<s>
Foreshadow	B-Device
,	O
known	O
as	O
L1	B-Device
Terminal	I-Device
Fault	I-Device
(	O
L1TF	B-Device
)	O
by	O
Intel	O
,	O
is	O
a	O
vulnerability	O
that	O
affects	O
modern	O
microprocessors	B-Architecture
that	O
was	O
first	O
discovered	O
by	O
two	O
independent	O
teams	O
of	O
researchers	O
in	O
January	O
2018	O
,	O
but	O
was	O
first	O
disclosed	O
to	O
the	O
public	O
on	O
14	O
August	O
2018	O
.	O
</s>
<s>
The	O
vulnerability	O
is	O
a	O
speculative	B-General_Concept
execution	I-General_Concept
attack	O
on	O
Intel	B-Device
processors	I-Device
that	O
may	O
result	O
in	O
the	O
disclosure	O
of	O
sensitive	O
information	O
stored	O
in	O
personal	B-Device
computers	I-Device
and	O
third-party	B-Architecture
clouds	I-Architecture
.	O
</s>
<s>
There	O
are	O
two	O
versions	O
:	O
the	O
first	O
version	O
(	O
original/Foreshadow	O
)	O
(	O
)	O
targets	O
data	O
from	O
SGX	O
enclaves	O
;	O
and	O
the	O
second	O
version	O
(	O
next-generation/Foreshadow	O
-NG	O
)	O
(	O
)	O
targets	O
virtual	B-Architecture
machines	I-Architecture
(	O
VMs	O
)	O
,	O
hypervisors	B-Operating_System
(	O
VMM	O
)	O
,	O
operating	B-General_Concept
systems	I-General_Concept
(	O
OS	O
)	O
kernel	O
memory	O
,	O
and	O
System	B-Architecture
Management	I-Architecture
Mode	I-Architecture
(	O
SMM	O
)	O
memory	O
.	O
</s>
<s>
Foreshadow	B-Device
is	O
similar	O
to	O
the	O
Spectre	B-Error_Name
security	O
vulnerabilities	O
discovered	O
earlier	O
to	O
affect	O
Intel	O
and	O
AMD	O
chips	O
,	O
and	O
the	O
Meltdown	B-Architecture
vulnerability	I-Architecture
that	O
also	O
affected	O
Intel	O
.	O
</s>
<s>
AMD	O
products	O
are	O
not	O
affected	O
by	O
the	O
Foreshadow	B-Device
security	O
flaws	O
.	O
</s>
<s>
According	O
to	O
one	O
expert	O
,	O
"[Foreshadow]	O
lets	O
malicious	O
software	O
break	O
into	O
secure	O
areas	O
that	O
even	O
the	O
Spectre	B-Error_Name
and	O
Meltdown	B-Architecture
flaws	O
could	O
n't	O
crack	O
"	O
.	O
</s>
<s>
Nonetheless	O
,	O
one	O
of	O
the	O
variants	O
of	O
Foreshadow	B-Device
goes	O
beyond	O
Intel	O
chips	O
with	O
SGX	O
technology	O
,	O
and	O
affects	O
"	O
all	O
 [ Intel ] 	O
Core	B-Device
processors	O
built	O
over	O
the	O
last	O
seven	O
years	O
"	O
.	O
</s>
<s>
Foreshadow	B-Device
may	O
be	O
very	O
difficult	O
to	O
exploit	O
.	O
</s>
<s>
As	O
of	O
15	O
August	O
2018	O
,	O
there	O
seems	O
to	O
be	O
no	O
evidence	O
of	O
any	O
serious	O
hacking	O
involving	O
the	O
Foreshadow	B-Device
vulnerabilities	O
.	O
</s>
<s>
Companies	O
performing	O
cloud	B-Architecture
computing	I-Architecture
may	O
see	O
a	O
significant	O
decrease	O
in	O
their	O
overall	O
computing	O
power	O
;	O
people	O
should	O
not	O
likely	O
see	O
any	O
performance	O
impact	O
,	O
according	O
to	O
researchers	O
.	O
</s>
<s>
Intel	O
further	O
states	O
,	O
"	O
These	O
changes	O
begin	O
with	O
our	O
next-generation	O
Intel	B-Device
Xeon	I-Device
Scalable	I-Device
processors	I-Device
(	O
code-named	O
Cascade	B-Device
Lake	I-Device
)	O
,	O
as	O
well	O
as	O
new	O
client	O
processors	O
expected	O
to	O
launch	O
later	O
this	O
year	O
[2018].	O
 "	O
</s>
<s>
On	O
16	O
August	O
2018	O
,	O
researchers	O
presented	O
technical	O
details	O
of	O
the	O
Foreshadow	B-Device
security	O
vulnerabilities	O
in	O
a	O
seminar	O
,	O
and	O
publication	O
,	O
entitled	O
"	O
Foreshadow	B-Device
:	O
Extracting	O
the	O
Keys	O
to	O
the	O
Intel	O
SGX	O
Kingdom	O
with	O
Transient	O
Out-of-Order	O
Execution	O
"	O
at	O
a	O
USENIX	B-Operating_System
security	I-Operating_System
conference	I-Operating_System
.	O
</s>
<s>
The	O
Foreshadow	B-Device
vulnerability	O
is	O
a	O
speculative	B-General_Concept
execution	I-General_Concept
attack	O
on	O
Intel	B-Device
processors	I-Device
that	O
may	O
result	O
in	O
the	O
disclosure	O
of	O
sensitive	O
information	O
stored	O
in	O
personal	B-Device
computers	I-Device
and	O
third-party	B-Architecture
clouds	I-Architecture
.	O
</s>
<s>
There	O
are	O
two	O
versions	O
:	O
the	O
first	O
version	O
(	O
original/Foreshadow	O
)	O
(	O
[	O
attacks	O
SGX ]	O
)	O
targets	O
data	O
from	O
SGX	O
enclaves	O
;	O
and	O
the	O
second	O
version	O
(	O
next-generation/Foreshadow	O
-NG	O
)	O
(	O
[	O
attacks	O
the	O
OS	O
Kernel	O
and	O
SMM	O
mode ]	O
and	O
[	O
attacks	O
virtual	O
machines ]	O
)	O
targets	O
virtual	B-Architecture
machines	I-Architecture
(	O
VMs	O
)	O
,	O
hypervisors	B-Operating_System
(	O
VMM	O
)	O
,	O
operating	B-General_Concept
systems	I-General_Concept
(	O
OS	O
)	O
kernel	O
memory	O
,	O
and	O
System	B-Architecture
Management	I-Architecture
Mode	I-Architecture
(	O
SMM	O
)	O
memory	O
.	O
</s>
<s>
Intel	O
considers	O
the	O
entire	O
class	O
of	O
speculative	B-Error_Name
execution	I-Error_Name
side	I-Error_Name
channel	I-Error_Name
vulnerabilities	O
as	O
"	O
L1	B-Device
Terminal	I-Device
Fault	I-Device
"	O
(	O
L1TF	B-Device
)	O
.	O
</s>
<s>
For	O
Foreshadow	B-Device
,	O
the	O
sensitive	O
data	O
of	O
interest	O
is	O
the	O
encrypted	O
data	O
in	O
an	O
SGX	O
enclave	O
.	O
</s>
<s>
Usually	O
,	O
an	O
attempt	O
to	O
read	O
enclave	O
memory	O
from	O
outside	O
the	O
enclave	O
is	O
made	O
,	O
speculative	B-General_Concept
execution	I-General_Concept
is	O
permitted	O
to	O
modify	O
the	O
cache	O
based	O
on	O
the	O
data	O
that	O
was	O
read	O
,	O
and	O
then	O
the	O
processor	O
is	O
allowed	O
to	O
block	O
the	O
speculation	O
when	O
it	O
detects	O
that	O
the	O
protected-enclave	O
memory	O
is	O
involved	O
and	O
reading	O
is	O
not	O
permitted	O
.	O
</s>
<s>
Speculative	B-General_Concept
execution	I-General_Concept
can	O
use	O
sensitive	O
data	O
in	O
a	O
level	O
1	O
cache	O
before	O
the	O
processor	O
notices	O
a	O
lack	O
of	O
permission	O
.	O
</s>
<s>
The	O
Foreshadow	B-Device
attacks	O
are	O
stealthy	O
,	O
and	O
leave	O
few	O
traces	O
of	O
the	O
attack	O
event	O
afterwards	O
in	O
a	O
computer	O
's	O
logs	O
.	O
</s>
<s>
On	O
16	O
August	O
2018	O
,	O
researchers	O
presented	O
technical	O
details	O
of	O
the	O
Foreshadow	B-Device
security	O
vulnerabilities	O
in	O
a	O
seminar	O
,	O
and	O
publication	O
,	O
at	O
a	O
USENIX	B-Operating_System
security	I-Operating_System
conference	I-Operating_System
.	O
</s>
<s>
Foreshadow	B-Device
is	O
similar	O
to	O
the	O
Spectre	B-Error_Name
security	O
vulnerabilities	O
discovered	O
earlier	O
to	O
affect	O
Intel	O
and	O
AMD	O
chips	O
,	O
and	O
the	O
Meltdown	B-Architecture
vulnerability	I-Architecture
that	O
affected	O
Intel	O
.	O
</s>
<s>
AMD	O
products	O
,	O
according	O
to	O
AMD	O
,	O
are	O
not	O
affected	O
by	O
the	O
Foreshadow	B-Device
security	O
flaws	O
.	O
</s>
<s>
According	O
to	O
one	O
expert	O
,	O
"[Foreshadow]	O
lets	O
malicious	O
software	O
break	O
into	O
secure	O
areas	O
that	O
even	O
the	O
Spectre	B-Error_Name
and	O
Meltdown	B-Architecture
flaws	O
could	O
n't	O
crack	O
"	O
.	O
</s>
<s>
Nonetheless	O
,	O
one	O
of	O
the	O
variants	O
of	O
Foreshadow	B-Device
goes	O
beyond	O
Intel	O
chips	O
with	O
SGX	O
technology	O
,	O
and	O
affects	O
"	O
all	O
 [ Intel ] 	O
Core	B-Device
processors	O
built	O
over	O
the	O
last	O
seven	O
years	O
"	O
.	O
</s>
<s>
Intel	O
notes	O
that	O
the	O
Foreshadow	B-Device
flaws	O
could	O
produce	O
the	O
following	O
:	O
</s>
<s>
Malicious	O
applications	O
,	O
which	O
may	O
be	O
able	O
to	O
infer	O
data	O
in	O
the	O
operating	B-General_Concept
system	I-General_Concept
memory	O
,	O
or	O
data	O
from	O
other	O
applications	O
.	O
</s>
<s>
A	O
malicious	O
guest	O
virtual	B-Architecture
machine	I-Architecture
(	O
VM	O
)	O
may	O
infer	O
data	O
in	O
the	O
VM	O
's	O
memory	O
,	O
or	O
data	O
in	O
the	O
memory	O
of	O
other	O
guest	O
VMs	O
.	O
</s>
<s>
Foreshadow	B-Device
may	O
be	O
very	O
difficult	O
to	O
exploit	O
,	O
and	O
there	O
seems	O
to	O
be	O
no	O
evidence	O
to	O
date	O
(	O
15	O
August	O
2018	O
)	O
of	O
any	O
serious	O
hacking	O
involving	O
the	O
Foreshadow	B-Device
vulnerabilities	O
.	O
</s>
<s>
Companies	O
performing	O
cloud	B-Architecture
computing	I-Architecture
may	O
see	O
a	O
significant	O
decrease	O
in	O
their	O
overall	O
computing	O
power	O
;	O
people	O
should	O
not	O
likely	O
see	O
any	O
performance	O
impact	O
,	O
according	O
to	O
researchers	O
.	O
</s>
<s>
Intel	O
further	O
states	O
,	O
"	O
These	O
changes	O
begin	O
with	O
our	O
next-generation	O
Intel	B-Device
Xeon	I-Device
Scalable	I-Device
processors	I-Device
(	O
code-named	O
Cascade	B-Device
Lake	I-Device
)	O
,	O
as	O
well	O
as	O
new	O
client	O
processors	O
expected	O
to	O
launch	O
later	O
this	O
year	O
[2018].	O
 "	O
</s>
