Page 107 - slides.dvi

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Operating
We
e.g.
e.g.
a
it
Caller
e.g.
Called
Mutual
user
users
often
when
Systems
can
need
of
system
—
of
Virus:
Trojan
‘useful’
to
parameters)
of
should
then
starts
called
Multics
each
be
programs
Protection
user
system
self-replicating
by
off
horse:
copy
suspicion
looking
as
editor
other
user
encourage
(e.g.
should
files,
(in
be
suspicious
lots
trojan
Trojan
program
of
and
modify
—
many
horse
a
horse,
lots
ILOVEYOU,
called
files,
suspicious
of
of
game
copied
systems)
Code
change
program
files
caller
Red,
perhaps
suspicion:
as
inherits
(e.g.
all
well
OS
password,
of
Stuxnet)
as
the
calls
send
edited.
user’s
mail,
always
etc.
.
need
.
privileges
to
check
103