<s>
JIT	B-General_Concept
spraying	I-General_Concept
is	O
a	O
class	O
of	O
computer	O
security	O
exploit	O
that	O
circumvents	O
the	O
protection	O
of	O
address	O
space	O
layout	O
randomization	O
(	O
ASLR	O
)	O
and	O
data	O
execution	O
prevention	O
(	O
DEP	O
)	O
by	O
exploiting	O
the	O
behavior	O
of	O
just-in-time	O
compilation	O
.	O
</s>
<s>
It	O
has	O
been	O
used	O
to	O
exploit	O
the	O
PDF	B-Application
format	I-Application
and	O
Adobe	B-Operating_System
Flash	I-Operating_System
.	O
</s>
<s>
A	O
JIT	B-General_Concept
spray	I-General_Concept
attack	O
does	O
heap	O
spraying	O
with	O
the	O
generated	O
code	O
.	O
</s>
<s>
The	O
input	O
program	O
,	O
usually	O
JavaScript	B-Language
or	O
ActionScript	B-Operating_System
,	O
typically	O
contains	O
numerous	O
constant	O
values	O
that	O
can	O
be	O
erroneously	O
executed	O
as	O
code	O
.	O
</s>
<s>
JIT	O
then	O
will	O
transform	O
bytecode	O
to	O
native	O
x86	B-Operating_System
code	O
like	O
:	O
</s>
<s>
For	O
example	O
,	O
a	O
buffer	B-General_Concept
overflow	I-General_Concept
or	O
use	B-Error_Name
after	I-Error_Name
free	I-Error_Name
bug	O
could	O
allow	O
the	O
attack	O
to	O
modify	O
a	O
function	B-Language
pointer	I-Language
or	O
return	O
address	O
.	O
</s>
<s>
Computer	O
hardware	O
that	O
allows	O
jumping	O
into	O
the	O
middle	O
of	O
an	O
instruction	O
includes	O
x86	B-Operating_System
,	O
x86-64	B-Device
,	O
and	O
ARM	B-Architecture
.	O
</s>
<s>
Although	O
especially	O
effective	O
on	O
this	O
type	O
of	O
hardware	O
,	O
JIT	B-General_Concept
spraying	I-General_Concept
works	O
on	O
other	O
systems	O
as	O
well	O
.	O
</s>
<s>
To	O
protect	O
against	O
JIT	B-General_Concept
spraying	I-General_Concept
,	O
the	O
JIT	O
code	O
can	O
be	O
disabled	O
or	O
made	O
less	O
predictable	O
for	O
the	O
attacker	O
.	O
</s>
