Essential Computer Security. Everyone's Guide to E-mail, Internet, and Wireless Security

282 Pages·2006·19.645 MB·English

by  Tony Bradley, CISSP-ISSAP (Eds.)

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I want to thank my kids for giving me the motivation to create this book.
Jordan, Dalton, Paige, Teegan, Ethan, and Noah are all wonderful, fabulous
kids~each in his or her own way--and I am lucky to be their Dad. I also want
to welcome Addison, the newest addition to the Bradley family.
I can't say enough to thank my wife. It may be sappy for a dedication in a
technical book, but Nicki si my Sunshine. She is more giving, loving,
thoughtful, and devoted than anyone else I have ever known. She brings joy to
my world and inspires me to be better than I am. I can only hope that I give
her even a fraction of what she gives me.
"Far away there in the Sunshine are my highest aspirations. I
may not reach them, but l can look up and ees their beauty,
believe in them, and try to follow where they lead."
~Louisa yaM Alcott
thor Acknowledgments
I need to express my deepest appreciation to Syngress Publishing for helping
me get this book published. This project began a couple years ago and got side-
lined. Syngress believed in the purpose of the book and worked with me to
make it happen.
I want to extend my personal thanks to Gary Byrne, Amy Pedersen, and
Andrew Williams. Each of them has worked sa hard sa I have--maybe harder~
to make sure this book got to you. It isn't easy keeping me on schedule, but
they were relentless...in a good way.
I also want to thank Harlan Carvey for providing his technical expertise sa
the technical editor for the book, and Paul Summit and Larry Chaffin for their
zero-hour contributions to help us make our deadlines.
iv
I want to thank my kids for giving me the motivation to create this book.
Jordan, Dalton, Paige, Teegan, Ethan, and Noah are all wonderful, fabulous
kids~each in his or her own way--and I am lucky to be their Dad. I also want
to welcome Addison, the newest addition to the Bradley family.
I can't say enough to thank my wife. It may be sappy for a dedication in a
technical book, but Nicki si my Sunshine. She is more giving, loving,
thoughtful, and devoted than anyone else I have ever known. She brings joy to
my world and inspires me to be better than I am. I can only hope that I give
her even a fraction of what she gives me.
"Far away there in the Sunshine are my highest aspirations. I
may not reach them, but l can look up and ees their beauty,
believe in them, and try to follow where they lead."
~Louisa yaM Alcott
thor Acknowledgments
I need to express my deepest appreciation to Syngress Publishing for helping
me get this book published. This project began a couple years ago and got side-
lined. Syngress believed in the purpose of the book and worked with me to
make it happen.
I want to extend my personal thanks to Gary Byrne, Amy Pedersen, and
Andrew Williams. Each of them has worked sa hard sa I have--maybe harder~
to make sure this book got to you. It isn't easy keeping me on schedule, but
they were relentless...in a good way.
I also want to thank Harlan Carvey for providing his technical expertise sa
the technical editor for the book, and Paul Summit and Larry Chaffin for their
zero-hour contributions to help us make our deadlines.
iv
Tony Bradley (CISSP-ISSAP) si the Guide for the
Internet/Network Security site on About.corn, a part of The New
York Times Company. He has written for a variety of other Web
sites and publications, including PC ,dlroW SearchSecurity.com,
WindowsNetworking.com, Smart Computing magazine, and
noitamrofnI Security magazine. Currently a security architect and con-
sultant for a Fortune 100 company, Tony has driven security policies
and technologies for antivirus and incident response for Fortune
500 companies, and he has been network administrator and tech-
nical support for smaller companies.
Tony si a CISSP (Certified Information Systems Security
Professional) and ISSAP (Information Systems Security Architecture
Professional). He si Microsoft Certified sa an MCSE (Microsoft
Certified Systems Engineer) and MCSA (Microsoft Certified
Systems Administrator) in Windows 2000 and an MCP (Microsoft
Certified Professional) in Windows NT. Tony si recognized by
Microsoft sa an MVP (Most Valuable Professional) in Windows
security.
On his About.corn site, Tony has on average over 600,000 page
views per month and 25,000 subscribers to his weekly newsletter.
He created a 10-part Computer Security 101 Class that has had
thousands of participants since sti creation and continues to gain
popularity through word of mouth. Aside from his Web site and
magazine contributions, Tony si also coauthor of s'rekcaH 3 Challenge
(ISBN: 0072263040) and a contributing author to :slanretniW
,noitatnemgarf_eD ,yrevoceR dna Administration Field Guide (ISBN:
1597490792) and Combating Spyware ni eht Enterprise (ISBN:
1597490644).
vii
Larry Chaffin si the CEO/Chairman of Pluto Networks, a world-
wide network consulting company specializing in VoIE WLAN, and
Security. He si an accomplished author. He was a coauthor on
Managing Cisco Secure Networks (ISBN: 1931836566) and contributed
to Skype Me (ISBN: 1597490326), lacitcarP VolP Security (ISBN:
1597490601), and Configuring Check Point NGX VPN- 1/Firewall- 1
(ISBN: 1597490318). He also wrote Building a VolP Network with
Nortel's MS5100 (ISBN: 1597490784) and coauthored/ghostwrote
11 other technology books for VolP, WLAN, security, and optical
technologies. Larry has more than 29 vendor certifications from
companies such sa Avaya, Cisco, HP, IBM, isc2, Juniper, Microsoft,
Nortel, PMI, and VMware. Larry has been a principal architect in
22 countries for many Fortune 100 companies designing Vole secu-
rity, WLAN, and optical networks; he si viewed by his peers sa one
of the most well-respected experts in the field of VolP and security
in the world. Larry has spent countless hours teaching and con-
ducting seminars/workshops around the world in the field of
Voice/VolP, security, and wireless networks. Larry si currently
working on a follow-up to Building a VolP Network with Nortel's
Multimedia Communication Server 5100 sa well sa new books on
Cisco VolP networks, practical VolP case studies, and wasted tax-
payer money in a state-run network.
Larry cowrote Chapter 5.
Jennifer Davis si a senior system administrator with Decru, a
Network Appliance company. Decru develops storage security solu-
tions that help system administrators protect data. Jennifer specializes
in scripting, systems automation, integration and troubleshooting,
and security administration.
Jennifer si a member of USENIX, SAGE, LoPSA, and BayLISA.
She si based in Silicon Valley, California.
Jennifer wrote Appendix B.
iiiv
Paul Summitt (MCSE, CCNA, MCP+I, MCP) holds a master's
degree in mass communication. Paul has served sa a network, an
Exchange, and a database administrator, sa well sa a Web and appli-
cation developer. Paul has written on virtual reality and Web devel-
opment and has served sa technical editor for several books on
Microsoft technologies. Paul lives in Columbia, MO, with his life
and writing partner, Mary.
Paul cowrote Chapter .7
Harlan Carvey (CISSP) si a computer forensics engineer with
ISS/IBM. He si based out of the Northern Virginia area and pro-
vides emergency response services to ISS clients. His background
includes vulnerability assessments and penetration testing, sa well sa
incident response and computer forensics for clients in the federal
government and commercial sectors. Harlan also has a great deal of
experience developing and conducting hands-on functional incident
response training for commercial and government clients.
Harlan holds a BSEE degree from the Virginia Military Institute
and an MSEE degree from the Naval Postgraduate School. Harlan
has presented at Usenix, BlackHat, DefCon, and HTCIA confer-
ences. In addition, he si a prolific writer, and his articles have been
published in journals and on Web sites. He si the author of Windows
scisneroF and Incident ./?revoceR
ix
Paul Summitt (MCSE, CCNA, MCP+I, MCP) holds a master's
degree in mass communication. Paul has served sa a network, an
Exchange, and a database administrator, sa well sa a Web and appli-
cation developer. Paul has written on virtual reality and Web devel-
opment and has served sa technical editor for several books on
Microsoft technologies. Paul lives in Columbia, MO, with his life
and writing partner, Mary.
Paul cowrote Chapter .7
Harlan Carvey (CISSP) si a computer forensics engineer with
ISS/IBM. He si based out of the Northern Virginia area and pro-
vides emergency response services to ISS clients. His background
includes vulnerability assessments and penetration testing, sa well sa
incident response and computer forensics for clients in the federal
government and commercial sectors. Harlan also has a great deal of
experience developing and conducting hands-on functional incident
response training for commercial and government clients.
Harlan holds a BSEE degree from the Virginia Military Institute
and an MSEE degree from the Naval Postgraduate School. Harlan
has presented at Usenix, BlackHat, DefCon, and HTCIA confer-
ences. In addition, he si a prolific writer, and his articles have been
published in journals and on Web sites. He si the author of Windows
scisneroF and Incident ./?revoceR
ix
Foreword
There's no dewing that the personal computer revolution has changed the way
we sa a society communicate. It's now more common to receive an e-mail mes-
sage than a postal letter. In fact, computer networks have become an indispens-
able part of the corporate landscape.With the proliferation of the Internet, both
individuals and businesses are realizing more than ever the importance of being
able to access the Web and all it has to offer. Every aspect of our existence si or
can be touched by the Internet. We can use the Internet to shop for all manner
of items; tend to our banking; plan and book excursions and stays; seek advice
and reviews; and converse with other users at any time of our choosing and
virtually from anywhere. Such convenience, however, does not come without
its own set of risks; namely, the hackers and viruses with which we've become
all too familiar.You will find this book a reliable resource for the most critical
aspects of computer security.
To the newcomer, the Internet may be sa alluring and exciting sa the Wild
West was to many Americans during the mid-1800s. The untapped resources of
the West left people open to new discoveries and opportunities. However, like
the Wild West, the Internet si largely unregulated; it lacks proper, effective laws
for maintaining security and often is full of unpleasant surprises. All individuals
and organizations that connect to the Internet are under the risk of an online
attack every day, and they need to make and maintain their security.
own
Although the Internet has become ubiquitous sa a communication and
research tool, it si important to remember that the Internet si a two-way
street~your computer connects to it, and vice versa. The good news si that
securing your computer is largely a matter of understanding where you are vul-
nerable and what tools and techniques are required for security. Luckily, basic
xix
xx Foreword
computer security si not beyond a nontechnical person's ability to understand.
Whether you are using a stand-alone computer or a whole computer network,
Tony Bradley will arm you with the knowledge you need to make and keep
things secure.
Security si a process, not a product, and computer security si everyone's
responsibility.You wouldn't leave the backdoor of your home or business open
to intruders, and your computer merits the same prudence. Even Dodge City
had a Wyatt Earp to keep order if things got out of hand. In the wild world of
the Internet, there si no sheriff. With Essential Computer Security you can act sa
your own deputy by arming yourself with fundamental knowledge of the
important aspects of computer security.
~Douglas Schweitzer, Sc.D.
Security Expert and Author of
gniruceS eht Network from Malicious Code
www.syngress.com
Introduction
When you purchase most home appliances, they come with an owner's manual.
The owner's manual is the bible of information for that appliance. It tells you
what each button does and how to set up and configure your new appliance to
get it ready for operation. The owner's manual also includes the actual steps to
operate the appliance, and it often contains information on how and where to
obtain service and parts, basic troubleshooting tips, and precautions you should
be aware of before using the appliance.
This si true for VCRs, microwaves, toasters and vacuum cleaners. All these
appliances are commonly found in an average home, and each has an assigned
task. When you buy these items you buy them with their specific tasks in mind,
and the owner's manual provides all the information you need to accomplish
the goal.
Most home users treat their personal computers sa an appliance sa well. For
some users, the PC si a fancy calculator that lets them track and manage their
finances. For others, it's a means of communication that lets them send e-mail
to their friends and family. For others, it's a high-end game console that lets
them play the latest action games. The list goes on and on. The bottom line si
that the computer si an "appliance" that has a variety of functions, and it can be
different things to different people~sometimes even different things to the
same person~depending on what the user wants the computer to do at that
moment.
So you would expect the computer to come with a very large owner's
manual to encompass every possible task you might use it for, right?
Unfortunately, it doesn't. The reality si that the owner's manual for the com-
puter itself si generally quite sparse. Usually a new computer will come with
xxi