start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210119 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Web access monitoring mechanism via Android WebView for threat analysis en-subtitle= kn-subtitle= en-abstract= kn-abstract=Many Android apps employ WebView, a component that enables the display of web content in the apps without redirecting users to web browser apps. However, WebView might also be used for cyberattacks. Moreover, to the best of our knowledge, although some countermeasures based on access control have been reported for attacks exploiting WebView, no mechanism for monitoring web access via WebView has been proposed and no analysis results focusing on web access via WebView are available. In consideration of this limitation, we propose a web access monitoring mechanism for Android WebView to analyze web access via WebView and clarify attacks exploiting WebView. In this paper, we present the design and implementation of this mechanism by modifying Chromium WebView without any modifications to the Android framework or Linux kernel. The evaluation results of the performance achieved on introducing the proposed mechanism are also presented here. Moreover, the result of threat analysis of displaying a fake virus alert while browsing websites on Android is discussed to demonstrate the effectiveness of the proposed mechanism. en-copyright= kn-copyright= en-aut-name=ImamuraYuta en-aut-sei=Imamura en-aut-mei=Yuta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OritoRintaro en-aut-sei=Orito en-aut-mei=Rintaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UekawaHiroyuki en-aut-sei=Uekawa en-aut-mei=Hiroyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ChaikaewKritsana en-aut-sei=Chaikaew en-aut-mei=Kritsana kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=LeelaprutePattara en-aut-sei=Leelaprute en-aut-mei=Pattara kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SatoMasaya en-aut-sei=Sato en-aut-mei=Masaya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamauchiToshihiro en-aut-sei=Yamauchi en-aut-mei=Toshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Faculty of Engineering, Kasetsart University kn-affil= affil-num=5 en-affil=Faculty of Engineering, Kasetsart University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology kn-affil= affil-num=7 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Android kn-keyword=Android en-keyword=WebView kn-keyword=WebView en-keyword=Web access monitoring kn-keyword=Web access monitoring en-keyword=Web security kn-keyword=Web security en-keyword=Threat analysis kn-keyword=Threat analysis en-keyword=Fake virus alert kn-keyword=Fake virus alert END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=338 end-page=349 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200820 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Improvement and Evaluation of a Function for Tracing the Diffusion of Classified Information on KVM en-subtitle= kn-subtitle= en-abstract= kn-abstract=The increasing amount of classified information currently being managed by personal computers has resulted in the leakage of such information to external computers, which is a major problem. To prevent such leakage, we previously proposed a function for tracing the diffusion of classified information in a guest operating system (OS) using a virtual machine monitor (VMM). The tracing function hooks a system call in the guest OS from the VMM, and acquiring the information. By analyzing the information on the VMM side, the tracing function makes it possible to notify the user of the diffusion of classified information. However, this function has a problem in that the administrator of the computer platform cannot grasp the transition of the diffusion of classified processes or file information. In this paper, we present the solution to this problem and report on its evaluation. en-copyright= kn-copyright= en-aut-name=MoriyamaHideaki en-aut-sei=Moriyama en-aut-mei=Hideaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamauchiToshihiro en-aut-sei=Yamauchi en-aut-mei=Toshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SatoMasaya en-aut-sei=Sato en-aut-mei=Masaya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TaniguchiHideo en-aut-sei=Taniguchi en-aut-mei=Hideo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=National Institute of Technology, Ariake College kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=791 cd-vols= no-issue= article-no= start-page=139598 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200618 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The effect of precipitations (NbC and carbide) in Fe?C?Mn-xNb steels on hydrogen embrittlement characteristics en-subtitle= kn-subtitle= en-abstract= kn-abstract=Hydrogen embrittlement (HE) characteristics in Fe?C?Mn-xNb steels were examined via various analyses, including electron backscatter diffraction analysis, scanning transmission electron microscopy and three-dimensional atom-probe tomography. For the investigation, the steel samples were prepared with varying Nb contents and heat treatment processes. The material properties of steel samples that were subjected to: (i) water quenching and (ii) quenching and tempering at 170 C for 20 min, were determined to be nearly similar, although different degrees of HE were detected. After the tempering process, -carbide precipitated clearly in the matrix, which could act as a trapping site for hydrogen atoms and lead to improved HE resistance. Moreover, with addition of Nb, niobium base precipitates (e.g., NbC) with a diameter of a few nanometers were obtained in the martensite matrix, which could also function as hydrogen trapping sites. There was slight improvement in the HE resistance with NbC. Hydrogen-assisted failure mechanisms under both static and cyclic loading were observed with intergranular brittle cracking for the water quenched sample, even though the brittle and ductile mix failure mode was detected for the sample after the quenching and tempering process. en-copyright= kn-copyright= en-aut-name=OkayasuMitsuhiro en-aut-sei=Okayasu en-aut-mei=Mitsuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SatoMasaya en-aut-sei=Sato en-aut-mei=Masaya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IshidaDaiki en-aut-sei=Ishida en-aut-mei=Daiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SenumaTakehide en-aut-sei=Senuma en-aut-mei=Takehide kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Steel kn-keyword=Steel en-keyword=Hydrogen embrittlement; kn-keyword=Hydrogen embrittlement; en-keyword=Trapping site kn-keyword=Trapping site en-keyword=Niobium carbide; kn-keyword=Niobium carbide; en-keyword=-carbide kn-keyword=-carbide END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=1 end-page=10 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190528 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Design and implementation of hiding method for file manipulation of essential services by system call proxy using virtual machine monitor en-subtitle= kn-subtitle= en-abstract= kn-abstract= Security or system management software is essential for keeping systems secure. To deter attacks on essential services, hiding information related to essential services is helpful. This paper describes the design, the implementation, and the evaluation of a method to make files invisible to all services except their corresponding essential services and provides access methods to those files in a virtual machine (VM). In the proposed method, the virtual machine monitor (VMM) monitors the system call, which invoked by an essential process to access essential files, and requests proxy execution to the proxy process on another VM. The VMM returns the result and skips the execution of the original system call on the protection target VM. Thus, access to essential files by the essential service is skipped on the protection target VM, but the essential service can access the file content. en-copyright= kn-copyright= en-aut-name=SatoMasaya en-aut-sei=Sato en-aut-mei=Masaya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TaniguchiHideo en-aut-sei=Taniguchi en-aut-mei=Hideo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamauchiToshihiro en-aut-sei=Yamauchi en-aut-mei=Toshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=virtual machine monitor kn-keyword=virtual machine monitor en-keyword=file manipulation kn-keyword=file manipulation en-keyword=system call proxy kn-keyword=system call proxy en-keyword=essential services kn-keyword=essential services END