Covert Channels in MLS Systems (1)

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● An Overview of the History and Current Trends in Covert Channel Technology
● Outline
● Information Flows and Multi-level Security (MLS) (1)
● Information Flows and MLS (2)
● Information Flows and MLS (3)
● Covert Channels in MLS Systems (1)
● Covert Channels in MLS Systems (2)
● Covert Channels in MLS Systems (3)
● Covert Channels in MLS Systems (4)
● Covert Channels in MLS Systems (5)
● Properties of Covert Channels
● Prevention, Detection, Effectiveness
● Modern Covert Channels (1)
● Modern Covert Channels (2)
● A Framework (1)
● A Framework (2)
● A Framework (3)
● Wardens (1)
● Wardens (2)
● Storage Channels (1)
● Storage Channels (2)
● Storage Channels (3)
● Storage Channels (4)
● Storage Channels – Detection and Mitigation (1)
● Storage Channels – Detection and Mitigation (2)
● Timing Channels (1)
● Timing Channels (2)
● Constructing a timing channel (1)
● Constructing a timing channel (2)
● Some issues with the timing channel
● Timing interval of the timing channel
● Synchronisation of the timing channel
● Timing channels – Detection and Mitigation
● Conclusion
● Thank you!

نوع زبان: انگلیسی حجم: 0.41 مگا بایت
نوع فایل: اسلاید پاورپوینت تعداد اسلایدها: 35 صفحه
سطح مطلب: نامشخص پسوند فایل: ppt
گروه موضوعی: زمان استخراج مطلب: 2019/05/15 11:23:12

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عبارات مهم استفاده شده در این مطلب

channel, ., covert, system, information, flow, security, ml, storage, level, timing, network,

توجه: این مطلب در تاریخ 2019/05/15 11:23:12 به صورت خودکار از فضای وب آشکار توسط موتور جستجوی پاورپوینت جمع آوری شده است و در صورت اعلام عدم رضایت تهیه کننده ی آن، طبق قوانین سایت از روی وب گاه حذف خواهد شد. این مطلب از وب سایت زیر استخراج شده است و مسئولیت انتشار آن با منبع اصلی است.

http://www.isg.rhul.ac.uk/~prai175/ISGStudentSem07/CovertChannels.ppt

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عبارات پرتکرار و مهم در این اسلاید عبارتند از: channel, ., covert, system, information, flow, security, ml, storage, level, timing, network,

مشاهده محتوای متنیِ این اسلاید ppt

مشاهده محتوای متنیِ این اسلاید ppt

an overview of the history and current trends in covert channel technology nicholas hoare isg phd seminar thursday ۲۸th february outline information flows and multi level security mls covert channels in multi level security systems properties of covert channels prevention detection effectiveness modern covert channels a framework wardens network storage channels network timing channels conclusion information flows and multi level security mls ۱ an information flow policy is typically designed to preserve the confidentiality and or integrity of data within a computer system. in terms of confidentiality the policy tries to prevent the flow of information to those users not authorised to receive it. in multi level security mls systems the following is important to allow information flows between users of the system who have sufficient security clearances and to prevent flows to those that do not. information flows and mls ۲ if all possible information flows can be identified then these flows can be restricted such that the goals of the security policy are preserved. if it is not possible to identify all such flows then there is the potential for information to flow in an unauthorised manner. if information can flow within a system in an unauthorised manner then the security boundaries defined by the security policy can be violated. information flows and mls ۳ it is therefore possible even in systems that have security policies as well as discretionary and mandatory access controls that information may be able to flow in a manner not expected by the designers of the system. it has been shown that a limitation of the bell lapadula model is that it cannot constrain information flow in such a way to prevent the establishment of these types of channels. covert channels in mls systems ۱ a channel can be defined as a communication path by which information can flow within a computer system. an overt channel is one which is designed for the authorised transfer of data. a covert channel is by contrast a path that can allow information to flow in a manner that violates the security policy of a system allowing the transfer of information by an unauthorised process. covert channels in mls systems ۲ unless all possible channels can be identified there is the potential for covert channels to exist in all systems where mls is used. the trusted computer security evaluation criteria tcsec is a standard which allows computer systems to gain a security rating based upon the security that they provide. tcsec recognises the existence of such channels and certain ratings require the analysis of such channels. covert channels in mls systems ۳ tcsec recognises two types of covert channel that can exist in a system. the first is the covert storage channel a covert storage channel is a covert channel that involves the direct or indirect writing of a storage location by one process and the direct or indirect reading of the storage location by another process. covert storage channels typically involve a finite resource e.g. sectors on a disk that is shared by two subjects at different security levels. examples shared file system. network protocols. covert channels in mls systems ۴ the second type of channel that tcsec recognises is the covert timing channel a covert timing channel is a covert channel in which one process signals information to another by modulating its own use of system resources e.g. cpu time in such a way that this manipulation affects the real response time observed by the second process. examples availability of a resource at certain times. packet inter arrival times of internet traffic. covert channels in mls systems ۵ in terms of tcsec there are several divisions of security that systems can be awarded. d c b and a where a is the highest. for a b۲ rating the occurrence and bandwidth of a storage channel must be analysed and for a b۳ rating the same for a timing channel. one of the goals of tcsec in analysing these channels is to be able to monitor and maintain the capacity of the channel below maximum acceptable levels. this highlights the fact that covert channels are seen as a real practical threat to the security of computer systems. properties of covert channels the main properties of a covert channel are existence. capacity. covertness. a covert channel can either be noiseless – this type of channel is simply shared by the covert communicators. noisy – has the addition of other communicating traffic. prevention detection effectiveness has been shown that prevention of channel is very difficult. more desirable to be able to detect channel and reduce the effectiveness bandwidth of the channel. if bandwidth reduced below acceptable level then monitoring not necessary. various methods proposed to eliminate or reduce channels. will be mentioned later. modern covert channels ۱ the interconnection of networks has meant covert channels present even greater challenge. emergence of high speed communication channels has meant the potential for higher capacity channels. reports indicate possibility of covert channels to leak information out of protected networks across internet. allow groups to communicate and pass information without outside knowledge. coordinate attacks such as distributed denial of service ddos attacks. modern covert channels ۲ the increased use of internetworking for communication has meant that covert channels can now be used to transfer information using arbitrary internet traffic. network storage channels have received much more attention than the timing channels. several reasons for this have been highlighted with the main ones being due to the nature of timing channels in networks information is usually transferred by the monitoring of packet inter arrival times which means that it is not trivial to be able to achieve good synchronisation between sender and receiver and the bandwidth of timing channels tends to be less than that of a storage channel. a framework ۱ proposed by lucena pease yadollahpour and chapin ۲ ۴ . alice and bob …

کلمات کلیدی پرکاربرد در این اسلاید پاورپوینت: channel, ., covert, system, information, flow, security, ml, storage, level, timing, network,

این فایل پاورپوینت شامل 35 اسلاید و به زبان انگلیسی و حجم آن 0.41 مگا بایت است. نوع قالب فایل ppt بوده که با این لینک قابل دانلود است. این مطلب برگرفته از سایت زیر است و مسئولیت انتشار آن با منبع اصلی می باشد که در تاریخ 2019/05/15 11:23:12 استخراج شده است.

http://www.isg.rhul.ac.uk/~prai175/ISGStudentSem07/CovertChannels.ppt

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