Biblio

With the rapid development of radio detection and wireless communication, narrowband radio-frequency interference (NB-RFI) is a serious threat for GNSS-R (global navigation satellite systems - reflectometry) receivers. However, interferometric GNSS-R (iGNSS-R) is more prone to the NB-RFIs than conventional GNSS-R (cGNSS-R), due to wider bandwidth and unclean replica. Therefore, there is strong demand of detecting and mitigating NB-RFIs for GNSS-R receivers, especially iGNSS-R receivers. Hence, focusing on working with high sampling rate and simplifying the fixed-point implementation on FPGA, this paper proposes a system design exploiting cascading IIR band-stop filters (BSFs) to suppress NB-RFIs. Furthermore, IIR BSF compared with IIR notch filter (NF) and IIR band-pass filter (BPF) is the merely choice that is able to mitigate both white narrowband interference (WNBI) and continuous wave interference (CWI) well. Finally, validation and evaluation are conducted, and then it is indicated that the system design can detect NB-RFIs and suppress WNBI and CWI effectively, which improves the signal-to-noise ratio (SNR) of the Delay-Doppler map (DDM).

Nowadays, everyone is living in a digital world with various of virtual experiences and realities, but all of them may eventually cause real threats in our real world. Some of these threats have been born together with the first electronic mail service. Some of them might be considered as really basic and simple, compared to others that were developed and advanced in time to adapt themselves for the security defense mechanisms of the modern digital world. On a daily basis, more than 238.4 billion emails are sent worldwide, which makes more than 2.7 million emails per second, and these statistics are only from the publicly visible networks. Having that information and considering around 60% and above of all emails as threatening or not legitimate, is more than concerning. Unfortunately, even the modern security measures and systems are not capable to identify and prevent all the fraudulent content that is created and distributed every day. In this paper we will cover the most common attack vectors, involving the already mass email infrastructures, the required contra measures to minimize the impact over the corporate environments and what else should be developed to mitigate the modern sophisticated email attacks.

With the rapidly increasing connectivity in cyberspace, Insider Threat is becoming a huge concern. Insider threat detection from system logs poses a tremendous challenge for human analysts. Analyzing log files of an organization is a key component of an insider threat detection and mitigation program. Emerging machine learning approaches show tremendous potential for performing complex and challenging data analysis tasks that would benefit the next generation of insider threat detection systems. However, with huge sets of heterogeneous data to analyze, applying machine learning techniques effectively and efficiently to such a complex problem is not straightforward. In this paper, we extract a concise set of features from the system logs while trying to prevent loss of meaningful information and providing accurate and actionable intelligence. We investigate two unsupervised anomaly detection algorithms for insider threat detection and draw a comparison between different structures of the system logs including daily dataset and periodically aggregated one. We use the generated anomaly score from the previous cycle as the trust score of each user fed to the next period's model and show its importance and impact in detecting insiders. Furthermore, we consider the psychometric score of users in our model and check its effectiveness in predicting insiders. As far as we know, our model is the first one to take the psychometric score of users into consideration for insider threat detection. Finally, we evaluate our proposed approach on CERT insider threat dataset (v4.2) and show how it outperforms previous approaches.

DDoS attacks are a significant threat to internet service or infrastructure providers. This poster presents an FPGA-accelerated device and DDoS mitigation technique to overcome such attacks. Our work addresses amplification attacks whose goal is to generate enough traffic to saturate the victims links. The main idea of the device is to efficiently filter malicious traffic at high-speeds directly in the backbone infrastructure before it even reaches the victim's network. We implemented our solution for two FPGA platforms using the high-level description in P4, and we report on its performance in terms of throughput and hardware resources.

This paper proposes a framework for predicting and mitigating insider collusion threat in relational database systems. The proposed model provides a robust technique for database architect and administrators to predict insider collusion threat when designing database schema or when granting privileges. Moreover, it proposes a real time monitoring technique that monitors the growing knowledgebases of insiders while executing transactions and the possible collusion insider attacks that may be launched based on insiders accesses and inferences. Furthermore, the paper proposes a mitigating technique based on the segregation of duties principle and the discovered collusion insider threat to mitigate the problem. The proposed model was tested to show its usefulness and applicability.

Distributed Denial of Service (DDoS) attacks remain one of the top threats to enterprise networks and ISPs nowadays. It can cause tremendous damage by bringing down online websites or services. Existing DDoS defense solutions either brings high cost such as upgrading existing firewall or IPS, or bring excessive traffic delay by using third-party cloud-based DDoS filtering services. In this work, we propose a DDoS defense framework that utilizes Network Function Virtualization (NFV) architecture to provide low cost and highly flexible solutions for enterprises. In particular, the system uses virtual network agents to perform attack traffic filtering before they are forwarded to the target server. Agents are created on demand to verify the authenticity of the source of packets, and drop spoofed packets in order protect the target server. Furthermore, we design a scalable and flexible dispatcher to forward packets to corresponding agents for processing. A bucket-based forwarding mechanism is used to improve the scalability of the dispatcher through batching forwarding. The dispatcher can also adapt to agent addition and removal. Our simulation results demonstrate that the dispatcher can effectively serve a large volume of traffic with low dropping rate. The system can successfully mitigate SYN flood attack by introducing minimal performance degradation to legitimate traffic.

The dynamically changing landscape of DDoS threats increases the demand for advanced security solutions. The rise of massive IoT botnets enables attackers to mount high-intensity short-duration ”volatile ephemeral” attack waves in quick succession. Therefore the standard human-in-the-loop security center paradigm is becoming obsolete. To battle the new breed of volatile DDoS threats, the intrusion detection system (IDS) needs to improve markedly, at least in reaction times and in automated response (mitigation). Designing such an IDS is a daunting task as network operators are traditionally reluctant to act - at any speed - on potentially false alarms. The primary challenge of a low reaction time detection system is maintaining a consistently low false alarm rate. This paper aims to show how a practical FPGA-based DDoS detection and mitigation system can successfully address this. Besides verifying the model and algorithms with real traffic ”in the wild”, we validate the low false alarm ratio. Accordingly, we describe a methodology for determining the false alarm ratio for each involved threat type, then we categorize the causes of false detection, and provide our measurement results. As shown here, our methods can effectively mitigate the volatile ephemeral DDoS attacks, and accordingly are usable both in human out-of-loop and on-the-loop next-generation security solutions.

The technological development of automated vehicles opens novel cybersecurity threats and risks for road safety. Increased connectivity often results in increased risks of a cyber-security attacks, which is one of the biggest challenges for the automotive industry that undergoes a profound transformation. State of the art studies evaluated potential attacks and recommended possible measures, from technical and organizational perspective to face these challenges. In this position paper, we review these techniques and methods and show that some of the different solutions complement each other while others overlap or are even incompatible or contradictory. Based on this gap analysis, we advocate for the need of a comprehensive framework that integrates technical and organizational mitigation measures to enhance the cybersecurity of automotive vehicles.

Compromising IoT devices to build botnets and disrupt critical infrastructure is an existential threat. Refrigerators, washing machines, DVRs, security cameras, and other consumer goods are high value targets for attackers due to inherent security weaknesses, a lack of consumer security awareness, and an absence of market forces or regulatory requirements to motivate IoT security. As a result of the deficiencies, attackers have quickly assembled large scale botnets of IoT devices to disable Internet infrastructure and deny access to dominant web properties with near impunity. IoT malware is often transmitted from host to host similar to how biological viruses spread in populations. Both biological viruses and computer malware may exhibit epidemic characteristics when spreading in populations of vulnerable hosts. Vaccines are used to stimulate resistance to biological viruses by inoculating a sufficient number of hosts in the vulnerable population to limit the spread of the biological virus and prevent epidemics. Inoculation programs may be viewed as a human instigated epidemic that spreads a vaccine in order to mitigate the damage from a biological virus. In this paper we propose a technique to create an inoculation epidemic for IoT devices using a novel variation of a SIS epidemic model and show experimental results that indicate utility of the approach.

The Internet of Things (IoT) can be described as the ever-growing global network of objects with built-in sensing and communication interfaces such as sensors, Global Positioning devices (GPS) and Local Area Network (LAN) interfaces. Security is by far one of the biggest challenges in IoT networks. This includes secure routing which involves the secure creation of traffic routes and secure transmission of routed packets from a source to a destination. The Routing Protocol for Low-power and Lossy network (RPL) is one of the popular IoT's routing protocol that supports IPv6 communication. However, it suffers from having a basic system for supporting secure routing procedure which makes the RPL vulnerable to many attacks. This includes rank attack manipulation. Objective Function (OF) is one of the extreme importance features of RPL which influences an IoT network in terms of routing strategies as well as network topology. However, current literature lacks study of vulnerability analysis of OFs. Therefore, this paper aims to investigate the vulnerability assessment of OF of RPL protocol. For this, we focus on the rank attack manipulation and two popular OFs: Objective Function Zero (OF0) and the Minimum Rank with Hysteresis Objective Function (MRHOF).

Creating secure and privacy-protecting systems entails the simultaneous coordination of development activities along three different yet mutually influencing dimensions: translating (security and privacy) goals to design choices, analyzing the design for threats, and performing a risk analysis of these threats in light of the goals. These activities are often executed in isolation, and such a disconnect impedes the prioritization of elicited threats, assessment which threats are sufficiently mitigated, and decision-making in terms of which risks can be accepted. In the proposed TMaRA approach, we facilitate the simultaneous consideration of these dimensions by integrating support for threat modeling, risk analysis, and design decisions. Key risk assessment inputs are systematically modeled and threat modeling efforts are fed back into the risk management process. This enables prioritizing threats based on their estimated risk, thereby providing decision support in the mitigation, acceptance, or transferral of risk for the system under design.

Cyber threat hunting is the process of proactively and iteratively formulating and validating threat hypotheses based on security-relevant observations and domain knowledge. To facilitate threat hunting tasks, this paper introduces threat intelligence computing as a new methodology that models threat discovery as a graph computation problem. It enables efficient programming for solving threat discovery problems, equipping threat hunters with a suite of potent new tools for agile codifications of threat hypotheses, automated evidence mining, and interactive data inspection capabilities. A concrete realization of a threat intelligence computing platform is presented through the design and implementation of a domain-specific graph language with interactive visualization support and a distributed graph database. The platform was evaluated in a two-week DARPA competition for threat detection on a test bed comprising a wide variety of systems monitored in real time. During this period, sub-billion records were produced, streamed, and analyzed, dozens of threat hunting tasks were dynamically planned and programmed, and attack campaigns with diverse malicious intent were discovered. The platform exhibited strong detection and analytics capabilities coupled with high efficiency, resulting in a leadership position in the competition. Additional evaluations on comprehensive policy reasoning are outlined to demonstrate the versatility of the platform and the expressiveness of the language.

Shared Threat Intelligence is often imperfect. Especially so called Indicator of Compromise might not be well constructed. This might either be the case if the threat only appeared recently and recordings do not allow for construction of high quality Indicators or the threat is only observed by sharing partners lesser capable to model the threat. However, intrusion detection based on imperfect intelligence yields low quality results. Within this paper we illustrate how one is able to overcome these shortcomings in data quality and is able to achieve solid intrusion detection. This is done by assigning individual weights to observables listed in a STIX™ report to express their significance for detection. For evaluation, an automatized toolchain was developed to mimic the Threat Intelligence sharing ecosystem from initial detection over reporting, sharing, and determining compromise by STIX™-formated data. Multiple strategies to detect and attribute a specific threat are compared using this data, leading up to an approach yielding a F1-Score of 0.79.

A number of online services nowadays rely upon machine learning to extract valuable information from data collected in the wild. This exposes learning algorithms to the threat of data poisoning, i.e., a coordinate attack in which a fraction of the training data is controlled by the attacker and manipulated to subvert the learning process. To date, these attacks have been devised only against a limited class of binary learning algorithms, due to the inherent complexity of the gradient-based procedure used to optimize the poisoning points (a.k.a. adversarial training examples). In this work, we first extend the definition of poisoning attacks to multiclass problems. We then propose a novel poisoning algorithm based on the idea of back-gradient optimization, i.e., to compute the gradient of interest through automatic differentiation, while also reversing the learning procedure to drastically reduce the attack complexity. Compared to current poisoning strategies, our approach is able to target a wider class of learning algorithms, trained with gradient-based procedures, including neural networks and deep learning architectures. We empirically evaluate its effectiveness on several application examples, including spam filtering, malware detection, and handwritten digit recognition. We finally show that, similarly to adversarial test examples, adversarial training examples can also be transferred across different learning algorithms.

With smart phones being indispensable in people's everyday life, Android malware has posed serious threats to their security, making its detection of utmost concern. To protect legitimate users from the evolving Android malware attacks, machine learning-based systems have been successfully deployed and offer unparalleled flexibility in automatic Android malware detection. In these systems, based on different feature representations, various kinds of classifiers are constructed to detect Android malware. Unfortunately, as classifiers become more widely deployed, the incentive for defeating them increases. In this paper, we explore the security of machine learning in Android malware detection on the basis of a learning-based classifier with the input of a set of features extracted from the Android applications (apps). We consider different importances of the features associated with their contributions to the classification problem as well as their manipulation costs, and present a novel feature selection method (named SecCLS) to make the classifier harder to be evaded. To improve the system security while not compromising the detection accuracy, we further propose an ensemble learning approach (named SecENS) by aggregating the individual classifiers that are constructed using our proposed feature selection method SecCLS. Accordingly, we develop a system called SecureDroid which integrates our proposed methods (i.e., SecCLS and SecENS) to enhance security of machine learning-based Android malware detection. Comprehensive experiments on the real sample collections from Comodo Cloud Security Center are conducted to validate the effectiveness of SecureDroid against adversarial Android malware attacks by comparisons with other alternative defense methods. Our proposed secure-learning paradigm can also be readily applied to other malware detection tasks.

Data deduplication [3] is able to effectively identify and eliminate redundant data and only maintain a single copy of files and chunks. Hence, it is widely used in cloud storage systems to save the users' network bandwidth for uploading data. However, the occurrence of deduplication can be easily identified by monitoring and analyzing network traffic, which leads to the risk of user privacy leakage. The attacker can carry out a very dangerous side channel attack, i.e., learn-the-remaining-information (LRI) attack, to reveal users' privacy information by exploiting the side channel of network traffic in deduplication [1]. In the LRI attack, the attacker knows a large part of the target file in the cloud and tries to learn the remaining unknown parts via uploading all possible versions of the file's content. For example, the attacker knows all the contents of the target file X except the sensitive information \texttheta. To learn the sensitive information, the attacker needs to upload m files with all possible values of \texttheta, respectively. If a file Xd with the value \textthetad is deduplicated and other files are not, the attacker knows that the information \texttheta = \textthetad. In the threat model of the LRI attack, we consider a general cloud storage service model that includes two entities, i.e., the user and cloud storage server. The attack is launched by the users who aim to steal the privacy information of other users [1]. The attacker can act as a user via its own account or use multiple accounts to disguise as multiple users. The cloud storage server communicates with the users through Internet. The connections from the clients to the cloud storage server are encrypted by SSL or TLS protocol. Hence, the attacker can monitor and measure the amount of network traffic between the client and server but cannot intercept and analyze the contents of the transmitted data due to the encryption. The attacker can then perform the sophisticated traffic analysis with sufficient computing resources. We propose a simple yet effective scheme, called randomized redundant chunk scheme (RRCS), to significantly mitigate the risk of the LRI attack while maintaining the high bandwidth efficiency of deduplication. The basic idea behind RRCS is to add randomized redundant chunks to mix up the real deduplication states of files used for the LRI attack, which effectively obfuscates the view of the attacker, who attempts to exploit the side channel of network traffic for the LRI attack. RRCS includes three key function modules, range generation (RG), secure bounds setting (SBS), and security-irrelevant redundancy elimination (SRE). When uploading the random-number redundant chunks, RRCS first uses RG to generate a fixed range [0,$łambda$N] ($łambda$ $ε$ (0,1]), in which the number of added redundant chunks is randomly chosen, where N is the total number of chunks in a file and $łambda$ is a system parameter. However, the fixed range may cause a security issue. SBS is used to deal with the bounds of the fixed range to avoid the security issue. There may exist security-irrelevant redundant chunks in RRCS. SRE reduces the security-irrelevant redundant chunks to improve the deduplication efficiency. The design details are presented in our technical report [5]. Our security analysis demonstrates RRCS can significantly reduce the risk of the LRI attack [5]. We examine the performance of RRCS using three real-world trace-based datasets, i.e., Fslhomes [2], MacOS [2], and Onefull [4], and compare RRCS with the randomized threshold scheme (RTS) [1]. Our experimental results show that source-based deduplication eliminates 100% data redundancy which however has no security guarantee. File-level (chunk-level) RTS only eliminates 8.1% – 16.8% (9.8% – 20.3%) redundancy, due to only eliminating the redundancy of the files (chunks) that have many copies. RRCS with $łambda$ = 0.5 eliminates 76.1% – 78.0% redundancy and RRCS with $łambda$ = 1 eliminates 47.9% – 53.6% redundancy.

Embedded systems are prone to security attacks from their limited resources available for self-protection and unsafe language typically used for application programming. Attacks targeting control flow is one of the most common exploitations for embedded systems. We propose a hardware-level, effective, and low overhead countermeasure to mitigate these types of attacks. In the proposed method, a Built-in Secure Register Bank (BSRB) is introduced to the processor micro-architecture to store the return addresses of subroutines. The inconsistency on the return addresses will direct the processor to select a clean copy to resume the normal control flow and mitigate the security threat. This proposed countermeasure is inaccessible for the programmer and does not require any compiler support, thus achieving better flexibility than software-based countermeasures. Experimental results show that the proposed method only increases the area and power by 3.8% and 4.4%, respectively, over the baseline OpenRISC processor.

Vehicular Ad-Hoc Network (VANET) is a form of Peer-to-Peer (P2P) wireless communication between vehicles, which is characterized by the high mobility. In practice, VANET can be utilized to cater connections via multi-hop communication between vehicles to provide traffic information seamlessly, such as traffic jam and traffic accident, without the need of dedicated centralized infrastructure. Although dedicated infrastructures may also be involved in VANET, such as Road Side Units (RSUs), most of the time VANET relies solely on Vehicle-to-Vehicle (V2V) communication, which makes it vulnerable to several potential attacks in P2P based communication, as there are no trusted authorities that provide authentication and security. One of the potential threats is a Sybil attack, wherein an adversary uses a considerable number of forged identities to illegitimately infuse false or biased information which may mislead a system into making decisions benefiting the adversary. Avoiding Sybil attacks in VANET is a difficult problem, as there are typically no trusted authorities that provide cryptographic assurance of Sybil resilience. This paper presents a technique to detect and mitigate Sybil attacks, which requires no dedicated infrastructure, by utilizing just V2V communication. The proposed method work based on underlying assumption that says the mobility of vehicles in high vehicle density and the limited transmission power of the adversary creates unique groups of vehicle neighbors at a certain time point, which can be calculated in a statistical fashion providing a temporal and spatial analysis to verify real and impersonated vehicle identities. The proposed method also covers the mitigation procedures to create a trust model and announce neighboring vehicles regarding the detected tempered identities in a secure way utilizing Diffie-Hellman key distribution. This paper also presents discussions concerning the proposed approach with regard to benefits and drawbacks of sparse road condition and other potential threats.

Distributed Denial of Service (DDoS) attacks on web applications have been a persistent threat. Existing approaches for mitigating application layer DDoS attacks have limitations such low detection rate and inability to detect attacks targeting resource files. In this work, we propose Application layer DDoS (App-DDoS) attack detection framework by leveraging the concepts of Term Frequency (TF)-Inverse Document Frequency (IDF) and Latent Semantic Indexing (LSI). The approach involves analyzing web server logs to identify popular pages using TF-IDF; building normal resource access profile; generating query of accessed resources; and applying LSI technique to determine the similarity between a given session and known good sessions. A high-level of dissimilarity triggers a DDoS attack warning. We apply the proposed approach to traffics generated from three PHP applications. The initial results suggest that the proposed approach can identify ongoing DDoS attacks against web applications.

Though the telecommunication protocol ARP provides the most prominent service for data transmission in the network by providing the physical layer address for any host's network layer address, its stateless nature remains one of the most well-known opportunities for the attacker community and ultimate threat for the hosts in the network. ARP cache poisoning results in numerous attacks, of which the most noteworthy ones MITM, host impersonation and DoS attacks. This paper presents various recent mitigation methods and proposes a novel mitigation system for ARP cache Poisoning Attacks. The proposed system works as follows: for any ARP Request or Reply messages a time stamp is generated. When it is received or sent by a host, the host will make cross layer inspection and IP-MAC pair matching with ARP table Entry. If ARP table entry matches and cross layer consistency is ensured then ARP reply with Time Stamp is sent. If in both the cases evaluated to be bogus packet, then the IP-MAC pair is added to the untrusted list and further packet inspection is done to ensure no attack has been deployed onto the network. The time is also noted for each entry made into the ARP table which makes ARP stateful. The system is evaluated based on criteria specified by the researchers.

In the context of the emerging Internet of Things (IoT), a proliferation of wireless connectivity can be expected. That ubiquitous wireless communication will be hard to centrally manage and control, and can be expected to be opaque to end users. As a result, owners and users of physical space are threatened to lose control over their digital environments. In this work, we propose the idea of an IoTScanner. The IoTScanner integrates a range of radios to allow local reconnaissance of existing wireless infrastructure and participating nodes. It enumerates such devices, identifies connection patterns, and provides valuable insights for technical support and home users alike. Using our IoTScanner, we investigate metrics that could be used to classify devices and identify privacy threats in an IoT neighborhood.

A Distributed Denial of Service (DDoS) attack is an attempt to make an online service, a network, or even an entire organization, unavailable by saturating it with traffic from multiple sources. DDoS attacks are among the most common and most devastating threats that network defenders have to watch out for. DDoS attacks are becoming bigger, more frequent, and more sophisticated. Volumetric attacks are the most common types of DDoS attacks. A DDoS attack is considered volumetric, or high-rate, when within a short period of time it generates a large amount of packets or a high volume of traffic. High-rate attacks are well-known and have received much attention in the past decade; however, despite several detection and mitigation strategies have been designed and implemented, high-rate attacks are still halting the normal operation of information technology infrastructures across the Internet when the protection mechanisms are not able to cope with the aggregated capacity that the perpetrators have put together. With this in mind, the present paper aims to propose and test a distributed and collaborative architecture for online high-rate DDoS attack detection and mitigation based on an in-memory distributed graph data structure and unsupervised machine learning algorithms that leverage real-time streaming data and analytics. We have successfully tested our proposed mechanism using a real-world DDoS attack dataset at its original rate in pursuance of reproducing the conditions of an actual large scale attack.

In this demo, we address the problem of detecting anomalies on the Internet backbone in near real-time. Many of today's incidents may only become visible from inspecting multiple data sources and by considering multiple vantage points simultaneously. We present a setup based on the distributed forensic platform VAST that was extended to import various data streams from passive measurements and incident reporting at multiple locations, and perform an effective correlation analysis shortly after the data becomes exposed to our queries.

Understanding and fending off attack campaigns against organizations, companies and individuals, has become a global struggle. As today's threat actors become more determined and organized, isolated efforts to detect and reveal threats are no longer effective. Although challenging, this situation can be significantly changed if information about security incidents is collected, shared and analyzed across organizations. To this end, different exchange data formats such as STIX, CyBOX, or IODEF have been recently proposed and numerous CERTs are adopting these threat intelligence standards to share tactical and technical threat insights. However, managing, analyzing and correlating the vast amount of data available from different sources to identify relevant attack patterns still remains an open problem. In this paper we present Mantis, a platform for threat intelligence that enables the unified analysis of different standards and the correlation of threat data trough a novel type-agnostic similarity algorithm based on attributed graphs. Its unified representation allows the security analyst to discover similar and related threats by linking patterns shared between seemingly unrelated attack campaigns through queries of different complexity. We evaluate the performance of Mantis as an information retrieval system for threat intelligence in different experiments. In an evaluation with over 14,000 CyBOX objects, the platform enables retrieving relevant threat reports with a mean average precision of 80%, given only a single object from an incident, such as a file or an HTTP request. We further illustrate the performance of this analysis in two case studies with the attack campaigns Stuxnet and Regin.

The insider threat has been subject of extensive study and many approaches from technical perspective to behavioral perspective and psychological perspective have been proposed to detect or mitigate it. However, it still remains one of the most difficult security issues to combat. In this paper, we propose an ongoing effort on developing a systematic framework to address insider threat challenges by laying a scientific foundation for defensive deception,leveraging moving target defense (MTD), an emerging technique for providing proactive security measurements, and integrating deception and MTD into attribute-based access control (ABAC).