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4
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v
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t
ac
k
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s
an
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f
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s
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i
o
n
6
c
on
s
i
s
t
s
of
pu
r
pos
e
a
n
d c
on
c
l
u
s
i
o
n
ab
o
u
t
t
h
e r
es
ear
ch
.
F
i
g
ur
e
1
.
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m
p
act
o
f
s
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r
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t
y
as
p
ect
f
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r
cl
o
u
d
2.
CL
O
UD ARCH
I
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C
T
UR
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C
l
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d
A
r
ch
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t
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r
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t
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.
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r
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E
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e.
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w
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)
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d
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ack
E
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r
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o
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f
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l
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a
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I
a
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,
P
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an
d
S
aaS
[
9
]
.
A
s
p
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C
l
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A
ll
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C
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P
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w
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[
1
0
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C
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k
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F
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2.
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i
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2
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F
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.
3.
S
E
CUR
I
T
Y I
N C
L
O
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CH
I
T
E
CT
URE
I
n
C
l
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d
A
r
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t
ect
u
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t
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act
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s
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l
v
ed
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f
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n
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g
o
f
cl
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.
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ar
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o
u
d
pr
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de
r
a
n
d c
l
ou
d u
s
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s
.
T
hus
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t
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s
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qu
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r
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d t
o de
f
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da
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pr
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a
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C
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A
l
l
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n
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e
(
C
S
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)
s
t
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k
m
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boun
da
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or
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v
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m
ode
l
[
10]
.
C
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d pr
ov
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de
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t
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.
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pon
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.
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t
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va
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l
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cc
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T
h
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s
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f
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m
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t
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r
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:
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kur
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[
11]
.
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2010
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2
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[
1
4]
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I
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2011
F
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t i
m
p
a
c
t o
n
th
r
e
e
v
e
r
y
i
m
p
o
r
ta
n
t s
e
c
u
r
i
t
y
p
a
r
a
m
e
te
r
s
c
o
n
f
id
e
n
tia
ll
y
,
in
te
g
r
it
y
a
n
d
a
v
a
ila
b
ilit
y
[
1
6
]
.
I
n
2012,
J
o
s
h
i
an
d
V
i
j
ay
a
n
c
ar
r
i
ed
o
u
t
t
h
ei
r
r
es
ear
ch
f
o
r
z
o
m
b
i
e
a
t
t
ack
p
r
ev
en
t
i
o
n
.
I
n
t
h
i
s
p
ap
er
,
C
l
o
u
d
T
r
ace
B
ack
(
C
T
B
)
m
o
d
el
w
as
s
u
g
g
es
t
ed
as
a p
r
ev
en
t
i
o
n
t
ech
n
i
q
u
e.
T
h
i
s
m
o
d
el
b
as
ed
o
n
d
et
er
m
i
n
i
s
t
i
c
p
a
c
k
e
t
m
a
r
k
i
n
g
a
l
g
o
r
ith
m
.
I
t
u
s
e
s
c
lo
u
d
p
r
o
te
c
to
r
c
o
n
s
i
s
t o
f
v
ir
tu
a
l
f
ir
e
w
a
ll to
v
e
r
i
f
y
th
e
r
e
q
u
e
s
t a
u
th
e
n
tic
it
y
o
f
ge
nu
i
n
e
u
s
er
w
i
t
h
h
e
l
p
o
f
w
h
i
t
e a
n
d
b
l
ack
I
P
ad
d
r
es
s
l
i
s
t
[
1
7
]
.
I
n
s
a
m
e
y
ear
D
u
a
n
,
C
h
en
,
S
an
c
h
ez,
D
o
n
g
al
s
o
car
r
i
ed
o
u
t
t
h
ei
r
r
es
ear
ch
i
n
f
i
el
d
o
f
zo
m
b
i
e at
t
ack
.
T
h
i
s
p
ap
er
i
n
t
r
o
d
u
ced
a S
P
O
T
ap
p
r
o
ach
t
o
d
et
ect
t
h
e
c
o
m
p
r
o
m
i
s
e
vi
r
t
ua
l
m
a
c
hi
ne
b
y
m
o
ni
t
o
r
i
n
g o
ut
go
i
n
g
m
e
s
s
a
g
e
.
I
t is
b
a
s
e
d
o
n
a
p
o
w
e
r
f
u
l s
ta
tis
tic
to
o
l
S
e
qu
e
n
t
i
a
l
P
r
oba
bi
l
i
t
y
R
a
t
i
o
T
e
s
t
(
S
P
R
T
)
.
T
h
i
s
S
P
O
T
a
pp
r
oa
c
h
de
pe
n
d
u
pon
t
w
o
i
m
por
t
a
n
t
t
e
r
m
i
n
ol
og
i
e
s
co
u
n
t
t
h
r
es
h
o
l
d
an
d
p
er
cen
t
ag
e t
h
r
es
h
o
l
d
t
o
d
et
ect
t
h
e
m
al
i
c
i
o
u
s
s
p
a
m
m
e
s
s
a
g
e f
r
o
m
i
n
t
er
n
al
m
ac
h
i
n
e [
18]
.
I
n
2013,
K
e
i
k
o,
D
a
v
i
d,
E
du
a
r
do c
on
du
c
t
e
d t
h
e
i
r
r
e
s
e
a
r
c
h
on
t
h
r
e
a
t
s
i
n
c
l
u
di
ng
a
c
c
oun
t
c
on
t
r
ol
,
m
a
lic
io
u
s
i
n
te
r
n
a
l s
ta
f
f
,
m
u
lt
i
-
t
e
n
an
t
p
r
o
b
l
em
,
d
at
a co
n
t
r
o
l
an
d
s
af
e
t
y
m
a
n
ag
e
m
e
n
t
.
T
h
e p
u
r
p
o
s
e
w
as
t
o
hi
g
hl
i
g
ht
l
a
c
k
i
n
g i
n e
xi
s
t
i
n
g s
ys
t
e
m
.
I
n t
he
e
nd
c
o
unt
er
m
e
as
u
r
es
ar
e al
s
o
d
i
s
cu
s
s
ed
t
o
r
ed
u
ce o
r
o
v
er
co
m
e
t
he
e
f
f
e
c
t
o
f
t
he
s
e
t
hr
e
a
t
s
[
1
9
]
.
I
n s
a
m
e
ye
a
r
,
C
h
i
r
a
g,
D
hi
r
e
n,
B
ha
ve
s
h,
A
vi
,
M
ut
t
ukr
i
s
h
n
a
n t
o
o
k o
ne
f
ur
t
he
r
s
t
ep
i
n
an
al
y
s
i
n
g
v
u
l
n
er
ab
i
l
i
t
i
es
,
at
t
ack
s
an
d
t
h
ei
r
co
r
r
es
p
o
n
d
i
n
g
t
h
r
eat
s
.
T
h
e p
u
r
p
o
s
e w
a
s
t
o
g
en
er
at
e a
l
i
n
k
i
n
g
b
et
w
een
t
h
e
v
u
l
n
er
ab
i
l
i
t
i
es
,
at
t
ack
s
a
n
d
t
h
r
eat
s
[
2
0
]
.
I
n
s
a
m
e
y
ear
J
y
o
t
i
,
R
i
t
u
,
N
e
h
a,
Mo
n
i
k
a
car
r
i
ed
o
ut
t
he
i
r
r
e
s
e
a
r
c
h o
n
p
hi
s
hi
n
g a
t
t
a
c
k.
T
hi
s
p
a
p
e
r
t
hr
o
w
n
l
i
gh
t
o
n
va
r
i
o
us
w
a
ys
m
e
a
ns
t
o
p
l
a
n a
p
hi
s
hi
n
g
a
t
t
a
c
k s
uc
h a
s
s
e
nd
i
n
g b
ul
k
m
a
i
l
s
o
r
b
y
cr
eat
i
n
g
a
w
eb
p
ag
e s
i
m
i
l
ar
t
o
w
el
l
-
k
n
o
w
n
w
eb
s
i
t
es
et
c.
I
n
t
h
e en
d
i
nt
r
o
d
uc
e
d
a
nt
i
-
p
hi
s
hi
ng t
e
c
h
ni
q
ue
s
s
uc
h a
s
s
e
r
ve
r
b
a
s
e
d
t
e
c
hni
q
ue
w
i
t
h
he
l
p
o
f
b
r
a
nd
m
o
ni
t
o
r
i
n
g,
b
e
ha
v
i
o
ur
d
et
ect
i
o
n
,
s
ecu
r
i
t
y
i
n
ci
d
e
n
ces
&
cl
i
en
t
b
as
ed
t
ech
n
i
q
u
e i
n
cl
u
d
i
n
g
e
m
a
i
l
a
n
a
l
y
s
i
s
,
b
la
c
k
lis
t,
s
i
m
ila
r
it
y
o
f
la
y
o
u
t e
tc
.
[
2
1
]
.
I
n
2015,
T
o
r
k
u
r
a,
C
h
en
g
,
M
ei
n
el
co
n
d
u
ct
ed
t
h
ei
r
r
es
ear
ch
i
n
d
ev
el
o
p
m
e
n
t
p
r
o
act
i
v
e
v
u
l
n
er
ab
i
l
i
t
y
as
s
es
s
m
en
t
f
r
a
m
e
w
o
r
k
.
V
ar
i
o
u
s
s
ca
n
n
er
s
ar
e d
ep
l
o
y
ed
f
o
r
ear
l
y
d
et
ect
i
o
n
o
f
t
h
es
e
f
l
a
w
s
i
n
cl
o
u
d
ar
ch
i
t
ect
u
r
e.
I
n
t
h
i
s
p
ap
er
,
a q
u
an
t
i
t
at
i
v
e
r
i
s
k
as
s
es
s
m
e
n
t
w
a
s
co
n
d
u
c
t
ed
o
v
er
o
p
en
s
t
ack
v
u
l
n
er
ab
i
l
i
t
y
l
i
f
e c
y
cl
e an
d
n
o
t
i
ced
d
i
f
f
er
en
t
r
i
s
k
l
e
v
el
d
u
e t
o
p
r
o
l
o
n
g
ed
p
at
ch
r
el
eas
e an
d
i
n
cl
u
s
i
o
n
d
u
r
at
i
o
n
.
T
h
es
e r
i
s
k
l
e
v
el
ar
e b
l
ac
k
r
i
s
k,
gr
e
y r
i
s
k a
nd
w
h
i
t
e
r
i
s
k.
E
xi
s
t
i
ng
s
c
a
nn
e
r
s
a
r
e
w
or
k
i
ng t
o
m
i
t
i
g
a
t
e
w
hi
t
e
r
i
s
k
o
n
l
y
w
i
t
h
t
h
e
h
e
l
p o
f
ope
n
s
o
u
r
ce
v
u
l
n
er
ab
i
l
i
t
y
d
at
ab
as
e
(
O
S
V
D
B
)
an
d
N
at
i
o
n
al
v
u
l
n
e
r
ab
i
l
i
t
y
d
at
ab
as
e (
N
V
D
)
.
T
h
i
s
p
ap
er
p
r
o
p
o
s
ed
a
p
r
o
a
c
tiv
e
f
r
a
m
e
w
o
r
k
f
o
r
v
u
l
n
e
r
a
b
ilit
y
a
s
s
e
s
s
m
e
n
t to
m
iti
g
a
t
e
th
e
r
is
k
le
v
e
l
s
i
n gr
e
y a
nd
b
l
a
c
k l
e
ve
l
w
i
t
h he
l
p
o
f
i
nc
l
ud
i
n
g
m
o
r
e
d
y
na
m
i
c
s
o
ur
c
e
s
s
uc
h a
s
B
u
g T
r
a
c
ki
ng S
ys
t
e
m
(
B
T
S
)
,
m
a
l
i
c
i
o
u
s
s
i
gna
t
ur
e
r
e
p
o
s
i
t
o
r
y
a
n
d
e
x
pl
oi
t
e
d da
t
a
ba
s
e
(
E
D
B
)
[
22]
.
I
n
s
a
m
e
y
ear
M
as
k
y
,
Y
o
u
n
g
,
C
h
o
e p
r
o
p
o
s
ed
O
p
er
at
i
o
n
al
l
y
C
r
i
t
i
cal
T
h
r
eat
s
A
s
s
e
t
V
u
l
n
er
ab
i
lit
y
E
v
a
lu
a
tio
n
(
O
C
T
A
V
E
)
a
s
a
n
o
v
e
l r
i
s
k
id
e
n
ti
f
ic
a
t
io
n
f
r
a
m
e
w
o
r
k
f
o
r
s
e
c
u
r
it
y
is
s
u
e
s
.
I
t
w
a
s
n
o
tic
e
d
th
a
t
o
ccu
r
r
en
ce o
f
v
ar
i
o
u
s
t
h
r
eat
s
i
s
d
u
e t
o
i
m
p
r
o
p
er
i
d
en
t
i
f
i
ca
t
i
o
n
a
n
d
i
m
p
act
a
s
s
e
s
s
m
e
n
t
o
f
r
i
s
k
o
v
er
cl
o
u
d
.
T
h
i
s
pr
op
os
e
d f
r
a
m
e
w
or
k
pe
r
f
or
m
e
d t
h
e
w
or
k
i
ng
i
n
f
ou
r
ph
a
s
e
s
c
ons
i
s
t
of
e
i
gh
t
s
t
e
ps
.
F
i
r
s
t
ph
a
s
e
i
s
a
bou
t
t
o
d
ev
el
o
p
a r
i
s
k
m
eas
u
r
e
m
en
t
c
r
i
t
er
i
a ar
o
u
n
d
q
u
al
i
t
a
t
i
v
e p
ar
a
m
et
er
s
u
c
h
as
R
ep
u
t
at
i
o
n
/
C
o
n
f
i
d
en
ce,
F
i
n
a
n
ci
al
R
e
q
ui
r
e
m
e
nt
,
P
r
o
d
uc
t
i
vi
t
y
,
S
a
f
e
t
y
a
nd
H
e
a
l
t
h,
F
i
ne
a
nd
le
g
a
l p
e
n
a
ltie
s
w
it
h
p
r
io
r
i
t
y
w
i
s
e
r
a
nki
n
g.
I
n p
ha
s
e
2
a
ll th
e
i
n
f
o
r
m
a
tio
n
a
s
s
e
t t
h
a
t a
r
e
id
e
n
tif
ie
d
to
b
e
c
r
itic
a
l a
r
e
p
r
o
f
ile
d
.
T
h
is
p
r
o
f
ili
n
g
i
n
c
l
u
d
e
s
th
e
id
e
n
ti
f
ic
a
tio
n
o
f
s
ecu
r
i
t
y
r
eq
u
i
r
e
m
e
n
t
o
f
i
n
f
o
r
m
at
i
o
n
as
s
et
a
n
d
al
s
o
i
d
en
t
i
f
i
es
t
h
e co
n
t
ai
n
er
w
h
er
e i
t
i
s
s
t
o
r
ed
,
t
r
an
s
p
o
r
t
ed
an
d
p
r
o
ces
s
ed
.
P
h
as
e 3
i
s
ab
o
u
t
t
o
i
d
en
t
i
f
y
t
h
e t
h
r
eat
s
t
o
i
n
f
o
r
m
at
i
o
n
a
s
s
et
.
I
n
f
i
n
al
p
h
as
e
i
d
en
t
i
f
y
t
h
e
r
i
s
k
t
o
t
h
e i
n
f
o
r
m
a
t
i
o
n
as
s
et
.
T
h
i
s
r
i
s
k
m
a
y
b
e v
i
e
w
ed
as
co
m
b
i
n
at
i
o
n
o
f
t
h
r
eat
s
w
i
t
h
t
h
ei
r
ad
v
er
s
e i
m
p
act
o
v
er
t
h
e
s
ys
t
e
m
.
F
i
na
l
l
y
i
nc
l
ud
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5
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5.
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W
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i
s
i
t
s
t
o
m
al
i
ci
o
u
s
w
eb
s
i
t
e a
n
d
p
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o
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e
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P
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k
acc
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s
cr
ed
en
t
i
al
,
p
o
o
r
a
u
th
o
r
iz
a
tio
n
a
nd
in
p
u
t
v
a
lid
a
tio
n
te
c
h
n
iq
u
e
s
[
1
9
]
ar
e v
u
l
n
e
r
ab
l
e t
o
m
al
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ci
o
u
s
act
i
v
i
t
i
es
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u
ch
P
h
i
s
h
i
n
g
at
t
ac
k
[
2
1
]
,
an
d
S
er
v
i
ce I
n
j
ect
i
o
n
at
t
ack
[
2
6
-
28]
.
5.
1.
6.
D
at
a
S
t
or
age
R
e
l
at
e
d
V
u
l
n
e
r
ab
i
l
i
t
i
e
s
D
at
a o
f
m
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l
t
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p
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en
a
n
t
s
ar
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t
o
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ed
at
s
a
m
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o
cat
i
o
n
.
S
u
c
h
s
t
o
r
ag
e
m
a
y
a
s
k q
ue
s
t
i
o
ns
o
n r
o
b
us
t
ne
s
s
o
f
s
e
g
r
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g
a
tio
n
a
n
d
i
s
o
la
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m
e
c
h
a
n
i
s
m
f
o
r
d
a
ta
o
f
m
u
ltip
le
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n
a
n
ts
w
h
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h
w
a
s
s
to
r
e
d
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n
d
e
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d
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f
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j
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d
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i
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n
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o
r
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t
al
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o
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h
e p
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o
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o
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n
co
m
p
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r
e d
at
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el
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,
t
r
a
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p
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y
[1
9
],
an
d
m
et
a
-
d
at
a
s
poof
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n
g
a
t
t
a
c
k
[
20]
.
5
.2
.
C
la
s
s
if
ic
a
t
io
n
o
f
A
tta
c
k
s
A
tta
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k
m
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y
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d
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f
in
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d
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s
w
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lo
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l
n
e
r
a
b
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s
to
h
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r
m
t
h
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y
s
te
m
.
D
i
f
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e
n
t t
y
p
e
s
o
f
at
t
ack
ar
e l
i
s
t
ed
as
:
5.
2.
1.
Z
o
m
b
i
e
A
t
t
ac
k
A
n
at
t
ack
er
co
m
p
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s
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o
s
t
t
o
p
l
an
a Z
o
m
b
i
e at
t
ac
k
[
2
0
]
.
T
h
es
e h
o
s
t
s
ar
e u
s
ed
b
y
h
ack
er
t
o
s
en
d
l
ar
g
e n
u
m
b
er
o
f
r
eq
u
e
s
t
f
o
r
a v
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r
t
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al
m
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i
n
e.
T
h
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s
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u
p
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p
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b
eh
av
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f
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b
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D
en
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al
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f
S
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(
D
D
o
S
)
[
1
7
]
.
T
h
i
s
m
a
y
b
e p
r
ev
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t
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v
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a a
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19 h
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C
l
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I
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r
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[3
2
].
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In
t
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5
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2
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2
.
S
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i
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A
t
t
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a m
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r
cr
eat
e
a n
e
w
v
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r
t
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al
m
ac
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e [
2
0
]
.
I
f
at
t
ack
er
s
u
cceed
s
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o
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g
s
o
,
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T
h
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it
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5.
2.
3.
A
t
t
ac
k
on
V
i
r
t
u
al
i
z
at
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on
VM
E
s
cap
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A
m
a
l
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ci
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s
p
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m
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n
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act
w
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H
y
p
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s
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hi
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O
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c
on
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h
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[
20]
.
5
.2
.4
.
M
an
-
in
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t
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-
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A
t
t
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M
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.
[
2
0
]
.
5.
2.
5.
A
R
P
S
p
oof
i
n
g
A
t
t
ac
k
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n
d
s
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f
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A
R
P
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o
co
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ect
I
P
ad
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s
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it
h
a
m
a
lic
io
u
s
h
o
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t.
T
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A
R
P
doe
s
n
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r
e
qu
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pr
oof
of
or
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f
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s
ou
r
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e
.
T
h
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s
f
l
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w
m
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t
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s
to
m
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r
to
a
m
a
lic
io
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s
h
o
s
t [
2
0
]
.
5.
2.
6.
D
N
S
P
oi
s
on
i
n
g
D
N
S
s
er
v
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s
p
r
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d
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ap
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b
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w
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h
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o
m
a
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n
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m
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t
o
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p
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P
ad
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t
h
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p
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t
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d
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m
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n
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es
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l
v
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cach
e.
I
f
ca
ch
e co
n
s
i
s
t
s
o
f
a co
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r
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p
t
d
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m
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w
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c
u
s
to
m
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to
a
m
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s
w
e
b
s
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te
.
T
h
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is
d
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la
w
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D
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w
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a
lid
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m
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c
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ni
s
m
[
2
0
]
5.
2.
7.
M
e
t
a D
at
a
S
p
oof
i
n
g A
t
t
ac
k
P
r
es
en
ce o
f
w
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k
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u
t
h
en
t
i
c
at
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n
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au
t
h
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m
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h
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n
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s
m
,
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n
d
m
al
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ci
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s
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er
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al
s
t
af
f
w
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t
h
o
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t
d
at
ed
en
cr
y
p
t
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o
n
t
ec
h
n
i
q
u
e al
l
o
w
s
a
n
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t
ac
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o
ch
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e o
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m
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d
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f
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t
h
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f
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m
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ab
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t
h
e s
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s
st
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d
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n
w
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s
er
v
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cr
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p
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l
a
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g
e (
W
S
D
L
)
f
i
l
e at
d
el
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v
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t
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m
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I
t
h
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p
s
t
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t
a
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t
o
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a
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n
acce
s
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r
v
a
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s
i
m
por
t
a
n
t
a
ppl
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c
a
t
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on
or
s
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n
s
i
t
i
v
e
i
nf
or
m
a
t
i
o
n
[
20]
.
5.
2.
8.
P
h
i
s
h
i
n
g A
t
t
ac
k
A
n
a
tta
c
k
e
r
m
a
y
u
s
e
th
e
w
e
b
s
e
r
v
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e
s
to
m
a
n
ip
u
la
te
th
e
lin
k
an
d
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t
h
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t
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s
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hi
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g
A
t
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a
c
k [
2
0
]
.
5.
3.
C
l
as
s
i
f
i
c
at
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on
of
T
h
r
e
at
s
T
h
r
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s
can
b
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n
d
er
s
t
a
n
d
as
f
i
n
al
p
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t
en
t
i
al
l
o
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s
f
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t
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e s
y
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t
e
m
.
T
h
e
y
can
b
e l
i
s
t
ed
as
:
5
.
3
.
1
.
L
o
s
s
co
n
t
ro
l
o
v
er R
es
o
u
rces
I
n c
l
o
ud
a
r
c
h
i
t
e
c
t
ur
e
,
o
r
ga
ni
z
a
t
i
o
ns
ha
nd
e
d
o
ve
r
t
he
i
r
s
e
ns
i
t
i
ve
b
u
s
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ne
s
s
a
p
p
l
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c
a
tio
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a
n
d
in
f
o
r
m
a
tio
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t
o t
h
i
r
d pa
r
t
y
v
e
n
dor
.
A
s
a
m
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t
t
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r
of
pol
i
c
y
,
c
l
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d pr
ov
i
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doe
s
n
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pr
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de
t
r
a
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s
pa
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c
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bou
t
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p
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e.
h
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an
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H
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s
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s
[
24]
.
T
h
u
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or
g
a
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on
m
a
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o
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p
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eq
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f
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r
c
o
n
tr
o
l in
S
er
vi
ce L
evel
A
g
r
eem
en
t
.
5.
3.
2.
M
i
s
u
s
e
of
c
l
ou
d
c
o
m
p
u
t
i
n
g
res
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P
r
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m
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a
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d
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t
a
t
t
a
c
ks
ov
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r
c
l
ou
d c
om
pu
t
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ng
[
24]
.
I
t
s
h
ou
l
d be
a
v
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d v
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m
pl
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m
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r
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k up
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th
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n
tic
a
tio
n
te
c
h
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iq
u
e
s
.
Evaluation Warning : The document was created with Spire.PDF for Python.
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5.
3.
3.
M
al
i
c
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ou
s
I
n
s
i
d
e
r
s
W
i
t
h
h
i
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e
v
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o
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acce
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s
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an
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n
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.
I
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act
i
v
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n
b
y
p
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ed
b
y
a
f
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r
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w
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l
o
r
I
n
tr
u
s
io
n
D
e
te
c
tio
n
S
y
s
te
m
(ID
S
)
a
s
s
u
m
in
g
a
s
le
g
a
l
act
i
v
i
t
y
.
H
o
w
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v
er
,
a t
r
u
s
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n
s
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m
a
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e t
u
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n
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ar
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g
.
m
al
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ci
o
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s
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n
s
i
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m
a
y
acce
s
s
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on
f
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de
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l
da
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a
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n
d g
a
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on
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ol
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t
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e
s
w
i
t
h
n
o r
i
s
k
of
de
t
e
c
t
i
o
n
[
20]
.
C
l
ou
d pr
ov
i
de
r
s
ho
u
l
d
ha
ve
a
m
e
c
ha
ni
s
m
t
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n t
he
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m
p
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l
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v
el
o
f
acces
s
t
o
r
ead
m
a
lic
io
u
s
a
c
tio
n
.
5
.
3
.
4
.
A
cco
u
n
t
o
r S
erv
i
ce H
i
j
a
ck
i
n
g
o
r
I
de
nt
i
t
y
T
he
f
t
A
n
acco
u
n
t
o
r
s
er
v
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ce
h
i
j
ack
i
n
g
o
r
i
d
en
t
i
t
y
t
h
e
f
t
can
b
e d
ef
i
n
ed
as
h
ac
k
i
n
g
o
f
an
acco
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n
t
o
r
s
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v
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ce.
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t
m
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don
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an
s
act
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n
[
1
0
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1
9
,
an
d
2
0
]
.
T
h
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b
r
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x
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o
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s
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f
t
w
ar
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n
er
ab
i
l
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t
i
es
,
r
eu
s
ed
cr
ed
en
t
i
al
s
[
2
1
]
.
5.
3.
5.
D
at
a
S
c
ave
n
gi
n
g
D
a
t
a
f
or
m
u
l
t
i
pl
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us
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s
a
r
e
s
t
or
e
d a
t
s
a
m
e
l
oc
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t
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on i
n
c
l
oud.
I
t
i
s
pos
s
i
bl
e
da
t
a
f
or
m
u
l
t
i
pl
e
us
e
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s
m
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y
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e s
t
o
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at
s
a
m
e
d
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s
k
s
p
ace o
r
m
u
l
t
i
p
l
e co
p
i
es
o
f
d
at
a
w
er
e cr
eat
ed
t
o
e
n
s
u
r
e
h
ig
h
r
e
l
ia
b
ilit
y
a
n
d
i
n
cr
eas
e t
r
u
s
t
o
v
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cl
o
u
d
.
T
h
i
s
w
o
u
l
d
cr
eat
e p
r
o
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m
f
o
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a
p
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tic
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la
r
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g
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iz
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[
1
9
]
.
I
t is
r
e
c
o
m
m
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n
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v
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.
5.
3.
6.
D
at
a
L
os
s
or
L
e
a
k
age
D
at
a
i
n
cl
o
u
d
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s
s
h
ar
ed
a
m
o
n
g
m
u
l
t
i
p
l
e
o
r
g
an
i
zat
i
o
n
s
.
H
en
ce m
a
y
b
e
i
n
d
an
g
er
o
f
h
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s
l
e
ak
ag
e
o
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l
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s
s
.
I
t
w
a
s
l
ea
k
ed
w
h
e
n
t
r
an
s
f
er
r
ed
o
v
er
i
n
t
er
n
et
(
b
ecau
s
e
o
f
at
t
ac
k
s
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c
h
a
s
m
a
n
-
in
-
t
he
-
m
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d
le
a
tta
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k
,
A
R
P
S
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f
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)
,
p
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s
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m
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s
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d
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n
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s
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t
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eco
v
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y
p
r
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v
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d
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b
y
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r
el
i
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e p
ar
t
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,
w
e
a
k e
nc
r
yp
t
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n a
l
go
r
i
t
h
m
).
I
t s
h
o
u
ld
r
e
q
u
ir
e
ti
m
e
l
y
a
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d
it o
f
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m
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n
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,
v
a
lid
a
tio
n
a
n
d
t
e
s
t
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n
g
[
19,
20]
.
5.
3.
7.
D
e
n
i
al
of
S
e
r
vi
c
e
D
en
i
al
o
f
s
er
v
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ce
m
a
k
es
a s
i
g
n
i
f
i
can
t
i
m
p
act
o
n
s
er
v
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ce
av
ai
l
ab
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l
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t
y
m
et
r
i
cs
.
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t
w
as
cau
s
ed
b
y
r
e
c
e
i
v
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ng
l
a
r
g
e
num
be
r
of
r
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qu
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t
f
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o
m
m
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l
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c
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ous
h
os
t
.
S
u
c
h
t
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pe
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c
a
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s
e
i
s
don
e
v
i
a
Z
o
m
bi
e
a
t
t
a
c
k
[
19,
20]
.
5.
3.
8.
C
u
s
t
o
m
e
r
D
at
a M
an
i
p
u
l
at
i
on
U
s
er
at
t
ack
w
e
b
a
p
p
lic
a
tio
n
s
b
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m
a
n
ip
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la
t
in
g
d
a
ta
s
e
n
t
f
r
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m
a
p
p
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tio
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c
o
m
p
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n
e
n
t to
th
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s
e
r
v
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’
s
ap
p
l
i
cat
i
o
n
w
i
t
h
h
el
p
o
f
S
Q
L
I
n
j
ect
i
o
n
,
i
n
s
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u
r
e d
i
r
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o
b
j
e
ct
r
ef
er
en
ces
an
d
cr
o
s
s
s
i
t
e s
c
r
i
p
t
i
n
g
[
1
9
,
2
6
-
28]
.
F
i
g
ur
e
3
s
h
o
wn
m
ap
p
i
n
g
b
et
w
een
v
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l
n
er
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2.
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In
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1]
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put
e
r
a
ppl
i
c
a
t
i
ons
,
v
o
l
.
3
4,
no
.
1,
2
01
1,
pp.
1
-
11.
[
1
7]
B
.
J
os
hi
,
A
.
V
i
j
a
y
a
n,
“
S
e
c
ur
i
ng
c
l
oud c
om
put
i
ng
e
nv
i
r
o
nm
e
nt
a
g
a
i
ns
t
D
D
oS
a
t
t
a
c
k
s
”
,
I
n pr
oc
e
e
di
ng
of
I
E
E
E
I
nt
e
r
na
t
i
o
na
l
c
o
nf
e
r
e
nc
e
of
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o
m
put
e
r
c
om
m
uni
c
a
t
i
on a
nd i
nf
or
m
a
t
i
c
s
,
20
12.
[
1
8]
Z
.D
u
a
n
, P
.C
h
e
n
,
F
.S
a
n
c
he
z
,
Y
.
D
ong
,
M
.
S
t
e
phe
ns
on,
a
n
d J
.
B
a
r
k
e
r
,
“
D
e
t
e
c
t
i
ng
s
pa
m
z
o
m
bi
e
s
by
m
oni
t
or
i
ng
out
g
oi
ng
m
e
s
s
a
ge
s
”
,
I
E
E
E
t
r
a
ns
a
c
t
i
on
de
pe
n
da
bl
e
a
n
d s
e
c
ur
e
c
om
put
i
ng
,
v
ol
.
9,
no
.
2,
2
01
2,
pp.
1
98
-
2
10
[
1
9]
K
.
H
as
h
i
zu
m
e,
D
.
G
.
R
o
s
ad
o
,
E
.
F
.
M
ed
i
n
a,
E
.
B
.
F
ar
n
an
d
ez ,
“A
n
an
al
y
s
i
s
o
f
s
e
c
ur
i
t
y
i
s
s
ue
s
f
or
c
l
oud
c
om
put
i
ng
”
,
I
E
E
E
, v
o
l
.
, 2
0
1
3
[
2
0]
C
.
M
o
d
i
,
D
.
P
at
el
,
B
.
B
o
r
i
s
an
i
y
a,
A
.
P
at
el
,
M
.
R
aj
ar
aj
an
,
“A
s
u
r
v
e
y
o
n
s
ecu
r
i
t
y
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s
s
u
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an
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f
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t
l
a
y
e
r
s
of
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l
oud c
om
put
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ng
”
,
I
E
E
E
,
v
ol
.
63,
2
01
3,
pp.
5
61
-
5
92
[
2
1]
J
. C
h
h
i
k
a
r
a
, R
. D
a
h
i
y
a
, N
. G
a
r
g
,
M
.
R
a
ni
,
“
P
hi
s
hi
ng
&
A
nt
i
P
hi
s
hi
ng
T
e
c
hni
que
:
C
a
s
e
S
t
udy
”
,
I
nt
e
r
na
t
i
ona
l
J
our
na
l
of
A
dv
a
nc
e
d R
e
s
e
a
r
c
h i
n
c
om
put
e
r
s
c
i
e
nc
e
a
nd s
of
t
w
a
r
e
e
ng
i
ne
e
r
i
ng
,
v
ol
.
3
,
n
o.
5,
20
13
,
p
p.
458
-
4
65.
[
2
2]
K
.
A
.
T
or
k
ur
a
,
F
.
C
he
ng
,
C
.
M
e
i
ne
l
,
“
A
P
r
opos
e
d F
r
a
m
e
w
or
k
f
or
P
r
oa
c
t
i
v
e
V
u
ln
e
r
a
b
il
ity
A
s
s
e
s
s
m
e
n
t in
C
lo
u
d
D
e
pl
oy
m
e
nt
”
,
t
he
10
th
I
nt
e
r
na
t
i
on
a
l
C
onf
e
r
e
nc
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f
or
I
nt
e
r
ne
t
T
e
c
hno
l
og
y
a
nd S
e
c
ur
e
d T
r
a
ns
a
c
t
i
ons
,
2
015
[
2
3]
M
.
M
a
s
ky
,
S
.
S
.
Y
ou
ng
,
T
.
Y
.
C
ho
e
,
“
A
N
ov
e
l
R
i
s
k
I
de
nt
i
f
i
c
a
t
i
on F
r
a
m
e
w
or
k
f
or
C
l
oud C
om
put
i
ng
S
e
c
ur
i
t
y
”
,
I
E
E
E
T
r
an
s
act
i
o
n
,
20
15
.
[
2
4]
D
.
N
iu
,
L
.
L
iu
,
X
.
Z
.
Zh
a
n
g
,
S
.
L
ii,
Z.
L
i,
“
S
e
c
u
r
ity
A
n
a
l
y
s
is
M
o
d
e
l,
S
y
s
te
m
A
r
c
h
ite
c
tu
r
e
a
n
d
R
e
la
tio
n
a
l M
o
d
e
l
o
f
C
l
o
u
d
S
e
r
v
i
c
e
s
”
,
I
E
E
E
, V
o
l
. 1
3
,
2
0
1
6
,p
p
.5
7
4
-
5
84
[
2
5]
R
ak
s
h
i
t
a C
M
,
“Z
o
m
b
i
e at
t
ack
d
et
ect
i
o
n
an
d
co
u
n
t
er
m
eas
u
r
e
s
el
ect
i
o
n
i
n
cl
o
u
d
en
v
i
r
o
n
m
en
t
”,
I
n
t
er
n
at
i
o
n
al
J
our
na
l
of
a
dv
a
nc
e
s
i
n e
l
e
c
t
r
i
c
a
l
pow
e
r
s
y
s
t
e
m
a
nd i
nf
or
m
a
t
i
on t
e
c
hnol
og
y
,
v
ol
.
2,
n
o.
4,
20
16,
p
p.
24
-
28.
[
2
6]
B
.
I
n
d
r
a
n
i
,
E
.
R
am
ar
aj
,
“
A
n
A
p
p
r
o
ach
t
o
d
et
ect
an
d
p
r
ev
en
t
S
Q
L
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n
j
ect
i
o
n
A
t
t
ack
s
i
n
d
at
ab
as
e u
s
i
n
g
w
eb
s
er
v
i
ce
s
”,
I
n
te
r
n
a
tio
n
a
l J
o
u
r
na
l
of
c
om
put
e
r
s
c
i
e
nc
e
a
nd ne
t
w
or
k
s
e
c
ur
i
t
y
,
v
ol
.
11,
2
01
1,
pp.
1
97
-
2
05
[
2
7]
B
.
I
n
d
r
an
i
,
E
.
R
am
ar
aj
,
“P
r
ev
en
t
i
o
n
o
f
S
Q
L
I
n
j
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i
o
n
at
t
ack
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y
u
s
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n
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er
v
i
ce o
r
i
en
t
ed
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t
h
en
t
i
cat
i
o
n
t
ech
n
i
q
u
e”
,
I
nt
e
r
na
t
i
o
na
l
J
o
ur
na
l
of
m
ode
l
i
ng
a
nd opt
i
m
i
z
a
t
i
on,
v
ol
.
3,
no.
3,
20
13
,
p
p.
30
2
-
3
06
[
2
8]
R
.
S
h
r
i
v
as
t
av
a,
J
.
B
h
at
t
ach
ar
y
j
i
,
R
.
S
o
n
i
,
“S
Q
L
I
n
j
ect
i
o
n
A
t
t
ac
k
s
i
n
D
at
ab
as
e
u
s
i
n
g
w
eb
s
er
v
i
c
es
:
D
et
ect
i
o
n
an
d
pr
e
v
e
nt
i
on
-
R
e
v
i
e
w
”
,
A
s
i
a
n J
our
na
l
of
c
om
put
e
r
s
c
i
e
nc
e
a
nd i
nf
or
m
a
t
i
on t
e
c
h
nol
og
y
,
v
ol
.
2,
n
o.
6
,
201
2,
p
p.
16
2
-
165
[
2
9]
K
i
ng
S
,
C
he
n P
,
W
a
n
g
Y
M
,
“
S
u
b
v
e
r
t: im
p
le
m
e
n
tin
g
m
a
l
w
a
r
e
w
ith
v
ir
tu
a
l
m
a
c
h
in
e
s
”
,
in
: I
EEE S
y
m
p
o
s
iu
m
s
e
c
ur
i
t
y
a
nd pr
i
v
a
c
y
,
2006
,
p
p.
31
4
-
3
27.
[
3
0]
R
ut
k
ow
s
ka
J
,
“
S
ubv
e
r
t
i
ng
v
i
s
t
a
t
m
k
e
r
ne
l
f
or
f
un a
nd pr
of
i
t
”
.
I
n:
B
l
a
c
k
H
a
t
C
onf
e
r
e
nc
e
,
2006.
[
3
1]
B
ah
r
am
S
,
J
i
an
g
X
,
W
an
g
Z
,
G
r
ace M
,
“
D
k
s
m
:
S
ubv
e
r
t
i
ng
v
i
r
t
ua
l
m
a
c
hi
ne
i
nt
r
os
pe
c
t
i
on f
or
f
un a
nd pr
of
i
t
”
,
i
n:
P
r
oc
e
e
di
ng
s
of
t
he
29
th
I
E
E
E
i
nt
e
r
na
t
i
o
na
l
s
y
m
pos
i
um
on r
e
l
i
a
bl
e
di
s
t
r
i
b
ut
e
d s
y
s
t
e
m
,
201
0
[
3
2]
M
et
z C
,
“D
D
o
S
at
t
ack
r
ai
n
s
d
o
w
n
o
n
am
az
o
n
cl
o
u
d
”,
“w
eb
r
ef
er
en
ce” “h
t
t
p
:
/
/
w
w
w
.
t
he
r
e
g
i
s
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c
o.
uk
/
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09/
10/
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a
z
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t
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_out
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g
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/
,
“L
as
t
acces
s
d
at
e”:
2
8
F
eb
2
0
1
7
[
3
3]
P
op
ov
i
c
k
,
H
oc
e
ns
k
i
Z
,
“
C
l
ou
d C
o
m
put
i
ng
S
e
c
ur
i
t
y
i
s
s
ue
s
a
nd c
ha
l
l
e
ng
e
s
”
,
I
n:
P
r
oc
e
e
di
ng
s
of
t
he
33
rd
I
nt
e
r
na
t
i
ona
l
c
onv
e
nt
i
o
n M
I
P
R
O
I
E
E
E
C
om
pu
t
e
r
S
oc
i
e
t
y
W
a
s
hi
ng
t
on D
C
,
U
S
A
,
2
01
0,
pp
.
3
44
-
34
9.
[
3
4]
P
au
l
i
D
,
“A
m
a
zo
n
’
s
ec2
,
eu
cal
y
p
t
u
s
v
u
l
n
er
ab
i
l
i
t
y
d
i
s
co
v
er
ed
”,
“w
eb
r
e
f
er
en
ce
”:
ht
t
p:
/
/
w
w
w
.
c
r
n.
c
om
.
a
u/
N
e
w
s
/
278387
,
a
m
a
z
on
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ec2
-
eu
cal
y
p
t
u
s
-
v
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ln
a
r
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b
ility
-
d
i
s
co
v
er
ed
.
as
p
x
,
“L
as
t
a
cces
s
d
at
e”:
1
5
J
a
nua
r
y
2017.
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