Biblio

Recent years have seen an exponential growth of the collection and processing of data from heterogeneous sources for a variety of purposes. Several methods and techniques have been proposed to transform and fuse data into "useful" information. However, the security aspects concerning the fusion of sensitive data are often overlooked. This paper investigates the problem of data fusion and derived data control. In particular, we identify the requirements for regulating the fusion process and eliciting restrictions on the access and usage of derived data. Based on these requirements, we propose an attribute-based policy framework to control the fusion of data from different information sources and under the control of different authorities. The framework comprises two types of policies: access control policies, which define the authorizations governing the resources used in the fusion process, and fusion policies, which define constraints on allowed fusion processes. We also discuss how such policies can be obtained for derived data.

With data becoming available in larger quantities and at higher rates, new data processing paradigms have been proposed to handle high-volume, fast-moving data. Data Stream Processing is one such paradigm wherein transient data streams flow through sets of continuous queries, only returning results when data is of interest to the querier. To avoid the large costs associated with maintaining the infrastructure required for processing these data streams, many companies will outsource their computation to third-party cloud services. This outsourcing, however, can lead to private data being accessed by parties that a data provider may not trust. The literature offers solutions to this confidentiality and access control problem but they have fallen short of providing a complete solution to these problems, due to either immense overheads or trust requirements placed on these third-party services. To address these issues, we have developed PolyStream, an enhancement to existing data stream management systems that enables data providers to specify attribute-based access control policies that are cryptographically enforced while simultaneously allowing many types of in-network data processing. We detail the access control models and mechanisms used by PolyStream, and describe a novel use of security punctuations that enables flexible, online policy management and key distribution. We detail how queries are submitted and executed using an unmodified Data Stream Management System, and show through an extensive evaluation that PolyStream yields a 550x performance gain versus the state-of-the-art system StreamForce in CODASPY 2014, while providing greater functionality to the querier.

With data becoming available in larger quantities and at higher rates, new data processing paradigms have been proposed to handle high-volume, fast-moving data. Data Stream Processing is one such paradigm wherein transient data streams flow through sets of continuous queries, only returning results when data is of interest to the querier. To avoid the large costs associated with maintaining the infrastructure required for processing these data streams, many companies will outsource their computation to third-party cloud services. This outsourcing, however, can lead to private data being accessed by parties that a data provider may not trust. The literature offers solutions to this confidentiality and access control problem but they have fallen short of providing a complete solution to these problems, due to either immense overheads or trust requirements placed on these third-party services. To address these issues, we have developed PolyStream, an enhancement to existing data stream management systems that enables data providers to specify attribute-based access control policies that are cryptographically enforced while simultaneously allowing many types of in-network data processing. We detail the access control models and mechanisms used by PolyStream, and describe a novel use of security punctuations that enables flexible, online policy management and key distribution. We detail how queries are submitted and executed using an unmodified Data Stream Management System, and show through an extensive evaluation that PolyStream yields a 550x performance gain versus the state-of-the-art system StreamForce in CODASPY 2014, while providing greater functionality to the querier.

Multi-core is widely used for mobile devices due to high performance and good energy efficiency. For maintaining cores' cache coherency, mobile multi-core integrated new hardware ARM CCI. In this study, we focus on the security aspect of mobile multi-core. We monitor cache coherency operations that occur among PSL related processes' inter-core communication. After simple analysis, we can sneak android PSL information. Some preliminary results show that we could efficiently identify PSL pattern. This is a significant security violation in terms of confidentiality. In addition, mobile multi-cores are already prevalent, the attack is practical, and it can be easily spread.

Kernel rootkits often hide associated malicious processes by altering reported task struct information to upper layers and applications such as ps and top. Virtualized settings offer a unique opportunity to mitigate this behavior using dynamic virtual machine introspection (VMI). For known kernels, VMI can be deployed to search for kernel objects and identify them by using unique data structure "signatures". In existing work, VMI-detected data structure signatures are based on values and structural features which must be (often exactly) present in memory snapshots taken, for accurate detection. This features a certain brittleness and rootkits can escape detection by simply temporarily "un-tangling" the corresponding structures when not running. Here we introduce a new paradigm, that defeats such behavior by training for and observing signatures of timing access patterns to any and all kernel-mapped data regions, including objects that are not directly linked in the "official" list of tasks. The use of timing information in training detection signatures renders the defenses resistant to attacks that try to evade detection by removing their corresponding malicious processes before scans. KXRay successfully detected processes hidden by four traditional rootkits.

In recent years, the number of new examples of malware has continued to increase. To create effective countermeasures, security specialists often must manually inspect vast sandbox logs produced by the dynamic analysis method. Conversely, antivirus vendors usually publish malware analysis reports on their website. Because malware analysis reports and sandbox logs do not have direct connections, when analyzing sandbox logs, security specialists can not benefit from the information described in such expert reports. To address this issue, we developed a system called ReGenerator that automates the generation of reports related to sandbox logs by making use of existing reports published by antivirus vendors. Our system combines several techniques, including the Jaccard similarity, Natural Language Processing (NLP), and Generation (NLG), to produce concise human-readable reports describing malicious behavior for security specialists.

This paper presents a new type of online password guessing attack called "WiPING" (Wi-Fi signal-based PIN Guessing attack) to guess a victim's PIN (Personal Identification Number) within a small number of unlock attempts. WiPING uses wireless signal patterns identified from observing sequential finger movements involved in typing a PIN to unlock a mobile device. A list of possible PIN candidates is generated from the wireless signal patterns, and is used to improve performance of PIN guessing attacks. We implemented a proof-of-concept attack to demonstrate the feasibility of WiPING. Our results showed that WiPING could be practically effective: while pure guessing attacks failed to guess all 20 PINs, WiPING successfully guessed two PINs.

Continuing progress and integration levels in silicon technologies make possible complete end-user systems consisting of extremely high number of cores on a single chip targeting either embedded or high-performance computing. However, without new paradigms of energy- and thermally-efficient designs, producing information and communication systems capable of meeting the computing, storage and communication demands of the emerging applications will be unlikely. The broad topic of power and thermal management of massive multicore chips is actively being pursued by a number of researchers worldwide, from a variety of different perspectives, ranging from workload modeling to efficient on-chip network infrastructure design to resource allocation. Successful solutions will likely adopt and encompass elements from all or at least several levels of abstraction. Starting from these ideas, we consider a holistic approach in establishing the Power-Thermal-Performance (PTP) trade-offs of massive multicore processors by considering three inter-related but varying angles, viz., on-chip traffic modeling, novel Networks-on-Chip (NoC) architecture and resource allocation/mapping On-line workload (mathematical modeling, analysis and prediction) learning is fundamental for endowing the many-core platforms with self-optimizing capabilities [2][3]. This built-in intelligence capability of many-cores calls for monitoring the interactions between the set of running applications and the architectural (core and uncore) components, the online construction of mathematical models for the observed workloads, and determining the best resource allocation decisions given the limited amount of information about user-to-application-to-system dynamics. However, workload modeling is not a trivial task. Centralized approaches for analyzing and mining workloads can easily run into scalability issues with increasing number of monitored processing elements and uncore (routers and interface queues) components since it can either lead to significant traffic and energy overhead or require dedicated system infrastructure. In contrast, learning the most compact mathematical representation of the workload can be done in a distributed manner (within the proximity of the observation /sensing) as long as the mathematical techniques are flexible and exploit the mathematical characteristics of the workloads (degree of periodicity, degree of fractal and temporal scaling) [3]. As one can notice, this strategy does not postulate a-priori the mathematical expressions (e.g., a specific order of the autoregressive moving average (ARMA) model). Instead, the periodicity and fractality of the observed computation (e.g., instructions per cycles, last level cache misses, branch prediction successes and failures, TLB access/misses) and communication (request-reply latency, queues utilization, memory queuing delay) metrics dictate the number of coefficients, the linearity or nonlinearity of the dynamical state equations and the noise terms (e.g., Gaussian distributed) [3]. In other words, dedicated minimal logic can be allocated to interact with the local sensor to analyze the incoming workload at run-time, determine the required number of parameters and their values as a function of their characteristics and communicate only the workload model parameters to a hierarchical optimization module (autonomous control architecture). For instance, capturing the fractal characteristics of the core and uncore workloads led to the development of more efficient power management strategy [1] than those based on PID or model predictive control. In order to develop a compact and accurate mathematical framework for analyzing and modeling the incoming workload, we describe a general probabilistic approach that models the statistics of the increments in the magnitude of a stochastic process (associated with a specific workload metric) and the intervals of time (inter-event times) between successive changes in the stochastic process [3]. We show that the statistics of these two components of the stochastic process allows us to derive state equations and capture either short-range or long-range memory properties. To test the benefits of this new workload modeling approach, we describe its integration into a multi-fractal optimal control framework for solving the power management for a 64-core NoC-based manycore platform and contrast it with a mono-fractal and non-fractal schemes [3]. A scalable, low power, and high-bandwidth on-chip communication infrastructure is essential to sustain the predicted growth in the number of embedded cores in a single die. New interconnection fabrics are key for continued performance improvements and energy reduction of manycore chips, and an efficient and robust NoC architecture is one of the key steps towards achieving that goal. An NoC architecture that incorporates emerging interconnect paradigms will be an enabler for low-power, high-bandwidth manycore chips. Innovative interconnect paradigms based on optical technologies, RF/wireless methods, carbon nanotubes, or 3D integration are promising alternatives that may indeed overcome obstacles that impede continued advances of the manycore paradigm. These innovations will open new opportunities for research in NoC designs with emerging interconnect infrastructures. In this regard, wireless NoC (WiNoC) is a promising direction to design energy efficient multicore architectures. WiNoC not only helps in improving the energy efficiency and performance, it also opens up opportunities for implementing power management strategies. WiNoCs enable implementation of the two most popular power management mechanisms, viz., dynamic voltage and frequency scaling (DVFS) and voltage frequency island (VFI). The wireless links in the WiNoC establish one-hop shortcuts between the distant nodes and facilitate energy savings in data exchange [3]. The wireless shortcuts attract a significant amount of the overall traffic within the network. The amount of traffic detoured is substantial and the low power wireless links enable energy savings. However, the overall energy dissipation within the network is still dominated by the data traversing the wireline links. Hence, by incorporating DVFS on these wireline links we can save more energy. Moreover, by incorporating suitable congestion aware routing with DVFS, we can avoid thermal hotspots in the system [4]. It should be noted that for large system size the hardware overhead in terms of on-chip voltage regulators and synchronizers is much more in DVFS than in VFI. WiNoC-enabled VFI designs mitigate some of the full-system performance degradation inherent in VFI-partitioned multicore designs, and it also help in eliminating it entirely for certain applications [5]. The VFI-partitioned designs used in conjunction with a novel NoC architecture like WiNoC can achieve significant energy savings while minimizing the impact on the achievable performance. On-chip power density and temperature trends are continuously increasing due to high integration density of nano-scale transistors and failure of Dennard Scaling as a result of diminishing voltage scaling. Hence, all computing is temperature-constrained computing and therefore, employing thermal management techniques that keep chip temperatures within safe limits along with meeting the constraints of spatial/temporal thermal gradients and avoid wear-out effects [8] is key. We introduced the novel concept of Dark Silicon Patterning, i.e. spatio-temporal control of power states of different cores [9] Sophisticated patterning and thread-to-core mapping decisions are made considering the knowledge of process variations and lateral heat dissipation of power-gated cores in order to enhance the performance of multi-threaded workloads through dynamic core count scaling (DCCS). This is enabled by a lightweight online prediction of chip's thermal profile for a given patterning candidate. We also present an enhanced temperature-aware resource management technique that, besides active and dark states of cores, also exploit various grey states (i.e., using different voltage-frequency levels) in order to achieve a high performance for mixed ILP-TLP workloads under peak temperature constraints. High ILP applications benefit from high V-f and boosting levels, while high TLP applications benefit from As the scaling trends move from multi-core to many-core processors, the centralized solutions become infeasible, and thereby require distributed techniques. In [6], we proposed an agent-based distributed temperature-aware resource management technique called TAPE. It assigns a so-called agent to each core, a software or hardware entity that acts on behalf of the core. Following the principles of economic theory, these agents negotiate with each other to trade their power budgets in order to fulfil the performance requirements of their tasks, while keep the TPeak≤Tcritical. In case of thermal violations, task migration or V-f throttling is triggered, and a penalty is applied to the trading process to improve the decision making.

Cyber Physical Systems (CPS) security testbeds serve as a platform for evaluating and validating novel CPS security tools and technologies, accelerating the transition of state-of-the-art research to industrial practice. The engineering of CPS security testbeds requires significant investments in money, time and modeling efforts to provide a scalable, high-fidelity, real-time attack-defense platform. Therefore, there is a strong need in academia and industry to create remotely accessible testbeds that support a range of use-cases pertaining to CPS security of the grid, including vulnerability assessments, impact analysis, product testing, attack-defense exercises, and operator training. This paper describes the implementation architecture, and capabilities of a remote access and experimental orchestration framework developed for the PowerCyber CPS security testbed at Iowa State University (ISU). The paper then describes several engineering challenges in the development of such remotely accessible testbeds for Smart Grid CPS security experimentation. Finally, the paper provides a brief case study with some screenshots showing a particular use case scenario on the remote access framework.

In cloud computing, computationally weak users are always willing to outsource costly computations to a cloud, and at the same time they need to check the correctness of the result provided by the cloud. Such activities motivate the occurrence of verifiable computation (VC). Recently, Parno, Raykova and Vaikuntanathan showed any VC protocol can be constructed from an attribute-based encryption (ABE) scheme for a same class of functions. In this paper, we propose two practical and efficient semi-adaptively secure key-policy attribute-based encryption (KP-ABE) schemes with constant-size ciphertexts. The semi-adaptive security requires that the adversary designates the challenge attribute set after it receives public parameters but before it issues any secret key query, which is stronger than selective security guarantee. Our first construction deals with small universe while the second one supports large universe. Both constructions employ the technique underlying the prime-order instantiation of nested dual system groups, which are based on the \$d\$-linear assumption including SXDH and DLIN assumptions. In order to evaluate the performance, we implement our ABE schemes using \$\textbackslashtextsf\Python\\$ language in Charm. Compared with previous KP-ABE schemes with constant-size ciphertexts, our constructions achieve shorter ciphertext and secret key sizes, and require low computation costs, especially under the SXDH assumption.

In cloud computing, computationally weak users are always willing to outsource costly computations to a cloud, and at the same time they need to check the correctness of the result provided by the cloud. Such activities motivate the occurrence of verifiable computation (VC). Recently, Parno, Raykova and Vaikuntanathan showed any VC protocol can be constructed from an attribute-based encryption (ABE) scheme for a same class of functions. In this paper, we propose two practical and efficient semi-adaptively secure key-policy attribute-based encryption (KP-ABE) schemes with constant-size ciphertexts. The semi-adaptive security requires that the adversary designates the challenge attribute set after it receives public parameters but before it issues any secret key query, which is stronger than selective security guarantee. Our first construction deals with small universe while the second one supports large universe. Both constructions employ the technique underlying the prime-order instantiation of nested dual system groups, which are based on the \$d\$-linear assumption including SXDH and DLIN assumptions. In order to evaluate the performance, we implement our ABE schemes using \$\textbackslashtextsf\Python\\$ language in Charm. Compared with previous KP-ABE schemes with constant-size ciphertexts, our constructions achieve shorter ciphertext and secret key sizes, and require low computation costs, especially under the SXDH assumption.

We study a sensor network setting in which samples are encrypted individually using different keys and maintained on a cloud storage. For large systems, e.g. those that generate several millions of samples per day, fine-grained sharing of encrypted samples is challenging. Existing solutions, such as Attribute-Based Encryption (ABE) and Key Aggregation Cryptosystem (KAC), can be utilized to address the challenge, but only to a certain extent. They are often computationally expensive and thus unlikely to operate at scale. We propose an algorithmic enhancement and two heuristics to improve KAC's key reconstruction cost, while preserving its provable security. The improvement is particularly significant for range and down-sampling queries – accelerating the reconstruction cost from quadratic to linear running time. Experimental study shows that for queries of size 32k samples, the proposed fast reconstruction techniques speed-up the original KAC by at least 90 times on range and down-sampling queries, and by eight times on general (arbitrary) queries. It also shows that at the expense of splitting the query into 16 sub-queries and correspondingly issuing that number of different aggregated keys, reconstruction time can be reduced by 19 times. As such, the proposed techniques make KAC more applicable in practical scenarios such as sensor networks or the Internet of Things.

We study a sensor network setting in which samples are encrypted individually using different keys and maintained on a cloud storage. For large systems, e.g. those that generate several millions of samples per day, fine-grained sharing of encrypted samples is challenging. Existing solutions, such as Attribute-Based Encryption (ABE) and Key Aggregation Cryptosystem (KAC), can be utilized to address the challenge, but only to a certain extent. They are often computationally expensive and thus unlikely to operate at scale. We propose an algorithmic enhancement and two heuristics to improve KAC's key reconstruction cost, while preserving its provable security. The improvement is particularly significant for range and down-sampling queries – accelerating the reconstruction cost from quadratic to linear running time. Experimental study shows that for queries of size 32k samples, the proposed fast reconstruction techniques speed-up the original KAC by at least 90 times on range and down-sampling queries, and by eight times on general (arbitrary) queries. It also shows that at the expense of splitting the query into 16 sub-queries and correspondingly issuing that number of different aggregated keys, reconstruction time can be reduced by 19 times. As such, the proposed techniques make KAC more applicable in practical scenarios such as sensor networks or the Internet of Things.

Devices in the internet of things (IoT) are frequently (i) resource-constrained, and (ii) deployed in unmonitored, physically unsecured environments. Securing these devices requires tractable cryptographic protocols, as well as cost effective tamper resistance solutions. We propose and evaluate cryptographic protocols that leverage physical unclonable functions (PUFs): circuits whose input to output mapping depends on the unique characteristics of the physical hardware on which it is executed. PUF-based protocols have the benefit of minimizing private key exposure, as well as providing cost-effective tamper resistance. We present and experimentally evaluate an elliptic curve based variant of a theoretical PUF-based authentication protocol proposed previously in the literature. Our work improves over an existing proof-of-concept implementation, which relied on the discrete logarithm problem as proposed in the original work. In contrast, our construction uses elliptic curve cryptography, which substantially reduces the computational and storage burden on the device. We describe PUF-based algorithms for device enrollment, authentication, decryption, and digital signature generation. The performance of each construction is experimentally evaluated on a resource-constrained device to demonstrate tractability in the IoT domain. We demonstrate that our implementation achieves practical performance results, while also providing realistic security. Our work demonstrates that PUF-based protocols may be practically and securely deployed on low-cost resource-constrained IoT devices.

This work deals with key generation based on Physically Obfuscated Keys (POKs), i.e., a certain type of tamper-evident Physical Unclonable Function (PUF) that can be used as protection against invasive physical attacks. To design a protected device, one must take attacks such as probing of data lines or penetration of the physical security boundary into consideration. For the implementation of a POK as a countermeasure, physical properties of a material – which covers all parts to be protected – are measured. After measuring these properties, i.e. analog values, they have to be quantized in order to derive a cryptographic key. This paper will present and discuss the impact of the quantization method with regard to three parameters: key quality, tamper-sensitivity, and reliability. Our contribution is the analysis of two different quantization schemes considering these parameters. Foremost, we propose a new approach to achieve improved tamper-sensitivity in the worst-case with no information leakage. We then analyze a previous solution and compare it to our scenario. Based on empirical data we demonstrate the advantages of our approach. This significantly improves the level of protection of a tamper-resistant cryptographic device compared to cases not benefiting from our scheme.

With the prevalence of personal Bluetooth devices, potential breach of user privacy has been an increasing concern. To date, sniffing Bluetooth traffic has been widely considered an extremely intricate task due to Bluetooth's indiscoverable mode, vendor-dependent adaptive hopping behavior, and the interference in the open 2.4 GHz band. In this paper, we present BlueEar -a practical Bluetooth traffic sniffer. BlueEar features a novel dual-radio architecture where two Bluetooth-compliant radios coordinate with each other on learning the hopping sequence of indiscoverable Bluetooth networks, predicting adaptive hopping behavior, and mitigating the impacts of RF interference. Experiment results show that BlueEar can maintain a packet capture rate higher than 90% consistently in real-world environments, where the target Bluetooth network exhibits diverse hopping behaviors in the presence of dynamic interference from coexisting Wi-Fi devices. In addition, we discuss the privacy implications of the BlueEar system, and present a practical countermeasure that effectively reduces the packet capture rate of the sniffer to 20%. The proposed countermeasure can be easily implemented on the Bluetooth master device while requiring no modification to slave devices like keyboards and headsets.

Pseudo-random number generators (PRNGs) are a critical infrastructure for cryptography and security of many computer applications. At the same time, PRNGs are surprisingly difficult to design, implement, and debug. This paper presents the first static analysis technique specifically for quality assurance of cryptographic PRNG implementations. The analysis targets a particular kind of implementation defect, the entropy loss. Entropy loss occurs when the entropy contained in the PRNG seed is not utilized to the full extent for generating the pseudo-random output stream. The Debian OpenSSL disaster, probably the most prominent PRNG-related security incident, was one but not the only manifestation of such a defect. Together with the static analysis technique, we present its implementation, a tool named Entroposcope. The tool offers a high degree of automation and practicality. We have applied the tool to five real-world PRNGs of different designs and show that it effectively detects both known and previously unknown instances of entropy loss.

We consider a data owner that outsources its dataset to an untrusted server. The owner wishes to enable the server to answer range queries on a single attribute, without compromising the privacy of the data and the queries. There are several schemes on "practical" private range search (mainly in Databases venues) that attempt to strike a trade-off between efficiency and security. Nevertheless, these methods either lack provable security guarantees, or permit unacceptable privacy leakages. In this paper, we take an interdisciplinary approach, which combines the rigor of Security formulations and proofs with efficient Data Management techniques. We construct a wide set of novel schemes with realistic security/performance trade-offs, adopting the notion of Searchable Symmetric Encryption (SSE) primarily proposed for keyword search. We reduce range search to multi-keyword search using range covering techniques with tree-like indexes. We demonstrate that, given any secure SSE scheme, the challenge boils down to (i) formulating leakages that arise from the index structure, and (ii) minimizing false positives incurred by some schemes under heavy data skew. We analytically detail the superiority of our proposals over prior work and experimentally confirm their practicality.

This paper presents implementation results of several side channel countermeasures for protecting the scalar multiplication of ECC (Elliptic Curve Cryptography) implemented on an ARM Cortex M3 processor that is used in security sensitive wireless sensor nodes. Our implementation was done for the ECC curves P-256, brainpool256r1, and Ed25519. Investigated countermeasures include Double-And-Add Always, Montgomery Ladder, Scalar Randomization, Randomized Scalar Splitting, Coordinate Randomization, and Randomized Sliding Window. Practical side channel tests for SEMA (Simple Electromagnetic Analysis) and MESD (Multiple Exponent, Single Data) are included. Though more advanced side channel attacks are not evaluated, yet, our results show that an appropriate level of resistance against the most relevant attacks can be reached.

Digital signatures are perhaps the most important base for authentication and trust relationships in large scale systems. More specifically, various applications of signatures provide privacy and anonymity preserving mechanisms and protocols, and these, in turn, are becoming critical (due to the recently recognized need to protect individuals according to national rules and regulations). A specific type of signatures called "signatures with efficient protocols", as introduced by Camenisch and Lysyanskaya (CL), efficiently accommodates various basic protocols and extensions like zero-knowledge proofs, signing committed messages, or re-randomizability. These are, in fact, typical operations associated with signatures used in typical anonymity and privacy-preserving scenarios. To date there are no "signatures with efficient protocols" which are based on simple assumptions and truly practical. These two properties assure us a robust primitive: First, simple assumptions are needed for ensuring that this basic primitive is mathematically robust and does not require special ad hoc assumptions that are more risky, imply less efficiency, are more tuned to the protocol itself, and are perhaps less trusted. In the other dimension, efficiency is a must given the anonymity applications of the protocol, since without proper level of efficiency the future adoption of the primitives is always questionable (in spite of their need). In this work, we present a new CL-type signature scheme that is re-randomizable under a simple, well-studied, and by now standard, assumption (SXDH). The signature is efficient (built on the recent QA-NIZK constructions), and is, by design, suitable to work in extended contexts that typify privacy settings (like anonymous credentials, group signature, and offline e-cash). We demonstrate its power by presenting practical protocols based on it.

Here we model the indirect costs of deploying security controls in small-to-medium enterprises (SMEs) to manage cyber threats. SMEs may not have the in-house skills and collective capacity to operate controls efficiently, resulting in inadvertent data leakage and exposure to compromise. Aside from financial costs, attempts to maintain security can impact morale, system performance, and retraining requirements, which are modelled here. Managing the overall complexity and effectiveness of an SME's security controls has the potential to reduce unintended leakage. The UK Cyber Essentials Scheme informs basic control definitions, and Available Responsibility Budget (ARB) is modelled to understand how controls can be prioritised for both security and usability. Human factors of security and practical experience of security management for SMEs inform the modelling of deployment challenges across a set of SME archetypes differing in size, complexity, and use of IT. Simple combinations of controls are matched to archetypes, balancing capabilities to protect data assets with the effort demands placed upon employees. Experiments indicate that two-factor authentication can be readily adopted by many SMEs and their employees to protect core assets, followed by correct access privileges and anti-malware software. Service and technology providers emerge as playing an important role in improving access to usable security controls for SMEs.

As everyone knows vulnerability detection is a very difficult and time consuming work, so taking advantage of the unlabeled data sufficiently is needed and helpful. According the above reality, in this paper a method is proposed to predict buffer overflow based on semi-supervised learning. We first employ Antlr to extract AST from C/C++ source files, then according to the 22 buffer overflow attributes taxonomies, a 22-dimension vector is extracted from every function in AST, at last, the vector is leveraged to train a classifier to predict buffer overflow vulnerabilities. The experiment and evaluation indicate our method is correct and efficient.

Modern operating systems use hardware support to protect against control-flow hijacking attacks such as code-injection attacks. Typically, write access to executable pages is prevented and kernel mode execution is restricted to kernel code pages only. However, current CPUs provide no protection against code-reuse attacks like ROP. ASLR is used to prevent these attacks by making all addresses unpredictable for an attacker. Hence, the kernel security relies fundamentally on preventing access to address information. We introduce Prefetch Side-Channel Attacks, a new class of generic attacks exploiting major weaknesses in prefetch instructions. This allows unprivileged attackers to obtain address information and thus compromise the entire system by defeating SMAP, SMEP, and kernel ASLR. Prefetch can fetch inaccessible privileged memory into various caches on Intel x86. It also leaks the translation-level for virtual addresses on both Intel x86 and ARMv8-A. We build three attacks exploiting these properties. Our first attack retrieves an exact image of the full paging hierarchy of a process, defeating both user space and kernel space ASLR. Our second attack resolves virtual to physical addresses to bypass SMAP on 64-bit Linux systems, enabling ret2dir attacks. We demonstrate this from unprivileged user programs on Linux and inside Amazon EC2 virtual machines. Finally, we demonstrate how to defeat kernel ASLR on Windows 10, enabling ROP attacks on kernel and driver binary code. We propose a new form of strong kernel isolation to protect commodity systems incuring an overhead of only 0.06-5.09%.

Malware evolves perpetually and relies on increasingly so- phisticated attacks to supersede defense strategies. Data-driven approaches to malware detection run the risk of becoming rapidly antiquated. Keeping pace with malware requires models that are periodically enriched with fresh knowledge, commonly known as retraining. In this work, we propose the use of Venn-Abers predictors for assessing the quality of binary classification tasks as a first step towards identifying antiquated models. One of the key benefits behind the use of Venn-Abers predictors is that they are automatically well calibrated and offer probabilistic guidance on the identification of nonstationary populations of malware. Our framework is agnostic to the underlying classification algorithm and can then be used for building better retraining strategies in the presence of concept drift. Results obtained over a timeline-based evaluation with about 90K samples show that our framework can identify when models tend to become obsolete.

New hardware primitives such as Intel SGX secure a user-level process in presence of an untrusted or compromised OS. Such "enclaved execution" systems are vulnerable to several side-channels, one of which is the page fault channel. In this paper, we show that the page fault side-channel has sufficient channel capacity to extract bits of encryption keys from commodity implementations of cryptographic routines in OpenSSL and Libgcrypt – leaking 27% on average and up to 100% of the secret bits in many case-studies. To mitigate this, we propose a software-only defense that masks page fault patterns by determinising the program's memory access behavior. We show that such a technique can be built into a compiler, and implement it for a subset of C which is sufficient to handle the cryptographic routines we study. This defense when implemented generically can have significant overhead of up to 4000X, but with help of developer-assisted compiler optimizations, the overhead reduces to at most 29.22% in our case studies. Finally, we discuss scope for hardware-assisted defenses, and show one solution that can reduce overheads to 6.77% with support from hardware changes.