The ever-evolving and intricate nature of cyber environments, coupled with the escalating risk of cyber-attacks, necessitates robust solutions in the realm of cybersecurity. Knowledge graphs have emerged as a promising avenue for consolidating, representing, managing, and reasoning over cyber threat intelligence. However, applying knowledge graphs to tackle real-world challenges in cyber-attack and defense scenarios remains an area requiring further exploration. This paper aims to address this gap by providing a comprehensive overview of the fundamental concepts, schema design, and construction methodologies for the cybersecurity knowledge graph. To facilitate future research endeavors, we have carefully curated datasets and open-source libraries tailored for knowledge construction and information extraction tasks. Furthermore, we present a detailed comparative review of recent advancements in the application scenarios of cybersecurity knowledge graphs. To provide clarity and organization, we introduce a novel classification framework that categorizes interconnected works into distinct primary categories and subcategories. The paper concludes by outlining potential research directions in the cybersecurity knowledge graph domain, paving the way for further advancements and innovations in the field.

Organizations strive to secure their valuable data and minimise potential damages, recognising that critical operations are susceptible to attacks. This research paper seeks to elucidate the concept of proactive cyber threat hunting. The proposed framework is to help organisations check their preparedness against upcoming threats and their probable mitigation plan. While traditional threat detection methods have been implemented, they often need to address the evolving landscape of advanced cyber threats. Organisations must adopt proactive threat-hunting strategies to safeguard business operations and identify and mitigate unknown or undetected network threats. This research proposes a conceptual model based on a review of the literature. The proposed framework will help the organisation recover from the attack. As the recovery time is less, the financial loss for the company will also be reduced. Also, the attacker might need more time to gather data, so there will be less stealing of confidential information. Cybersecurity companies use proactive cyber defence strategies to reduce an attacker s time on the network. The different frameworks used are SANS, MITRE, Hunting ELK, Logstash, Digital Kill Chain, Model in Diamonds, and NIST Framework for Cybersecurity, which proposes a proactive approach. It is beneficial for the defensive security team to assess their capabilities to defend against Advanced Threats Persistent (ATP) and a wide range of attack vectors.

Advanced persistent threat (APT) attack is one of the most serious threats to power system cyber security. ATT\&CK framework integrates the known historical and practical APT attack tactics and techniques to form a general language for describing hacker behavior and an abstract knowledge base framework for hacker attacks. Combined with the ATT\&CK for ICS framework, this paper combed the known attack techniques used by viruses or hacker groups aimed at cyberattacks on infrastructure, especially power systems. Then found the corresponding mitigations for each attack technique, and merged them. Next, we listed the high frequency and important mitigations for reference. At last, we proposed a cyber security defense model suitable for ICS to provide a reference for security teams on how to apply ATT\&ck; other similar cyberattack frameworks.

The rapid growth of communication networks, coupled with the increasing complexity of cyber threats, necessitates the implementation of proactive measures to protect networks and systems. In this study, we introduce a federated learning-based approach for cyber threat hunting at the endpoint level. The proposed method utilizes the collective intelligence of multiple devices to effectively and confidentially detect attacks on individual machines. A security assessment tool is also developed to emulate the behavior of adversary groups and Advanced Persistent Threat (APT) actors in the network. This tool provides network security experts with the ability to assess their network environment s resilience and aids in generating authentic data derived from diverse threats for use in subsequent stages of the federated learning (FL) model. The results of the experiments demonstrate that the proposed model effectively detects cyber threats on the devices while safeguarding privacy.

Advanced Persistent Threats (APTs) have been a major challenge in securing both Information Technology (IT) and Operational Technology (OT) systems. APT is a sophisticated attack that masquerade their actions to navigates around defenses, breach networks, often, over multiple network hosts and evades detection. It also uses “low-and-slow” approach over a long period of time. Resource availability, integrity, and confidentiality of the operational cyber-physical systems (CPS) state and control is highly impacted by the safety and security measures in place. A framework multi-stage detection approach termed “APT$_\textrmDASAC$” to detect different tactics, techniques, and procedures (TTPs) used during various APT steps is proposed. Implementation was carried out in three stages: (i) Data input and probing layer - this involves data gathering and pre-processing, (ii) Data analysis layer; applies the core process of “APT$_\textrmDASAC$” to learn the behaviour of attack steps from the sequence data, correlate and link the related output and, (iii) Decision layer; the ensemble probability approach is utilized to integrate the output and make attack prediction. The framework was validated with three different datasets and three case studies. The proposed approach achieved a significant attacks detection capability of 86.36\% with loss as 0.32\%, demonstrating that attack detection techniques applied that performed well in one domain may not yield the same good result in another domain. This suggests that robustness and resilience of operational systems state to withstand attack and maintain system performance are regulated by the safety and security measures in place, which is specific to the system in question.

Advanced Persistent Threats (APTs) have significantly impacted organizations over an extended period with their coordinated and sophisticated cyberattacks. Unlike signature-based tools such as antivirus and firewalls that can detect and block other types of malware, APTs exploit zero-day vulnerabilities to generate new variants of undetectable malware. Additionally, APT adversaries engage in complex relationships and interactions within network entities, necessitating the learning of interactions in network traffic flows, such as hosts, users, or IP addresses, for effective detection. However, traditional deep neural networks often fail to capture the inherent graph structure and overlook crucial contextual information in network traffic flows. To address these issues, this research models APTs as heterogeneous graphs, capturing the diverse features and complex interactions in network flows. Consequently, a hetero-geneous graph transformer (HGT) model is used to accurately distinguish between benign and malicious network connections. Experiment results reveal that the HGT model achieves better performance, with 100 \% accuracy and accelerated learning time, outperferming homogeneous graph neural network models.

Advanced persistent threats (APTs) have novel features such as multi-stage penetration, highly-tailored intention, and evasive tactics. APTs defense requires fusing multi-dimensional Cyber threat intelligence data to identify attack intentions and conducts efficient knowledge discovery strategies by data-driven machine learning to recognize entity relationships. However, data-driven machine learning lacks generalization ability on fresh or unknown samples, reducing the accuracy and practicality of the defense model. Besides, the private deployment of these APT defense models on heterogeneous environments and various network devices requires significant investment in context awareness (such as known attack entities, continuous network states, and current security strategies). In this paper, we propose a few-shot multi-domain knowledge rearming (FMKR) scheme for context-aware defense against APTs. By completing multiple small tasks that are generated from different network domains with meta-learning, the FMKR firstly trains a model with good discrimination and generalization ability for fresh and unknown APT attacks. In each FMKR task, both threat intelligence and local entities are fused into the support/query sets in meta-learning to identify possible attack stages. Secondly, to rearm current security strategies, an finetuning-based deployment mechanism is proposed to transfer learned knowledge into the student model, while minimizing the defense cost. Compared to multiple model replacement strategies, the FMKR provides a faster response to attack behaviors while consuming less scheduling cost. Based on the feedback from multiple real users of the Industrial Internet of Things (IIoT) over 2 months, we demonstrate that the proposed scheme can improve the defense satisfaction rate.

Past Advanced Persistent Threat (APT) attacks on Industrial Internet-of-Things (IIoT), such as the 2016 Ukrainian power grid attack and the 2017 Saudi petrochemical plant attack, have shown the disruptive effects of APT campaigns while new IIoT malware continue to be developed by APT groups. Existing APT detection systems have been designed using cyberattack TTPs modelled for enterprise IT networks and leverage specific data sources (e.g., Linux audit logs, Windows event logs) which are not found on ICS devices. In this work, we propose RAPTOR, a system to detect APT campaigns in IIoT. Using cyberattack TTPs modelled for ICS/OT environments and focusing on ‘invariant’ attack phases, RAPTOR detects and correlates various APT attack stages in IIoT leveraging data which can be readily collected from ICS devices/networks (packet traffic traces, IDS alerts). Subsequently, it constructs a high-level APT campaign graph which can be used by cybersecurity analysts towards attack analysis and mitigation. A performance evaluation of RAPTOR’s APT attack-stage detection modules shows high precision and low false positive/negative rates. We also show that RAPTOR is able to construct the APT campaign graph for APT attacks (modelled after real-world attacks on ICS/OT infrastructure) executed on our IIoT testbed.

With the rapid evolution of the Internet and the prevalence of sophisticated adversarial cyber threats, it has become apparent that an equally rapid development of new Situation Awareness techniques is needed. The vast amount of data produced everyday by Intrusion Detection Systems, Firewalls, Honeypots and other systems can quickly become insurmountable to analyze by the domain experts. To enhance the human - machine interaction, new Visual Analytics systems need to be implemented and tested, bridging the gap between the detection of possible malicious activity, identifying it and taking the necessary measures to stop its propagation. The detection of previously unknown, highly sophisticated Advanced Persistent Threats (APT) adds a higher degree of complexity to this task. In this paper, we discuss the principles inherent to Visual Analytics and propose a new technique for the detection of APT attacks through the use of anomaly and behavior-based analysis. Our ultimate goal is to define sophisticated cyber threats by their defining characteristics and combining those to construct a pattern of behavior, which can be presented in visual form to be explored and analyzed. This can be achieved through the use of our Multi-Agent System for Advanced Persistent Threat Detection (MASFAD) framework and the combination of highly-detailed and dynamic visualization techniques. This paper was originally presented at the NATO Science and Technology Organization Symposium (ICMCIS) organized by the Information Systems Technology (IST) Panel, IST-200 RSY - the ICMCIS, held in Skopje, North Macedonia, 16–17 May 2023.

As cyber attacks grow in complexity and frequency, cyber threat intelligence (CTI) remains a priority objective for defenders. A critical component of CTI at the strategic level of defensive operations is attack attribution. Attributing an attack to a threat group informs defenders on adversaries that are actively engaging them and advances their ability respond. In this paper, we propose a data analytic approach towards threat attribution using adversary playbooks of tactics, techniques, and procedures (TTPs). Specifically, our approach uses association rule mining on a large real world CTI dataset to extend known threat TTP playbooks with statistically probable TTPs the adversary may deploy. The benefits are twofold. First, we offer a dataset of learned TTP associations and extended threat playbooks. Second, we show that we can attribute attacks using a weighted Jaccard similarity with 96\% accuracy.

Advanced Persistent Threat (APT) attacks are complex, employing diverse attack elements and increasingly intelligent techniques. This paper introduces a tool for security risk assessment specifically designed for these attacks. This tool assists security teams in systematically analyzing APT attacks to derive adaptive security requirements for mission-critical target systems. Additionally, the tool facilitates the assessment of security risks, providing a comprehensive understanding of their impact on target systems. By leveraging this tool, security teams can enhance defense strategies, mitigating potential threats and ensuring the security of target systems.

The rapid growth of communication networks, coupled with the increasing complexity of cyber threats, necessitates the implementation of proactive measures to protect networks and systems. In this study, we introduce a federated learning-based approach for cyber threat hunting at the endpoint level. The proposed method utilizes the collective intelligence of multiple devices to effectively and confidentially detect attacks on individual machines. A security assessment tool is also developed to emulate the behavior of adversary groups and Advanced Persistent Threat (APT) actors in the network. This tool provides network security experts with the ability to assess their network environment s resilience and aids in generating authentic data derived from diverse threats for use in subsequent stages of the federated learning (FL) model. The results of the experiments demonstrate that the proposed model effectively detects cyber threats on the devices while safeguarding privacy.

The number of Internet of Things (IoT) devices being deployed into networks is growing at a phenomenal pace, which makes IoT networks more vulnerable in the wireless medium. Advanced Persistent Threat (APT) is malicious to most of the network facilities and the available attack data for training the machine learning-based Intrusion Detection System (IDS) is limited when compared to the normal traffic. Therefore, it is quite challenging to enhance the detection performance in order to mitigate the influence of APT. Therefore, Prior Knowledge Input (PKI) models are proposed and tested using the SCVIC-APT2021 dataset. To obtain prior knowledge, the proposed PKI model pre-classifies the original dataset with unsupervised clustering method. Then, the obtained prior knowledge is incorporated into the supervised model to decrease training complexity and assist the supervised model in determining the optimal mapping between the raw data and true labels. The experimental findings indicate that the PKI model outperforms the supervised baseline, with the best macro average F1-score of 81.37\%, which is 10.47\% higher than the baseline.

The last decade witnessed a gradual shift from cloudbased computing towards ubiquitous computing, which has put at a greater security risk every element of the computing ecosystem including devices, data, network, and decision making. Indeed, emerging pervasive computing paradigms have introduced an uncharted territory of security vulnerabilities and a wider attack surface, mainly due to network openness, the underlying mechanics that enable intelligent functions, and the deeply integrated physical and cyber spaces. Furthermore, interconnected computing environments now enjoy many unconventional characteristics that mandate a radical change in security engineering tools. This need is further exacerbated by the rapid emergence of new Advanced Persistent Threats (APTs) that target critical infrastructures and aim to stealthily undermine their operations in innovative and intelligent ways. To enable system and network designers to be prepared to face this new wave of dangerous threats, this paper overviews recent APTs in emerging computing systems and proposes a new approach to APTs that is more tailored towards such systems compared to traditional IT infrastructures. The proposed APT lifecycle will inform security decisions and implementation choices in future pervasive networked systems.

Currently, there are no mission-capable systems that can successfully detect advanced persistent threats (APTs). These types of threats are hazardous in critical infrastructures (CIs). Due to the integration of operational technology (OT) and information communication technology (ICT), CI systems are particularly vulnerable to cyberattacks. In addition, power systems, in particular, are an attractive target for attackers, as they are responsible for the operation of modern infrastructures and are thus of great importance for modern warfare or even for strategic purposes of other criminal activities. Virtual power plants (VPPs) are a new implementation of power plants for energy management. The protection of virtual power plants against APTs is not yet sufficiently researched. This circumstance raises the research question - What might an APT detection system architecture for VPPs look like? Our methodology is based on intensive literature research to bundle knowledge from different sub-areas to solve a superordinate problem. After the literature review and domain analysis, a synthesis of new knowledge is provided in the presentation of a possible architecture. The in-depth proposal for a potential system architecture relies on the study of VPPs, APTs, and previous prevention mechanisms. The architecture is then evaluated for its effectiveness based on the challenges identified.

Traditional defense methods can only evaluate a single security element and cannot determine the threat of Advanced Persistent Threat (APT) according to multi-source data. This paper proposes a network security situation awareness (NSSA) model to get the network situation under APT attacks based on knowledge graph. Firstly, the vulnerability knowledge graph and APT attack knowledge graph are constructed using public security databases and ATT\&CK (Adversarial Tactics, Techniques, and Common Knowledge), and the targeted knowledge graph APT-NSKG is obtained by combining the two using Bidirectional Encoder Representations from Transformers (BERT). Then, according to the Endsley model and the characteristics of APT , the NSSA model for APT is proposed. The model uses APTNSKG to obtain situation elements, and then comprehensively assesses and predicts the network situation from the perspectives of network asset dimension, vulnerability dimension, security dimension and threat dimension. Finally, the effectiveness of the model is verified by the data from the U.S. Cybersecurity and Infrastructure Security Agency.

The paper focus on the application of Systems Dynamics Modelling (SDM) for simulating socio-technical vulnerabilities of Advanced Persistent Threats (APT) to unravel Human Computer Interaction (HCI) for strategic visibility of threat actors. SDM has been widely applied to analyze nonlinear, complex, and dynamic systems in social sciences and technology. However, its application in the cyber security domain especially APT that involve complex and dynamic human computer interaction is a promising but scant research domain. While HCI deals with the interaction between one or more humans and between one or more computers for greater usability, this same interactive process is exploited by the APT actor. In this respect, using a data breach case study, we applied the socio-technical vulnerabilities classification as a theoretical lens to model socio and technical vulnerabilities on systems dynamics using Vensim software. The variables leading to the breach were identified, entered into Vensim software, and simulated to get the results. The results demonstrated an optimal interactive mix of one or more of the six socio variables and three technical variables leading to the data breach. SDM approach thus provides insights into the dynamics of the threat as well as throw light on the strategies to undertake for minimizing APT risks. This can assist in the reduction of the attack surface and reinforce mitigation efforts (prior to exfiltration) should an APT attack occur. In this paper, we thus propose and validate the application of system dynamics approach for designing a dynamic threat assessment framework for socio-technical vulnerabilities of APT.

Advanced persistent threat (APT) attacks have caused severe damage to many core information infrastructures. To tackle this issue, the graph-based methods have been proposed due to their ability for learning complex interaction patterns of network entities with discrete graph snapshots. However, such methods are challenged by the computer networking model characterized by a natural continuous-time dynamic heterogeneous graph. In this paper, we propose a heterogeneous graph neural network based APT detection method in smart grid clouds. Our model is an encoderdecoder structure. The encoder uses heterogeneous temporal memory and attention embedding modules to capture contextual information of interactions of network entities from the time and spatial dimensions respectively. We implement a prototype and conduct extensive experiments on real-world cyber-security datasets with more than 10 million records. Experimental results show that our method can achieve superior detection performance than state-of-the-art methods.

With the proliferation of Low Earth Orbit (LEO) spacecraft constellations, comes the rise of space-based wireless cognitive communications systems (CCS) and the need to safeguard and protect data against potential hostiles to maintain widespread communications for enabling science, military and commercial services. For example, known adversaries are using advanced persistent threats (APT) or highly progressive intrusion mechanisms to target high priority wireless space communication systems. Specialized threats continue to evolve with the advent of machine learning and artificial intelligence, where computer systems inherently can identify system vulnerabilities expeditiously over naive human threat actors due to increased processing resources and unbiased pattern recognition. This paper presents a disruptive abuse case for an APT-attack on such a CCS and describes a trade-off analysis that was performed to evaluate a variety of machine learning techniques that could aid in the rapid detection and mitigation of an APT-attack. The trade results indicate that with the employment of neural networks, the CCS s resiliency would increase its operational functionality, and therefore, on-demand communication services reliability would increase. Further, modelling, simulation, and analysis (MS\&A) was achieved using the Knowledge Discovery and Data Mining (KDD) Cup 1999 data set as a means to validate a subset of the trade study results against Training Time and Number of Parameters selection criteria. Training and cross-validation learning curves were computed to model the learning performance over time to yield a reasonable conclusion about the application of neural networks.

Counteracting the most dangerous attacks –advanced persistent threats – is an actual problem of modern enterprises. Usually these threats aimed not only at information resources but also at software and hardware resources of automated systems of industrial plants. As a rule, attackers use a number of methods including social engineering methods. The article is devoted to development of the methods for timely prevention from advanced persistent threats based on analysis of attackers’ tactics. Special attention in the article is paid to methods for detection provocations of the modernization of protection systems, as well as methods for monitoring the state of resources of the main automated system. Technique of identification of suspicious changes in the resources is also considered in the article. The result of applying this set of methods will help to increase the protection level of automated systems’ resources.

Data management systems in smart grids have to address advanced persistent threats (APTs), where malware injection methods are performed by the attacker to launch stealthy attacks and thus steal more data for illegal advantages. In this paper, we present a hierarchical deep reinforcement learning based APT detection scheme for smart grids, which enables the control center of the data management system to choose the APT detection policy to reduce the detection delay and improve the data protection level without knowing the attack model. Based on the state that consists of the size of the gathered power usage data, the priority level of the data, and the detection history, this scheme develops a two-level hierarchical structure to compress the high-dimensional action space and designs four deep dueling networks to accelerate the optimization speed with less over-estimation. Detection performance bound is provided and simulation results show that the proposed scheme improves both the data protection level and the utility of the control center with less detection delay.

To meet the high safety and reliability requirements of today’s power transformers, advanced online diagnosis systems using seamless communications and information technologies have been developed, which potentially presents growing cybersecurity concerns. This paper provides practical attack models breaching a power transformer diagnosis system (PTDS) in a digital substation by advanced persistent threats (APTs) and proposes a security testbed for developing future security built-in PTDS against APTs. The proposed security testbed includes: 1) a real-time substation power system simulator, 2) a real-time cyber system, and 3) penetration testing tools. Several real cyber-attacks are generated and the impact on a digital substation are provided to validate the feasibility of the proposed security testbed. The proposed PTDS-focused security testbed will be used to develop self-safe defense strategies against malicious cyber-attacks in a digital substation environment.

Neural Network Resiliency - With the proliferation of Low Earth Orbit (LEO) spacecraft constellations, comes the rise of space-based wireless cognitive communications systems (CCS) and the need to safeguard and protect data against potential hostiles to maintain widespread communications for enabling science, military and commercial services. For example, known adversaries are using advanced persistent threats (APT) or highly progressive intrusion mechanisms to target high priority wireless space communication systems. Specialized threats continue to evolve with the advent of machine learning and artificial intelligence, where computer systems inherently can identify system vulnerabilities expeditiously over naive human threat actors due to increased processing resources and unbiased pattern recognition. This paper presents a disruptive abuse case for an APT-attack on such a CCS and describes a trade-off analysis that was performed to evaluate a variety of machine learning techniques that could aid in the rapid detection and mitigation of an APT-attack. The trade results indicate that with the employment of neural networks, the CCS s resiliency would increase its operational functionality, and therefore, on-demand communication services reliability would increase. Further, modelling, simulation, and analysis (MS\&A) was achieved using the Knowledge Discovery and Data Mining (KDD) Cup 1999 data set as a means to validate a subset of the trade study results against Training Time and Number of Parameters selection criteria. Training and cross-validation learning curves were computed to model the learning performance over time to yield a reasonable conclusion about the application of neural networks.

Cybersecurity attacks, which have many business impacts, continuously become more intelligent and complex. These attacks take the form of a combination of various attack elements. APT attacks reflect this characteristic well. To defend against APT attacks, organizations should sufficiently understand these attacks based on the attack elements and their relations and actively defend against these attacks in multiple dimensions. Most organizations perform risk management to manage their information security. Generally, they use the information system risk assessment (ISRA). However, the method has difficulties supporting sufficiently analyzing security risks and actively responding to these attacks due to the limitations of asset-driven qualitative evaluation activities. In this paper, we propose a threat-driven risk assessment method. This method can evaluate how dangerous APT attacks are for an organization, analyze security risks from multiple perspectives, and support establishing an adaptive security strategy.

Operating systems are essential software components for any computer. The goal of computer system manu-facturers is to provide a safe operating system that can resist a range of assaults. APTs (Advanced Persistent Threats) are merely one kind of attack used by hackers to penetrate organisations (APT). Here, we will apply the MITRE ATT&CK approach to analyze the security of Windows and Linux. Using the results of a series of vulnerability tests conducted on Windows 7, 8, 10, and Windows Server 2012, as well as Linux 16.04, 18.04, and its most current version, we can establish which operating system offers the most protection against future assaults. In addition, we have shown adversarial reflection in response to threats. We used ATT &CK framework tools to launch attacks on both platforms.