The Exploit: A Theory of Networks - asounder

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computer’s normal MBR. Early antivirus programs performed a calculation
in which the size of program files was routinely checked for
any changes (unlike document files, program files should not change,
and thus a change in the file size indicated an add - on or other type of
virus). Second - generation viruses were able to outmaneuver these
calculations by either ballooning or pruning program code so that it
always remains the same size. Third - generation viruses, such as “stealth”
viruses, went further, being able to intercept and mimic the antivirus
software, thereby performing fake file scans. Fourth - generation viruses
are the opposite of the third generation; they employ “junk code”
and “attack code” to carry out multipronged infiltrations, in effect
overwhelming the computer’s antivirus software (“armored” viruses).
However, one antivirus technique has remained nominally effective,
and that is the identification of viruses based on their unique “signature,”
a string of code that is specific to each virus class. Many antivirus
programs use this approach today, but it also requires a constantly
updated record of the most current viruses and their signatures. Fifth -
generation viruses, or “polymorphic” viruses, integrate aspects of
artificial life and are able to modify themselves while they replicate and
propagate through networks. Such viruses contain a section of code—a
“mutation engine”—whose task is to continuously modify its signature
code, thereby evading or at least confusing antivirus software.
They are, arguably, examples of artificial life. 64
Viruses such as the polymorphic computer viruses are defined by their
ability to replicate their difference. They exploit the network.
That is, they are able to change themselves at the same time that
they replicate and distribute themselves. In this case, computer viruses
are defined by their ability to change their signature and yet maintain
a continuity of operations (e.g., overwriting code, infiltrating as
fake programs, etc.). Viruses are never quite the same. This is, of course,
one of the central and most disturbing aspects of biological viruses—
their ability to continuously and rapidly mutate their genetic codes.
This ability not only enables a virus to exploit new host organisms
previously unavailable to it but also enables a virus to cross species
boundaries effortlessly, often via an intermediary host organism. There