<s>
Heuristic	B-Application
analysis	I-Application
is	O
a	O
method	O
employed	O
by	O
many	O
computer	O
antivirus	B-Application
programs	I-Application
designed	O
to	O
detect	O
previously	O
unknown	O
computer	O
viruses	O
,	O
as	O
well	O
as	O
new	O
variants	O
of	O
viruses	O
already	O
in	O
the	O
"	O
wild	O
"	O
.	O
</s>
<s>
Heuristic	B-Application
analysis	I-Application
is	O
an	O
expert	B-Application
based	O
analysis	O
that	O
determines	O
the	O
susceptibility	O
of	O
a	O
system	O
towards	O
particular	O
threat/risk	O
using	O
various	O
decision	O
rules	O
or	O
weighing	O
methods	O
.	O
</s>
<s>
Most	O
antivirus	B-Application
programs	I-Application
that	O
utilize	O
heuristic	B-Application
analysis	I-Application
perform	O
this	O
function	O
by	O
executing	O
the	O
programming	O
commands	O
of	O
a	O
questionable	O
program	O
or	O
script	O
within	O
a	O
specialized	O
virtual	B-Architecture
machine	I-Architecture
,	O
thereby	O
allowing	O
the	O
anti-virus	B-Application
program	I-Application
to	O
internally	O
simulate	O
what	O
would	O
happen	O
if	O
the	O
suspicious	O
file	O
were	O
to	O
be	O
executed	O
while	O
keeping	O
the	O
suspicious	O
code	O
isolated	O
from	O
the	O
real-world	O
machine	O
.	O
</s>
<s>
Another	O
common	O
method	O
of	O
heuristic	B-Application
analysis	I-Application
is	O
for	O
the	O
anti-virus	B-Application
program	I-Application
to	O
decompile	B-Application
the	O
suspicious	O
program	O
,	O
then	O
analyze	O
the	O
machine	O
code	O
contained	O
within	O
.	O
</s>
<s>
Heuristic	B-Application
analysis	I-Application
is	O
capable	O
of	O
detecting	O
many	O
previously	O
unknown	O
viruses	O
and	O
new	O
variants	O
of	O
current	O
viruses	O
.	O
</s>
<s>
However	O
,	O
heuristic	B-Application
analysis	I-Application
operates	O
on	O
the	O
basis	O
of	O
experience	O
(	O
by	O
comparing	O
the	O
suspicious	O
file	O
to	O
the	O
code	O
and	O
functions	O
of	O
known	O
viruses	O
)	O
.	O
</s>
<s>
As	O
new	O
viruses	O
are	O
discovered	O
by	O
human	O
researchers	O
,	O
information	O
about	O
them	O
is	O
added	O
to	O
the	O
heuristic	B-Application
analysis	I-Application
engine	O
,	O
thereby	O
providing	O
the	O
engine	O
the	O
means	O
to	O
detect	O
new	O
viruses	O
.	O
</s>
