increase their chance of detecting and time to react to attacks, even those exploiting hitherto unknown vulnerabilities. To summarize the information presented in this thesis and to show the practical importance thereof, an examination is presented of the NSA's network intrusion of the SWIFT organisation. It shows that the firewalls were exploited with remote code execution zerodays. This attack has a striking parallel in the approach used in the recent VPNFilter malware. If nothing else, the leaks provide information to other actors on how to attack and what to avoid. However, by studying state actors, we can gain insight into what other actors with fewer resources can do in the future

Using embedded hardware monitor cores in critical computer systems

The integration of FPGA devices in many different architectures and services makes monitoring and real time detection of errors an important concern in FPGA system design. A monitor is a tool, or a set of tools, that facilitate analytic measurements in observing a given system. The goal of these observations is usually the performance analysis and optimisation, or the surveillance of the system. However, System-on-Chip (SoC) based designs leave few points to attach external tools such as logic analysers. Thus, an embedded error detection core that allows observation of critical system nodes (such as processor cores and buses) should enforce the operation of the FPGA-based system, in order to prevent system failures. The core should not interfere with system performance and must ensure timely detection of errors. This thesis is an investigation onto how a robust hardware-monitoring module can be efficiently integrated in a target PCI board (with FPGA-based application processing features) which is part of a critical computing system. [Continues.

Developing a Systematic Process for Mobile Surveying and Analysis of WLAN security

Wireless Local Area Network (WLAN), familiarly known as Wi-Fi, is one of the most used wireless networking technologies. WLANs have rapidly grown in popularity since the release of the original IEEE 802.11 WLAN standard in 1997. We are using our beloved wireless internet connection for everything and are connecting more and more devices into our wireless networks in every form imaginable. As the number of wireless network devices keeps increasing, so does the importance of wireless network security. During its now over twenty-year life cycle, a multitude of various security measures and protocols have been introduced into WLAN connections to keep our wireless communication secure. The most notable security measures presented in the 802.11 standard have been the encryption protocols Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA). Both encryption protocols have had their share of flaws and vulnerabilities, some of them so severe that the use of WEP and the first generation of the WPA protocol have been deemed irredeemably broken and unfit to be used for WLAN encryption. Even though the aforementioned encryption protocols have been long since deemed fatally broken and insecure, research shows that both can still be found in use today. The purpose of this Master’s Thesis is to develop a process for surveying wireless local area networks and to survey the current state of WLAN security in Finland. The goal has been to develop a WLAN surveying process that would at the same time be efficient, scalable, and easily replicable. The purpose of the survey is to determine to what extent are the deprecated encryption protocols used in Finland. Furthermore, we want to find out in what state is WLAN security currently in Finland by observing the use of other WLAN security practices. The survey process presented in this work is based on a WLAN scanning method called Wardriving. Despite its intimidating name, wardriving is simply a form of passive wireless network scanning. Passive wireless network scanning is used for collecting information about the surrounding wireless networks by listening to the messages broadcasted by wireless network devices. To collect our research data, we conducted wardriving surveys on three separate occasions between the spring of 2019 and early spring of 2020, in a typical medium-sized Finnish city. Our survey results show that 2.2% out of the located networks used insecure encryption protocols and 9.2% of the located networks did not use any encryption protocol. While the percentage of insecure networks is moderately low, we observed during our study that private consumers are reluctant to change the factory-set default settings of their wireless network devices, possibly exposing them to other security threats