• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.1021-1030
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• 2021

This paper proposes S-CAFG(Stage-based Cyber Attack Flow Graph), a model for effectively describing training scenarios that simulate modern complex cyber attacks. On top of existing graph and tree models, we add a stage node to model more complex scenarios. In order to evaluate the proposed model, we create a complicated scenario and compare how the previous models and S-CAFG express the scenario. As a result, we confirm that S-CAFG can effectively describe various attack scenarios such as simultaneous attacks, additional attacks, and bypass path selection.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.65-72
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• 2020

With the development of information technology and the growth of the scale of system and network, cyber threats and crimes continue to increase. To cope with these threats, cybersecurity training based on actual attacks and defenses is required. However, cybersecurity training requires expert analysis and attack performance, which is inefficient in terms of cost and time. In this paper, we propose a cyber attack simulator that automatically executes attack techniques. This simulator generates attack scenarios by combining attack techniques modeled to be implemented and executes the attack by sequentially executing the derived scenarios. In order to verify the effectiveness of the proposed attack simulator, we experimented by setting an example attack goal and scenarios in a real environment. The attack simulator successfully performed five attack techniques to gain administrator privileges.

• Journal of the Korea Society for Simulation
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• v.12 no.2
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• pp.63-73
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• 2003

The major objective of this paper is to propose the method of attacker and host modeling for cyber-attack simulation. In the security modeling and simulation for information assurance, it is essential the modeling of attacker that is able to generate various cyber-attack scenarios as well as the modeling of host, which is able to represent behavior on attack concretely The security modeling and simulation, which was announced by Cohen, Nong Ye and etc., is too simple to concretely analyze attack behavior on the host. And, the attacker modeling, which was announced by CERT, Laura and etc., is impossible to represent complex attack excepting fixed forms. To deal with this problem, we have accomplished attacker modeling by adopted the rule-based SES which integrates the existing SES with rule-based expert system for synthesis and performed host modeling by using the DEVS formalism. Our approach is to show the difference from others in that (ⅰ) it is able to represent complex and repetitive attack, (ⅱ) it automatically generates the cyber-attack scenario suitable on the target system, (ⅲ) it is able to analyze host's behavior of cyber attack concretely. Simulation tests performed on the sample network verify the soundness of proposed method.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.138-145
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• 2019

With the application of digital technology to safety-critical infrastructures, cyber-attacks have emerged as one of the new dangerous threats. In safety-critical infrastructures such as a nuclear power plant (NPP), a cyber-attack could have serious consequences by initiating dangerous events or rendering important safety systems unavailable. Since a cyber-attack is conducted intentionally, numerous possible cases should be considered for developing a cyber security system, such as the attack paths, methods, and potential target systems. Therefore, prior to developing a risk-informed cyber security strategy, the importance of cyber-attacks and significant critical digital assets (CDAs) should be analyzed. In this work, an importance analysis method for cyber-attacks on an NPP was proposed using the probabilistic safety assessment (PSA) method. To develop an importance analysis framework for cyber-attacks, possible cyber-attacks were identified with failure modes, and a PSA model for cyber-attacks was developed. For case studies, the quantitative evaluations of cyber-attack scenarios were performed using the proposed method. By using quantitative importance of cyber-attacks and identifying significant CDAs that must be defended against cyber-attacks, it is possible to develop an efficient and reliable defense strategy against cyber-attacks on NPPs.

• Journal of IKEEE
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• v.24 no.2
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• pp.669-672
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• 2020

In this paper, we analyzed the characteristics of cyber attacks and major threat scenarios that could occur around intelligent building management Systems(IBS) by cyber attack security threats against cyber physics systems. Generally determined that lowering the likelihood of aggression against predictable threats would be a more realistic approach to attack response. The countermeasures against this need to be applied to multi-layered defense systems, and three alternatives were proposed: preliminary cyber safety diagnosis for protection targets and the establishment of mobile security control systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2186-2203
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• 2020

Security administrators of companies and organizations need to come up with proper countermeasures against cyber-attacks considering infrastructures and security policies in their possession. In order to develop and verify such countermeasures, the administrators should be able to reenact both cyber-attacks and defenses. Simulations can be useful for the reenactment by overcoming its limitations including high risk and cost. If the administrators are able to design various scenarios of cyber-attacks and to develop simulation models from their viewpoints, they can simulate desired situations and observe the results more easily. It is challenging to simulate cyber-security issues, because there is lack of theoretical basis for modeling a wide range of the security field as well as pre-defined basic components used to model cyber-attacks. In this paper, we propose a modeling method for cyber-security simulations by developing a basic component and a composite model, called Abstracted Cyber-Security Unit Model (ACSUM) and Abstracted Cyber-security SIMulation model (ACSIM), respectively. The proposed models are based on DEVS(Discrete Event systems Specification) formalism, a modeling theory for discrete event simulations. We develop attack scenarios by sequencing attack behaviors using ACSUMs and then model ACSIMs by combining and abstracting the ACSUMs from a security perspective. The concepts of ACSUM and ACSIM enable the security administrators to simulate numerous cyber-security issues from their viewpoints. As a case study, we model a worm scenario using ACSUM and simulate three types of simulation models based on ACSIM from a different security perspective.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.112-118
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• 2023

As technology advances, the need for enhanced preparedness against cyber-attacks becomes an increasingly critical problem. Therefore, it is imperative to consider various circumstances and to prepare for cyber-attack strategic technology. This paper proposes a method to solve network security problems by applying reinforcement learning to cyber-security. In general, traditional static cyber-security methods have difficulty effectively responding to modern dynamic attack patterns. To address this, we implement cyber-attack scenarios such as 'Tiny Alpha' and 'Small Alpha' and evaluate the performance of various reinforcement learning methods using Network Attack Simulator, which is a cyber-attack simulation environment based on the gymnasium (formerly Open AI gym) interface. In addition, we experimented with different RL algorithms such as value-based methods (Q-Learning, Deep-Q-Network, and Double Deep-Q-Network) and policy-based methods (Actor-Critic). As a result, we observed that value-based methods with discrete action spaces consistently outperformed policy-based methods with continuous action spaces, demonstrating a performance difference ranging from a minimum of 20.9% to a maximum of 53.2%. This result shows that the scheme not only suggests opportunities for enhancing cybersecurity strategies, but also indicates potential applications in cyber-security education and system validation across a large number of domains such as military, government, and corporate sectors.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.133-140
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• 2015

C-ITS is a system that uses bidirectional communication between two vehicles or infrastructures to control traffic more conveniently, and safely. If C-ITS security is not properly prepared, it can cause traffic congestions and fatal traffic accidents, and therefore can affect greatly on the driver's life. This paper proposes the prevention and response mechanisms based on the cyber attack scenarios that can be used to attack C-ITS.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.107-117
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• 2023

It must be possible to assess how combat actions taking place in cyberspace affect the military's major mission systems and weapon systems. In order to analyze the mission impact caused by a cyber attack through cyber M&S, the target mission system and cyber warfare elements must be built as a model and a scenario for simulation must be authored. Many studies related to mission impact analysis due to cyber warfare have been conducted focusing on the United States, and existing studies have authored separate scenarios for physical battlefields and cyber battlefields. It is necessary to build a simulation environment that combines a physical battlefield model and a cyber battlefield model, and be able to integrate and author mission scenarios and cyber attack/defense scenarios. In addition, the physical battlefield and cyber battlefield are different work areas, so authoring two types of scenarios for simulation is very complicated and time-consuming. In this paper, we propose a method of using mission system information to prepare the data needed for scenario authoring in advance and using the pre-worked data to author an integrated scenario. The proposed method is being developed by reflecting it in the design of the scenario authoring tool, and an integrated scenario authoring in the field of counter-fire warfare is being performed to prove the proposed method. In the future, by using a scenario authoring tool that reflects the proposed method, it will be possible to easily author an integrated scenario for mission impact analysis in a short period of time.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2034-2046
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• 2023

Industrial control systems in nuclear facilities are facing increasing cyber threats due to the widespread use of information and communication equipment. To implement cyber security programs effectively through the RG 5.71, it is necessary to quantitatively assess cyber risks. However, this can be challenging due to limited historical data on threats and customized Critical Digital Assets (CDAs) in nuclear facilities. Previous works have focused on identifying data flows, the assets where the data is stored and processed, which means that the methods are heavily biased towards information security concerns. Additionally, in nuclear facilities, cyber threats need to be analyzed from a safety perspective. In this study, we use the system theoretic process analysis to identify system-level threat scenarios that could violate safety constraints. Instead of quantifying the likelihood of exploiting vulnerabilities, we quantify Security Control Measures (SCMs) against the identified threat scenarios. We classify the system and CDAs into four consequence-based classes, as presented in NEI 13-10, to analyze the adversary impact on CDAs. This allows for the ranking of identified threat scenarios according to the quantified SCMs. The proposed framework enables stakeholders to more effectively and accurately rank cyber risks, as well as establish security and response strategies.