Guide_to_Computer_Network_Security.pdf - Computer Communications and Networks The Computer Communications and Networks series is a range of textbooks

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Unformatted text preview: Computer Communications and Networks The Computer Communications and Networks series is a range of textbooks, monographs and handbooks. It sets out to provide students, researchers and nonspecialists alike with a sure grounding in current knowledge, together with comprehensible access to the latest developments in computer communications and networking. Emphasis is placed on clear and explanatory styles that support a tutorial approach so that even the most complex of topics is presented in a lucid and intelligible manner. For other titles published in this series, go to Joseph Migga Kizza A Guide to Computer Network Security 13 2 Joseph Migga Kizza, PhD University of Tennessee-Chattanooga Department of Computer Science 615 McCallie Ave. Chattanooga TN 37403 326 Grote Hall USA [email protected] Series Editor Professor A.J. Sammes, BSc, MPhil, PhD, FBCS, CEng CISM Group, Cranfield University, RMCS, Shrivenham, Swindon SN6 8LA,UK CCN Series ISSN 1617-7975 ISBN 978-1-84800-916-5 e-ISBN 978-1-84800-917-2 DOI 10.1007/978-1-84800-917-2 Library of Congress Control Number: 2008942999 © Springer-Verlag London Limited 2009 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science +Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper springer.com To the Trio: Immaculate, Josephine, and Florence Preface If we are to believe in Moore’s law, then every passing day brings new and advanced changes to the technology arena. We are as amazed by miniaturization of computing devices as we are amused by their speed of computation. Everything seems to be in flux and moving fast. We are also fast moving towards ubiquitous computing. To achieve this kind of computing landscape, new ease and seamless computing user interfaces have to be developed. Believe me, if you mature and have ever program any digital device, you are, like me, looking forward to this brave new computing landscape with anticipation. However, if history is any guide to use, we in information security, and indeed every computing device user young and old, must brace themselves for a future full of problems. As we enter into this world of fast, small and concealable ubiquitous computing devices, we are entering fertile territory for dubious, mischievous, and malicious people. We need to be on guard because, as expected, help will be slow coming because first, well trained and experienced personnel will still be difficult to get and those that will be found will likely be very expensive as the case is today. Secondly, the security protocols and best practices will, as it is today, keep changing at a first rate which may warrant network administrators to constantly changing them. Thirdly, as the case is today, it will be extremely difficult to keep abreast of the many new vulnerabilities and patches to them. In other words, the computing landscape will change for sure on one side and remain the same on the other. For these reasons, we need to remain vigilant with better, if not advanced computer and information security protocols and best practices because the frequency of computer network attacks and the vulnerability of computer network systems will likely not abet, rather they are likely to increase as before. More efforts in developing adaptive and scalable security protocols and best practices and massive awareness, therefore, are needed to meet this growing challenge and bring the public to a level where they can be active and safe participants in the brave new worlds of computing. This guide is a comprehensive volume touching not only on every major topic in computing and information security and assurance, but it also introduces new computing technologies like wireless sensor networks, a wave of the future, where vii viii Preface security is likely to be a major issues. It is intended to bring massive education and awareness of security issues and concerns in cyberspace in general and the computing world in particular, their benefits to society, the security problems and the dangers likely to be encountered by the users, and be a pathfinder as it initiates a dialog towards developing better algorithms, protocols, and best practices that will enhance security of computing systems in the anticipated brave new world. It does this comprehensively in four parts and twenty-two chapters. Part I gives the reader an understanding of the working of and the security situation of computer networks. Part II builds on this knowledge and exposes the reader to the prevailing security situation based on a constant security threat. It surveys several security threats. Part III, the largest, forms the core of the guide and presents to the reader most of the best practices and solutions that are currently in use. Part IV is for projects. In addition to the algorithms, protocols, and solutions, several products and services are given for each security item under discussion. In summary, the guide attempts to achieve the following objectives: 1 Educate the public about cyberspace security in general terms and computer systems security in particular, with reference to the Internet, 2 Alert the public to the magnitude of computer network vulnerabilities, weaknesses, and loopholes inherent in the computer network infrastructure 3 Bring to the public attention effective security solutions and best practice, expert opinions on those solutions, and the possibility of ad-hoc solutions 4 Look at the roles legislation, regulation, and enforcement play in computer network security efforts 5 Finally, initiate a debate on developing effective and comprehensive algorithms, protocols, and best practices for information security. Since the guide covers a wide variety of security topics, algorithms, solutions, and best practices, it is intended to be both a teaching and a reference tool for all interested in learning about computer network security issues and available techniques to prevent information systems attacks. The depth and thorough discussion and analysis of most of the computer network security issues, together with the discussion of security algorithms, and solutions given, makes the guide a unique reference source of ideas for computer network security personnel, network security policy makers, and those reading for leisure. In addition, the guide provokes the reader by raising valid legislative, legal, social, and ethical security issues, including the increasingly diminishing line between individual privacy and the need for collective and individual security. The guide targets college students in computer science, information science, technology studies, library sciences, engineering, and to a lesser extent students in the arts and sciences who are interested in information technology. In addition, students in information management sciences will find the guide particularly helpful. Practitioners, especially those working in information-intensive areas, will likewise find the guide a good reference source. It will also be valuable to those interested in any aspect of information security and assurance and those simply wanting to become cyberspace literates. Preface ix Book Resources There are two types of exercises at the end of chapter: easy and quickly workable exercises whose responses can be easily spotted from the proceeding text; and more though provoking advanced exercises whole responses may require research outside the content of this book. Also chapter 22 is devoted to lab exercises. There are three types of lab exercises: weekly or bi-weekly assignments that can be done easily with either reading or using readily available software and hardware tools; slightly harder semester long projects that may require extensive time, collaboration, and some research to finish them successfully; and hard open research projects that require a lot of thinking, take a lot of time, and require extensive research. We have tried as much as possible, throughout the guide, to use open source software tools. This has two consequences to it: one, it makes the guide affordable keeping in mind the escalating proprietary software prices; and two, it makes the content and related software tools last longer because the content and corresponding exercises and labs are not based on one particular proprietary software tool that can go out anytime. Instructor Support Materials As you consider using this book, you may need to know that we have developed materials to help you with your course. The help materials for both instructors and students cover the following areas: • Syllabus. There is a suggested syllabus for the instructor. • Instructor PowerPoint slides. These are detailed enough to help the instructor, especially those teaching the course for the first time. • Answers to selected exercises at the end of each chapter • Laboratory. Since network security is a hands-on course, students need to spend a considerable amount of time on scheduled laboratory exercises. The last chapter of the book contains several laboratory exercises and projects. The book resource center contains several more and updates • Instructor manual. These will guide the instructor in the day to day job of getting materials ready for the class. • Student laboratory materials. Under this section, we will be continuously posting the latest laboratory exercises, software, and challenge projects. These materials can be found at the publisher’s website at and at the author’s site at Faculty/Joseph-Kizza/ Chattanooga, Tennessee, USA October, 2008. Joseph Migga Kizza Contents Part I 1 Understanding Computer Network Security Computer Network Fundamentals ................................................................3 1.1 Introduction ..............................................................................................3 1.2 Computer Network Models ......................................................................4 1.3 Computer Network Types ........................................................................5 1.3.1 Local Area Networks (LANs).......................................................5 1.3.2 Wide Area Networks (WANs) ......................................................6 1.3.3 Metropolitan Area Networks (MANs) ..........................................6 1.4 Data Communication Media Technology................................................. 7 1.4.1 Transmission Technology ............................................................. 7 1.4.2 Transmission Media ....................................................................10 1.5 Network Topology..................................................................................13 1.5.1 Mesh ...........................................................................................13 1.5.2 Tree .............................................................................................13 1.5.3 Bus ..............................................................................................14 1.5.4 Star ..............................................................................................15 1.5.5 Ring ............................................................................................15 1.6 Network Connectivity and Protocols .....................................................16 1.6.1 Open System Interconnection (OSI) Protocol Suite ...................18 1.6.2 Transport Control Protocol/Internet Protocol (TCP/IP) Model ..........................................................................19 1.7 Network Services ...................................................................................22 1.7.1 Connection Services ...................................................................22 1.7.2 Network Switching Services ......................................................24 1.8 Network Connecting Devices.................................................................26 1.8.1 LAN Connecting Devices ...........................................................26 1.8.2 Internetworking Devices.............................................................30 1.9 Network Technologies............................................................................34 1.9.1 LAN Technologies ......................................................................35 1.9.2 WAN Technologies ..................................................................... 37 1.9.3 Wireless LANs ............................................................................39 1.10 Conclusion..............................................................................................40 xi xii Contents Exercises ...............................................................................................................40 Advanced Exercises .............................................................................................. 41 References ............................................................................................................. 41 2 Understanding Computer Network Security .............................................43 2.1 Introduction ............................................................................................43 2.1.1 Computer Security......................................................................44 2.1.2 Network Security........................................................................45 2.1.3 Information Security ..................................................................45 2.2 Securing the Computer Network ...........................................................45 2.2.1 Hardware ....................................................................................46 2.2.2 Software .....................................................................................46 2.3 Forms of Protection................................................................................46 2.3.1 Access Control............................................................................46 2.3.2 Authentication ............................................................................48 2.3.3 Confidentiality ............................................................................48 2.3.4 Integrity ......................................................................................49 2.3.5 Nonrepudiation ...........................................................................49 2.4 Security Standards .................................................................................50 2.4.1 Security Standards Based on Type of Service/Industry ............. 51 2.4.2 Security Standards Based on Size/Implementation ....................54 2.4.3 Security Standards Based on Interests .......................................55 2.4.4 Best Practices in Security ...........................................................56 Exercises ...............................................................................................................58 Advanced Exercises ..............................................................................................58 References .............................................................................................................59 Part II 3 Security Challenges to Computer Networks Security Threats to Computer Networks ....................................................63 3.1 Introduction ............................................................................................63 3.2 Sources of Security Threats ...................................................................64 3.2.1 Design Philosophy ......................................................................65 3.2.2 Weaknesses in Network Infrastructure and Communication Protocols .................................................................................65 3.2.3 Rapid Growth of Cyberspace .....................................................68 3.2.4 The Growth of the Hacker Community ......................................69 3.2.5 Vulnerability in Operating System Protocol...............................78 3.2.6 The Invisible Security Threat – The Insider Effect ....................79 Contents 3.3 3.4 3.5 3.6 xiii 3.2.7 Social Engineering .....................................................................79 3.2.8 Physical Theft .............................................................................80 Security Threat Motives .........................................................................80 3.3.1 Terrorism ....................................................................................80 3.3.2 Military Espionage ..................................................................... 81 3.3.3 Economic Espionage .................................................................. 81 3.3.4 Targeting the National Information Infrastructure .....................82 3.3.5 Vendetta/Revenge .......................................................................82 3.3.6 Hate (National Origin, Gender, and Race) .................................83 3.3.7 Notoriety .....................................................................................83 3.3.8 Greed ..........................................................................................83 3.3.9 Ignorance ....................................................................................83 Security Threat Management .................................................................83 3.4.1 Risk Assessment .........................................................................84 3.4.2 Forensic Analysis .......................................................................84 Security Threat Correlation ....................................................................84 3.5.1 Threat Information Quality.........................................................85 Security Threat Awareness .....................................................................85 Exercises ...............................................................................................................86 Advanced Exercises .............................................................................................. 87 References .............................................................................................................88 4 Computer Network Vulnerabilities ..............................................................89 4.1 Definition ...............................................................................................89 4.2 Sources of Vulnerabilities ......................................................................89 4.2.1 Design Flaws ..............................................................................90 4.2.2 Poor Security Management ........................................................93 4.2.3 Incorrect Implementation ...........................................................94 4.2.4 Internet Technology Vulnerability ..............................................95 4.2.5 Changing Nature of Hacker Technologies and Activities ..........99 4.2.6 Difficulty of Fixing Vulnerable Systems ..................................100 4.2.7 Limits of Effectiveness of Reactive Solutions ......................... 101 4.2.8 Social Engineering ...................................................................102 4.3 Vulnerability Assessment ...........................................................
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