Computer Viruses for Dummies

290 Pages·2004·3.582 MB·English

by  Peter H. Gregory

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Computer
Viruses
FOR
DUMmIES
‰
by Peter Gregory
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Computer
Viruses
FOR
DUMmIES
‰
by Peter Gregory
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Computer Viruses For Dummies
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Wiley Publishing, Inc.
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Copyright © 2004 by Wiley Publishing, Inc., Indianapolis, Indiana
Published by Wiley Publishing, Inc., Indianapolis, Indiana
Published simultaneously in Canada
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About the Author
Peter H. Gregory, CISA, CISSP, discovered computers in 1976
in his first year at the University of Nevada-Reno. He was taking
a FORTRAN programming course when computer programs
were painstakingly typed in on punch cards (hanging chads
and all). He then got a part-time computer operator job at the
University computer center, where he operated the university’s
mainframe computer, a Control Data Corporation CDC-6400.
His insatiable curiosity about computers led him headlong
into a career that began when he completed his university
education.
Those fancy letters behind Peter’s name: CISSP and CISA, are
two professional security certifications: Certified Information
Systems Security Professional and Certified Information
Systems Auditor. Peter has spent the past eleven years in the
wireless telecommunications industry, working in positions
where he develops security policy, security architecture, secu-
rity emergency response teams, and has been a security con-
sultant in general. His love for personal computers has kept
him attached to one or more of them for twenty years.
Author’s Acknowledgments
I would like to extend thanks to great folks at Trend Micro
(Michael Sweeny in the U.S. and Del Gemmell in Taiwan) and
Panda Software (Alan Wallace in California, Jose Javier
Merchan, and especially Fernando de la Cuadra in Spain), who
provided information as well as dozens of screen shots.
Special thanks go to Jennifer Byrne at Symantec who provided
invaluable feedback on the draft table of contents, resulting in
numerous improvements. Nalleli Lopez Hosek and David
Alderman read the entire draft manuscript and made numer-
ous productive suggestions to make the book easier to read
and understand. Thanks you two! Tim Crothers worked hard
to ensure the technical accuracy of the book.
Special thanks go to Eva Neumann, who provided invaluable
feedback from her perspective as a non-professional com-
puter user. Many thanks to my immediate and extended family
for tolerating the book writing process yet again. I’d like to
dedicate this book to the memory of Ralph Pratt who showed
me how to teach complex subjects to non-technical people.
And thanks be to God, through whom all things are possible.
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Contents at a Glance
Introduction.......................................................1
Part I: Evaluating Your Virus Situation ...............9
Chapter 1: Understanding Virus Risks ..................................................11
Chapter 2: Does My Computer Have a Virus? ......................................23
Chapter 3: DoesYour Computer HaveAntivirusSoftware?................33
Part II: Deploying Your Antivirus Defenses ........49
Chapter 4: Obtaining and Installing Antivirus Software .....................51
Chapter 5: Configuring Antivirus Software ..........................................75
Chapter 6: Scanning Your Computer and E-Mail .................................87
Chapter 7: Ridding Your Computer of Viruses ....................................99
Part III: Maintaining Your Vigilance ...............115
Chapter 8: Updating Antivirus Software and Signatures ..................117
Chapter 9: Installing Security Patches ................................................127
Chapter 10: Using Firewalls and Spyware Blockers ..........................153
Chapter 11: Protecting PDAs from Viruses ........................................181
Chapter 12: Incorporating Safe Computing Practices ......................189
Part IV: Looking at Viruses under
the Microscope ..............................................207
Chapter 13: Viruses and the Losers Who Write Them .....................209
Chapter 14: Trojan Horses, Worms, Spam, and Hoaxes ...................221
Chapter 15: How Viruses Function and Propagate ...........................235
Part V: The Part of Tens .................................247
Chapter 16: Almost Ten Myths about Computer Viruses ................249
Chapter 17: Ten Antivirus Programs ...................................................255
Index.............................................................265
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Table of Contents
Introduction .......................................................1
About This Book ........................................................................1
How This Book Is Organized .....................................................2
Part I: Evaluating Your Virus Situation ..........................2
Part II: Deploying Your Antivirus Defenses ..................2
Part III: Maintaining Your Vigilance ...............................3
Part IV: Looking at Viruses under the Microscope ......3
Part V: The Part of Tens ..................................................4
Conventions Used in This Book ...............................................4
What You’re Not to Read ...........................................................4
Meanings of the Term “Virus” ..................................................4
Foolish Assumptions .................................................................5
Icons Used in This Book ............................................................6
Where to Go from Here .............................................................7
Write to Us! .................................................................................8
Part I: Evaluating Your Virus Situation ................9
Chapter 1: Understanding Virus Risks . . . . . . . . . . . . . . 11
Assessing the Threat to Your Computer ...............................12
Which operating system are you using? .....................12
Do you install security patches? ..................................14
How many people use the computer? ........................15
How is your computer connected to the Internet? ...15
Do you have a firewall? .................................................16
High-risk activities .........................................................18
Deciding How Much Security Is Enough ...............................21
Chapter 2: Does My Computer Have a Virus? . . . . . . . . 23
Looking at Common Virus Symptoms ...................................24
Computer too slow ........................................................24
Unexplained activity ......................................................25
Crashes or hangs ...........................................................25
Will not boot ...................................................................26
Strange computer behavior ..........................................26
Too many pop-up windows ..........................................27
Finding and Fixing a Virus .......................................................28
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Computer Viruses For Dummies
Developing Good Habits .........................................................29
Keeping antivirus software up to date ........................30
Scan for viruses periodically ........................................30
Install security patches .................................................30
Working on good computer hygiene ...........................31
Blocking malicious network traffic with a firewall ....31
Blocking spyware ...........................................................31
Do you have a PDA? .......................................................32
Finding Out More about Viruses ............................................32
Chapter 3: DoesYour Computer Have
AntivirusSoftware? . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Understanding Antivirus Software .........................................34
Looking Around for Antivirus Icons ......................................35
Look in — or hunt for — the system tray ...................35
Look on the Start menu ................................................38
Look on the desktop ......................................................40
Look at installed programs ...........................................41
Asking at Your Place of Purchase ..........................................43
Checking the Health of Your Antivirus Software ..................44
Step 1: Determining whether your antivirus
software starts at bootup .........................................44
Step 2: Determining the version of antivirus
software .......................................................................46
Step 3: Figuring out when the last
update occurred ........................................................47
Step 4: Figuring out when the last scan occurred .....47
Part II: Deploying Your Antivirus Defenses ........49
Chapter 4: Obtaining and Installing
Antivirus Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Sticking with Name Brands You Know ..................................51
Considering Important Antivirus Features ...........................53
Fee or free subscription? ..............................................53
Scanning: Manual and scheduled ................................54
Compatibility with your e-mail program ....................55
Virus-definition updates ...............................................55
Fix and recovery ............................................................56
Bundling other features ................................................57
Upgrading and Switching Brands ...........................................60
Reasons to upgrade .......................................................60
Reasons to switch brands ............................................61
Upgrading or switching brands safely ........................63