User Guide

Preface
xiv Dr Solomon’sAnti-Virus
The threat from virusesand other malicious softwareis real,and itis growing
worse. Some estimates have placed the total worldwide cost in time and lost
productivity for merely detecting and cleaning virus infections at more than
$10 billion per year, a figure that doesn’t include the costs of data loss and
recovery in the wake of attacks that destroyed data.
Where do viruses come from?
As you or one of your colleagues recovers from a virus attack or hears about
new forms of malicious software appearing in commonly used programs,
you’ve probably asked yourself a number of questions about how we as
computer users got to this point. Where do viruses and other malicious
programs come from? Who writes them? Why do those who write them seek
to interrupt workflows, destroy data, or cost people the time and money
necessary to eradicate them? What can stop them?
Why did this happen to me?
Itprobablydoesn’tconsoleyoumuchtohearthattheprogrammerwhowrote
the virus that erased your hard disk’s file allocation table didn’t target you or
your computer specifically. Nor will it cheer you up to learn that the virus
problemwillprobably always be withus.But knowinga bit aboutthe history
of computer viruses and how they work can help you better protect yourself
against them.
Virus prehistory
Historians have identified a number of programs that incorporated features
nowassociatedwithvirussoftware.CanadianresearcherandeducatorRobert
M. Slade traces virus lineage back to special-purpose utilities used to reclaim
unused file space and perform other useful tasks in the earliest networked
computers. Slade reports that computer scientists at a Xerox Corporation
research facility called programs like these “worms,” a term coined after the
scientists noticed “holes” in printouts from computer memory maps that
looked as though worms had eaten them. The term survives to this day to
describe programs that make copies of themselves, but without necessarily
using host software in the process.
A strong academic tradition of computer prank playing most likely
contributed to the shift away from utility programs and toward more
malicioususesoftheprogrammingtechniquesfoundinwormsoftware.
Computer science students, often to test their programming abilities, would
construct rogue worm programs and unleash them to “fight” against each
other, competing to see whoseprogram could“survive” whileshutting down
rivals. Those same students also found uses for worm programs in practical
jokes they played on unsuspecting colleagues.