• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1662-1669
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• 2020

Google cloud includes data uploaded and synchronized by users, as well as synchronization history of all cloud services, users' smartphone usage, and location information. Therefore, Google cloud data can be useful for digital forensics from a user behavior analysis perspective. Through this paper, we have identified the types of cloud data that can be acquired using Google's Takeout service and developed a tool that can be usefully utilized in digital forensics research and investigation by screening and analyzing the data required for analyzing user behavior. Because Google cloud data is synchronized through Google accounts regardless of the type of computing device, Google service data used on various devices such as PCs, smartphones, and tablet PCs can be acquired through Google accounts without the device. Therefore, the results of this paper's research are expected to be very useful for digital forensics research and investigation in the current situation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.3
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• pp.591-603
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• 2018

Windows Event Log is a format that records system log in Windows operating system and methodically manages information about system operation. An event can be caused by system itself or by user's specific actions, and some event logs can be used for corporate security audits, malware detection and so on. In this paper, we choose actions related to corporate security audit and malware detection (External storage connection, Application install, Shared folder usage, Printer usage, Remote connection/disconnection, File/Registry manipulation, Process creation, DNS query, Windows service, PC startup/shutdown, Log on/off, Power saving mode, Network connection/disconnection, Event log deletion and System time change), which can be detected through event log analysis and classify event IDs that occur in each situation. Also, the existing event log tools only include functions related to the EVTX file parse and it is difficult to track user's behavior when used in a forensic investigation. So we implemented new analysis tool in this study which parses EVTX files and user behaviors.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.293-302
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• 2015

With the attack information collected during SMS phishing investigation, this paper will propose SMS phishing profiling model applying criminal profiling. Law enforcement agencies have used signature analysis by apk file hash and analysis of C&C IP address inserted in the malware. However, recently law enforcement agencies are facing the challenges such as signature diversification or code obfuscation. In order to overcome these problems, this paper examined 169 criminal cases and found out that 89% of serial number in cert.rsa and 80% of permission file was reused in different cases. Therefore, the proposed SMS phishing profiling model is mainly based on signature serial number and permission file hash. In addition, this model complements the conventional file hash clustering method and uses code similarity verification to ensure reliability.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.489-499
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• 2017

MS office is a office software which is widely used in the world. The OOXML format has been applied to the document structure from MS office 2007 to the newest version. In this regard, the method of data concealing, which is a representative anti-forensic act has been researched and developed, so the method of detecting concealed data is very important to the digital forensic investigation. In this paper, we present an improved data concealing method bypassing the previewers detecting methods for OOXML formatted MS office documents. In addition, we show concealment of the internal data like sheets and slides for MS office 2013 Excel and PowerPoint, and suggest an improved detecting algorithm against this data concealing.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1373-1383
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• 2017

Deduplication is a function to effectively manage data and improve the efficiency of storage space. When the deduplication is applied to the system, it makes it possible to efficiently use the storage space by dividing the stored file into chunks and storing only unique chunk. However, the commercial digital forensic tool do not support the file system analysis, and the original file extracted by the tool can not be executed or opened. Therefore, in this paper, we analyze the process of generating chunks of data for a Windows Server 2012 system that can apply deduplication, and the structure of the resulting file(Chunk Storage). We also analyzed the case where chunks that are not covered in the previous study are compressed. Based on these results, we propose the method to collect deduplicated data and reconstruct the original file for digital forensic investigation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.39-48
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• 2015

As a growing number of people are concerned about the protection of personal information, the use of encryption solution has been increased. In addition, with the end of support for Windows XP and the improvement of operating system, the use of the Full Disk Encryption solution like Bitlocker will be increased. Therefore, it is necessary to consider countermeasures against Full Disk Encryption for the future digital forensic investigation. This paper provides the digital evidence acquisition procedure that responds to the Full Disk Encryption environment and introduces the countermeasures and detection tool against Full Disk Encryption solutions that are widely used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2595-2601
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• 2013

Currently, under being related with confiscation method of digital store medium from the court of justice, "the sorting confiscation method of principle, the exceptional medium confiscation method" from in section3 no.106 of the criminal procedure code disregard the actual fields of investigation. What is more, there are many difficulties to execute cases by observing this for the achievement of confiscation purpose. At this point, I present the problems of the present confiscation search method and the desirable scene confiscation search method and the improvement program under the new technology circumstance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.4
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• pp.671-685
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• 2023

By applying artificial intelligence to image editing technology, it has become possible to generate high-quality images with minimal traces of manipulation. However, since these technologies can be misused for criminal activities such as dissemination of false information, destruction of evidence, and denial of facts, it is crucial to implement strong countermeasures. In this study, image file and mobile forensic artifacts analysis were conducted for detecting image manipulation. Image file analysis involves parsing the metadata of manipulated images and comparing them with a Reference DB to detect manipulation. The Reference DB is a database that collects manipulation-related traces left in image metadata, which serves as a criterion for detecting image manipulation. In the mobile forensic artifacts analysis, packages related to image editing tools were extracted and analyzed to aid the detection of image manipulation. The proposed methodology overcomes the limitations of existing graphic feature-based analysis and combines with image processing techniques, providing the advantage of reducing false positives. The research results demonstrate the significant role of such methodology in digital forensic investigation and analysis. Additionally, We provide the code for parsing image metadata and the Reference DB along with the dataset of manipulated images, aiming to contribute to related research.

• Convergence Security Journal
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• v.23 no.5
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• pp.45-55
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• 2023

With the widespread use of digital devices, anonymous communication technologies such as the dark web and deep web are becoming increasingly popular for criminal activity. Because these technologies leave little local data on the device, they are difficult to track using conventional crime investigation techniques. The United States and the United Kingdom have enacted laws and developed systems to address this issue, but South Korea has not yet taken any significant steps. This paper proposes a new blockchain-based crime investigation method that uses physical memory data analysis to track the behavior of anonymous network users. The proposed method minimizes infringement of basic rights by only collecting physical memory data from the device of the suspected user and storing the tracking information on a blockchain, which is tamper-proof and transparent. The paper evaluates the effectiveness of the proposed method using a simulation environment and finds that it can track the behavior of dark website users with a residual rate of 77.2%.

• The Journal of Korean Association of Computer Education
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• v.17 no.3
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• pp.75-84
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• 2014

It is a current situation that a large number of physical and financial damages are increasing due to the growth of intellectual cyber crime and unexpected Internet incidents year by year. In the large scale security incidents, digital forensics techniques for computer crime investigations are essential to secure a place in the field. However, qualified digital forensics investigators who complete with digital security technology are practically insufficient in domestic. In this paper, as one of developing human resources plans regarding to scientific investigation of Internet security incidents, an undergraduate curriculum per stage in digital forensics was proposed. For the effective curriculum per stage, the interviews, group discussion on focused group of existing digital forensics investigators and related research were performed to select curriculum, and then the level of difficulty and practical suitability on each subject designed were analyzed through survey and interview to current investigators and security professionals. After collating the survey, the digital forensic curriculum per level was designed to highly adaptable workforce for the future for working and positive suggestions and proposals are addressed.