Biblio

Many attacks target vulnerabilities of home IoT devices, such as bugs in outdated software and weak passwords. The home network is at a vantage point for deploying security appliances to deal with such IoT attacks. We propose a comprehensive home network defense, Pot2DPI, and use it to raise an attacker's uncertainty about devices and enable the home network to monitor traffic, detect anomalies, and filter malicious packets. The security offered by Pot2DPI comes from a synthesis of practical techniques: honeypot, deep packet inspection (DPI), and a realization of moving target defense (MTD) in port forwarding. In particular, Pot2DPI has a chain of honeypot and DPI that collects suspicious packet traces, acquires attack signatures, and installs filtering rules at a home router timely. Meanwhile, Pot2DPI shuffles the mapping of ports between the router and the devices connected to it, making a targeted attack difficult and defense more effective. Pot2DPI is our first step towards securing a smart home.

The increasing growth of cybercrimes targeting mobile devices urges an efficient malware analysis platform. With the emergence of evasive malware, which is capable of detecting that it is being analyzed in virtualized environments, bare-metal analysis has become the definitive resort. Existing works mainly focus on extracting the malicious behaviors exposed during bare-metal analysis. However, after malware analysis, it is equally important to quickly restore the system to a clean state to examine the next sample. Unfortunately, state-of-the-art solutions on mobile platforms can only restore the disk, and require a time-consuming system reboot. In addition, all of the existing works require some in-guest components to assist the restoration. Therefore, a kernel-level malware is still able to detect the presence of the in-guest components. We propose Bolt, a transparent restoration mechanism for bare-metal analysis on mobile platform without rebooting. Bolt achieves a reboot-less restoration by simultaneously making a snapshot for both the physical memory and the disk. Memory snapshot is enabled by an isolated operating system (BoltOS) in the ARM TrustZone secure world, and disk snapshot is accomplished by a piece of customized firmware (BoltFTL) for flash-based block devices. Because both the BoltOS and the BoltFTL are isolated from the guest system, even kernel-level malware cannot interfere with the restoration. More importantly, Bolt does not require any modifications into the guest system. As such, Bolt is the first that simultaneously achieves efficiency, isolation, and stealthiness to recover from infection due to malware execution. We have implemented a Bolt prototype working with the Android OS. Experimental results show that Bolt can restore the guest system to a clean state in only 2.80 seconds.

The quantity of information that is collected and stored in computer systems continues to grow rapidly. At the same time, the sensitivity of such information (e.g., detailed medical records) often makes such information valuable to both external attackers, who may obtain information by compromising a system, and malicious insiders, who may misuse information by exercising their authorization. To mitigate compromises and deter misuse, the security administrators of these resources often deploy various types of intrusion and misuse detection systems, which provide alerts of suspicious events that are worthy of follow-up review. However, in practice, these systems may generate a large number of false alerts, wasting the time of investigators. Given that security administrators have limited budget for investigating alerts, they must prioritize certain types of alerts over others. An important challenge in alert prioritization is that adversaries may take advantage of such behavior to evade detection - specifically by mounting attacks that trigger alerts that are less likely to be investigated. In this paper, we model alert prioritization with adaptive adversaries using a Stackelberg game and introduce an approach to compute the optimal prioritization of alert types. We evaluate our approach using both synthetic data and a real-world dataset of alerts generated from the audit logs of an electronic medical record system in use at a large academic medical center.

This article derives trade-offs between three basic costs of a parallel algorithm: synchronization, data movement, and computational cost. These trade-offs are lower bounds on the execution time of the algorithm that are independent of the number of processors but dependent on the problem size. Therefore, they provide lower bounds on the execution time of any parallel schedule of an algorithm computed by a system composed of any number of homogeneous processors, each with associated computational, communication, and synchronization costs. We employ a theoretical model that measures the amount of work and data movement as a maximum over that incurred along any execution path during the parallel computation. By considering this metric rather than the total communication volume over the whole machine, we obtain new insights into the characteristics of parallel schedules for algorithms with nontrivial dependency structures. We also present reductions from BSP and LogGP algorithms to our execution model, extending our lower bounds to these two models of parallel computation. We first develop our results for general dependency graphs and hypergraphs based on their expansion properties, and then we apply the theorem to a number of specific algorithms in numerical linear algebra, namely triangular substitution, Cholesky factorization, and stencil computations. We represent some of these algorithms as families of dependency graphs. We derive their communication lower bounds by studying the communication requirements of the hypergraph structures shared by these dependency graphs. In addition to these lower bounds, we introduce a new communication-efficient parallelization for stencil computation algorithms, which is motivated by results of our lower bound analysis and the properties of previously existing parallelizations of the algorithms.

In the minimum Multicut problem, the input is an edge-weighted supply graph G = (V, E) and a demand graph H = (V, F). Either G and H are directed (Dir-MulC) or both are undirected (Undir-MulC). The goal is to remove a minimum weight set of supply edges E' $\subseteq$ E such that in G - E' there is no path from s to t for any demand edge (s, t) $ın$ F. Undir-MulC admits O(log k)-approximation where k is the number of edges in H while the best known approximation for Dir-MulC is min\k, Õ(textbarVtextbar11/23)\. These approximations are obtained by proving corresponding results on the multicommodity flow-cut gap. In this paper we consider the role that the structure of the demand graph plays in determining the approximability of Multicut. We obtain several new positive and negative results. In undirected graphs our main result is a 2-approximation in nO(t) time when the demand graph excludes an induced matching of size t. This gives a constant factor approximation for a specific demand graph that motivated this work, and is based on a reduction to uniform metric labeling and not via the flow-cut gap. In contrast to the positive result for undirected graphs, we prove that in directed graphs such approximation algorithms can not exist. We prove that, assuming the Unique Games Conjecture (UGC), that for a large class of fixed demand graphs Dir-MulC cannot be approximated to a factor better than the worst-case flow-cut gap. As a consequence we prove that for any fixed k, assuming UGC, Dir-MulC with k demand pairs is hard to approximate to within a factor better than k. On the positive side, we obtain a k approximation when the demand graph excludes certain graphs as an induced subgraph. This generalizes the known 2 approximation for directed Multiway Cut to a larger class of demand graphs.

Hidden Markov Models (HMM) are probabilistic models that can be used for forecasting time series data. It has seen success in various domains like finance [1-5], bioinformatics [6-8], healthcare [9-11], agriculture [12-14], artificial intelligence[15-17]. However, the use of HMM in cyber security found to date is numbered. We believe the properties of HMM being predictive, probabilistic, and its ability to model different naturally occurring states form a good basis to model cyber security data. It is hence the motivation of this work to provide the initial results of our attempts to predict security attacks using HMM. A large network datasets representing cyber security attacks have been used in this work to establish an expert system. The characteristics of attacker's IP addresses can be extracted from our integrated datasets to generate statistical data. The cyber security expert provides the weight of each attribute and forms a scoring system by annotating the log history. We applied HMM to distinguish between a cyber security attack, unsure and no attack by first breaking the data into 3 cluster using Fuzzy K mean (FKM), then manually label a small data (Analyst Intuition) and finally use HMM state-based approach. By doing so, our results are very encouraging as compare to finding anomaly in a cyber security log, which generally results in creating huge amount of false detection.

Phishing emails have affected users seriously due to the enormous increasing in numbers and exquisite camouflage. Users spend much more effort on distinguishing the email properties, therefore current phishing email detection system demands more creativity and consideration in filtering for users. The proposed research tries to adopt creative computing in detecting phishing emails for users through a combination of computing techniques and social engineering concepts. In order to achieve the proposed target, the fraud type is summarised in social engineering criteria through literature review; a semantic web database is established to extract and store information; a fuzzy logic control algorithm is constructed to allocate email categories. The proposed approach will help users to distinguish the categories of emails, furthermore, to give advice based on different categories allocation. For the purpose of illustrating the approach, a case study will be presented to simulate a phishing email receiving scenario.

The best practice to prevent Cross Site Scripting (XSS) attacks is to apply encoders to sanitize untrusted data. To balance security and functionality, encoders should be applied to match the web page context, such as HTML body, JavaScript, and style sheets. A common programming error is the use of a wrong encoder to sanitize untrusted data, leaving the application vulnerable. We present a security unit testing approach to detect XSS vulnerabilities caused by improper encoding of untrusted data. Unit tests for the XSS vulnerability are automatically constructed out of each web page and then evaluated by a unit test execution framework. A grammar-based attack generator is used to automatically generate test inputs. We evaluate our approach on a large open source medical records application, demonstrating that we can detect many 0-day XSS vulnerabilities with very low false positives, and that the grammar-based attack generator has better test coverage than industry best practices.

We consider an underlay cognitive network with secondary users that support full-duplex communication. In this context, we propose the application of antenna selection at the secondary destination node to improve the secondary user secrecy performance. Antenna selection rules for cases where exact and average knowledge of the eavesdropping channels are investigated. The secrecy outage probabilities for the secondary eavesdropping network are analyzed, and it is shown that the secrecy performance improvement due to antenna selection is due to coding gain rather than diversity gain. This is very different from classical antenna selection for data transmission, which usually leads to a higher diversity gain. Numerical simulations are included to verify the performance of the proposed scheme.

In this paper we present results of a research on automatic extremist text detection. For this purpose an experimental dataset in the Russian language was created. According to the Russian legislation we cannot make it publicly available. We compared various classification methods (multinomial naive Bayes, logistic regression, linear SVM, random forest, and gradient boosting) and evaluated the contribution of differentiating features (lexical, semantic and psycholinguistic) to classification quality. The results of experiments show that psycholinguistic and semantic features are promising for extremist text detection.

Wearable devices for fitness tracking and health monitoring have gained considerable popularity and become one of the fastest growing smart devices market. More and more companies are offering integrated health and activity monitoring solutions for fitness trackers. Recently insurances are offering their customers better conditions for health and condition monitoring. However, the extensive sensitive information collected by tracking products and accessibility by third party service providers poses vital security and privacy challenges on the employed solutions. In this paper, we present our security analysis of a representative sample of current fitness tracking products on the market. In particular, we focus on malicious user setting that aims at injecting false data into the cloud-based services leading to erroneous data analytics. We show that none of these products can provide data integrity, authenticity and confidentiality.

This paper introduces a multi-factors security key generation mechanism for self-organising Internet of Things (IoT) network and nodes. The mechanism enables users to generate unique set of security keys to enhance IoT security while meeting various business needs. The multi-factor security keys presents an additional security layer to existing security standards and practices currently being adopted by the IoT community. The proposed security key generation mechanism enables user to define and choose any physical and logical parameters he/she prefers, in generating a set of security keys to be encrypted and distributed to registered IoT nodes. IoT applications and services will only be activated after verifying that all security keys are present. Multiple levels of authorisation for different user groups can be easily created through the mix and match of the generated multi-factors security keys. A use case, covering indoor and outdoor field tests was conducted. The results of the tests showed that the mechanism is easily adaptable to meet diverse multivendor IoT devices and is scalable for various applications.

The increasing demand for secure interactions between network domains brings in new challenges to access control technologies. In this paper we design an access control framework which provides a multilevel mapping method between hierarchical access control structures for achieving multilevel security protection in cross-domain networks. Hierarchical access control structures ensure rigorous multilevel security in intra domains. And the mapping method based on subject attributes is proposed to determine the subject's security level in its target domain. Experimental results we obtained from simulations are also reported in this paper to verify the effectiveness of the proposed access control model.

Customers need to know how reliable a new release is, and whether or not the new release has substantially different, either better or worse, reliability than the one currently in production. Customers are demanding quantitative evidence, based on pre-release metrics, to help them decide whether or not to upgrade (and thereby offer new features and capabilities to their customers). Finding ways to estimate future reliability performance is not easy - we have evaluated many prerelease development and test metrics in search of reliability predictors that are sufficiently accurate and also apply to a broad range of software products. This paper describes a successful model that has resulted from these efforts, and also presents both a functional extension and a further conceptual simplification of the extended model that enables us to better communicate key release information to internal stakeholders and customers, without sacrificing predictive accuracy or generalizability. Work remains to be done, but the results of the original model, the extended model, and the simplified version are encouraging and are currently being applied across a range of products and releases. To evaluate whether or not these early predictions are accurate, and also to compare releases that are available to customers, we use a field software reliability assessment mechanism that incorporates two types of customer experience metrics: field bug encounters normalized by usage, and field bug counts, also normalized by usage. Our 'release-overrelease' strategy combines the 'maturity assessment' component (i.e., estimating reliability prior to release to the field) and the 'reliability assessment' component (i.e., gauging actual reliability after release to the field). This overall approach enables us to both predict reliability and compare reliability results for recent releases for a product.

Security has always been concern when it comes to data sharing in cloud computing. Cloud computing provides high computation power and memory. Cloud computing is convenient way for data sharing. But users may sometime needs to outsourced the shared data to cloud server though it contains valuable and sensitive information. Thus it is necessary to provide cryptographically enhanced access control for data sharing system. This paper discuss about the promising access control for data sharing in cloud which is identity-based encryption. We introduce the efficient revocation scheme for the system which is revocable-storage identity-based encryption scheme. It provides both forward and backward security of ciphertext. Then we will have glance at the architecture and steps involved in identity-based encryption. Finally we propose system that provide secure file sharing system using identity-based encryption scheme.

This presents a new model to support empirical failure probability estimation for a software-intensive system. The new element of the approach is that it combines the results of testing using a simulated hardware platform with results from testing on the real platform. This approach addresses a serious practical limitation of a technique known as statistical testing. This limitation will be called the test time expansion problem (or simply the 'time problem'), which is that the amount of testing required to demonstrate useful levels of reliability over a time period T is many orders of magnitude greater than T. The time problem arises whether the aim is to demonstrate ultra-high reliability levels for protection system, or to demonstrate any (desirable) reliability levels for continuous operation ('high demand') systems. Specifically, the theoretical feasibility of a platform simulation approach is considered since, if this is not proven, questions of practical implementation are moot. Subject to the assumptions made in the paper, theoretical feasibility is demonstrated.

This paper focuses on one type of Covert Storage Channel (CSC) that uses the 6-bit TCP flag header in TCP/IP network packets to transmit secret messages between accomplices. We use relative entropy to characterize the irregularity of network flows in comparison to normal traffic. A normal profile is created by the frequency distribution of TCP flags in regular traffic packets. In detection, the TCP flag frequency distribution of network traffic is computed for each unique IP pair. In order to evaluate the accuracy and efficiency of the proposed method, this study uses real regular traffic data sets as well as CSC messages using coding schemes under assumptions of both clear text, composed by a list of keywords common in Unix systems, and encrypted text. Moreover, smart accomplices may use only those TCP flags that are ever appearing in normal traffic. Then, in detection, the relative entropy can reveal the dissimilarity of a different frequency distribution from this normal profile. We have also used different data processing methods in detection: one method summarizes all the packets for a pair of IP addresses into one flow and the other uses a sliding moving window over such a flow to generate multiple frames of packets. The experimentation results, displayed by Receiver Operating Characteristic (ROC) curves, have shown that the method is promising to differentiate normal and CSC traffic packet streams. Furthermore the delay of raising an alert is analyzed for CSC messages to show its efficiency.

Organizations are experiencing an ever-growing concern of how to identify and defend against insider threats. Those who have authorized access to sensitive organizational data are placed in a position of power that could well be abused and could cause significant damage to an organization. This could range from financial theft and intellectual property theft to the destruction of property and business reputation. Traditional intrusion detection systems are neither designed nor capable of identifying those who act maliciously within an organization. In this paper, we describe an automated system that is capable of detecting insider threats within an organization. We define a tree-structure profiling approach that incorporates the details of activities conducted by each user and each job role and then use this to obtain a consistent representation of features that provide a rich description of the user's behavior. Deviation can be assessed based on the amount of variance that each user exhibits across multiple attributes, compared against their peers. We have performed experimentation using ten synthetic data-driven scenarios and found that the system can identify anomalous behavior that may be indicative of a potential threat. We also show how our detection system can be combined with visual analytics tools to support further investigation by an analyst.

The principal mission of Multi-Source Multicast (MSM) is to disseminate all messages from all sources in a network to all destinations. MSM is utilized in numerous applications. In many of them, securing the messages disseminated is critical. A common secure model is to consider a network where there is an eavesdropper which is able to observe a subset of the network links, and seek a code which keeps the eavesdropper ignorant regarding all the messages. While this is solved when all messages are located at a single source, Secure MSM (SMSM) is an open problem, and the rates required are hard to characterize in general. In this paper, we consider Individual Security, which promises that the eavesdropper has zero mutual information with each message individually. We completely characterize the rate region for SMSM under individual security, and show that such a security level is achievable at the full capacity of the network, that is, the cut-set bound is the matching converse, similar to non-secure MSM. Moreover, we show that the field size is similar to non-secure MSM and does not have to be larger due to the security constraint.

Linking the growing IPv6 deployment to existing IPv4 addresses is an interesting field of research, be it for network forensics, structural analysis, or reconnaissance. In this work, we focus on classifying pairs of server IPv6 and IPv4 addresses as siblings, i.e., running on the same machine. Our methodology leverages active measurements of TCP timestamps and other network characteristics, which we measure against a diverse ground truth of 682 hosts. We define and extract a set of features, including estimation of variable (opposed to constant) remote clock skew. On these features, we train a manually crafted algorithm as well as a machine-learned decision tree. By conducting several measurement runs and training in cross-validation rounds, we aim to create models that generalize well and do not overfit our training data. We find both models to exceed 99% precision in train and test performance. We validate scalability by classifying 149k siblings in a large-scale measurement of 371k sibling candidates. We argue that this methodology, thoroughly cross-validated and likely to generalize well, can aid comparative studies of IPv6 and IPv4 behavior in the Internet. Striving for applicability and replicability, we release ready-to-use source code and raw data from our study.

The vision of cyber-physical systems (CPSs) considered the Internet as the future communication network for such systems. A challenge with this regard is to provide high communication reliability, especially, for CPSs applications in critical infrastructures. Examples include smart grid applications with reliability requirements between 99-99.9999% [2]. Even though the Internet is a cost effective solution for such applications, the reliability of its end-to-end (e2e) paths is inadequate (often less than 99%). In this paper, we propose Reliable Multipath Communication Approach for Internet-based CPSs (RC4CPS). RC4CPS is an e2e approach that utilizes the inherent redundancy of the Internet and multipath (MP) transport protocols concept to improve reliability measured in terms of availability. It provides online monitoring and MP selection in order to fulfill the application specific reliability requirement. In addition, our MP selection considers e2e paths dependency and unavailability prediction to maximize the reliability gains of MP communication. Our results show that RC4CPS dynamic MP selection satisfied the reliability requirement along with selecting e2e paths with low dependency and unavailability probability.