<s>
A	O
zombie	B-Application
cookie	I-Application
is	O
a	O
piece	O
of	O
data	O
that	O
could	O
be	O
stored	O
in	O
multiple	O
locations	O
--	O
since	O
failure	O
of	O
removing	O
all	O
copies	O
of	O
the	O
zombie	B-Application
cookie	I-Application
will	O
make	O
the	O
removal	O
reversible	O
,	O
zombie	B-Application
cookies	I-Application
can	O
be	O
difficult	O
to	O
remove	O
.	O
</s>
<s>
Zombie	B-Application
cookies	I-Application
allow	O
the	O
web	O
traffic	O
tracking	O
companies	O
to	O
retrieve	O
information	O
such	O
as	O
previous	O
unique	B-Protocol
user	I-Protocol
ID	O
and	O
continue	O
tracking	O
personal	O
browsing	O
habits	O
.	O
</s>
<s>
When	O
the	O
user	O
ID	O
is	O
stored	O
outside	O
of	O
a	O
single	O
browser	O
's	O
cookie	O
storage	O
,	O
such	O
as	O
in	O
a	O
header	O
injected	O
by	O
the	O
network	O
into	O
HTTP	O
requests	O
,	O
zombie	B-Application
cookies	I-Application
can	O
track	O
users	O
across	O
browsers	O
on	O
the	O
same	O
machine	O
.	O
</s>
<s>
Zombie	B-Application
cookies	I-Application
are	O
also	O
used	O
to	O
remember	O
unique	O
IDs	O
used	O
for	O
logging	O
into	O
websites	O
.	O
</s>
<s>
For	O
example	O
,	O
counting	O
the	O
same	O
person	O
as	O
two	O
separate	O
unique	B-Protocol
users	I-Protocol
would	O
falsely	O
increase	O
this	O
particular	O
site	O
's	O
unique	B-Protocol
user	I-Protocol
statistic	O
.	O
</s>
<s>
This	O
is	O
why	O
some	O
tracking	O
companies	O
use	O
a	O
type	O
of	O
zombie	B-Application
cookie	I-Application
.	O
</s>
<s>
Possible	O
places	O
in	O
which	O
zombie	B-Application
cookies	I-Application
may	O
be	O
hidden	O
include	O
:	O
</s>
<s>
Every	O
company	O
has	O
their	O
own	O
implementation	O
of	O
zombie	B-Application
cookies	I-Application
and	O
those	O
are	O
kept	O
proprietary	O
.	O
</s>
<s>
An	O
open-source	O
implementation	O
of	O
zombie	B-Application
cookies	I-Application
,	O
called	O
Evercookie	B-Application
,	O
is	O
available	O
.	O
</s>
<s>
In	O
2015	O
,	O
TURN	O
,	O
an	O
online	O
advertising	O
clearinghouse	O
,	O
introduced	O
zombie	B-Application
cookies	I-Application
based	O
on	O
Flash	O
Local	B-Operating_System
Shared	I-Operating_System
objects	I-Operating_System
.	O
</s>
<s>
An	O
academic	O
study	O
of	O
zombie	B-Application
cookies	I-Application
was	O
completed	O
in	O
2009	O
,	O
by	O
a	O
team	O
of	O
researchers	O
at	O
UC	O
Berkeley	O
,	O
where	O
they	O
noticed	O
that	O
cookies	O
which	O
had	O
been	O
deleted	O
,	O
kept	O
coming	O
back	O
,	O
over	O
and	O
over	O
again	O
.	O
</s>
<s>
Ringleader	O
Digital	O
made	O
an	O
effort	O
to	O
keep	O
a	O
persistent	O
user	O
ID	O
even	O
when	O
the	O
user	O
deleted	O
cookies	O
and	O
their	O
HTML5	B-Application
databases	O
.	O
</s>
<s>
The	O
term	O
"	O
zombie	B-Application
cookie	I-Application
"	O
was	O
created	O
by	O
Attorney	O
Joseph	O
H	O
.	O
Malley	O
who	O
initiated	O
the	O
Super-Cookie	O
Class	O
Actions	O
in	O
2010	O
.	O
</s>
<s>
Blending	O
the	O
two	O
ideas	O
,	O
he	O
first	O
coined	O
the	O
phrase	O
Zombie	B-Application
Cookies	I-Application
within	O
his	O
filed	O
Class	O
Actions	O
,	O
as	O
a	O
means	O
to	O
enable	O
the	O
court	O
,	O
jury	O
,	O
and	O
public	O
understand	O
the	O
basis	O
of	O
the	O
litigation	O
.	O
</s>
<s>
The	O
Zombie	B-Application
Cookie	I-Application
lawsuits	O
were	O
filed	O
suit	O
in	O
the	O
United	O
States	O
District	O
Court	O
for	O
the	O
Central	O
District	O
of	O
California	O
against	O
Quantcast	B-Protocol
,	O
Clearspring	O
,	O
VideoEgg	O
,	O
and	O
affiliated	O
sites	O
owned	O
by	O
Walt	O
Disney	O
Internet	O
Group	O
,	O
Warner	O
Bros	O
.	O
and	O
others	O
.	O
</s>
<s>
According	O
to	O
the	O
charges	O
,	O
Adobe	O
Flash	B-Operating_System
cookies	I-Operating_System
are	O
planted	O
to	O
"	O
track	O
Plaintiffs	O
and	O
Class	O
Members	O
that	O
visited	O
non-Clearspring	O
Flash	B-Operating_System
Cookie	I-Operating_System
Affiliates	O
websites	O
by	O
having	O
their	O
online	O
transmissions	O
intercepted	O
,	O
without	O
notice	O
or	O
consent	O
"	O
.	O
</s>
<s>
Consumer	O
outrage	O
related	O
to	O
Flash	B-Operating_System
cookies	I-Operating_System
and	O
violation	O
of	O
consumers	O
 '	O
privacy	O
caused	O
U.S.	O
Congressional	O
Hearings	O
,	O
led	O
by	O
Senators	O
Al	O
Franken	O
and	O
John	O
Rockefeller	O
.	O
</s>
<s>
Reportedly	O
,	O
the	O
"	O
Zombie	B-Application
Cookie	I-Application
"	O
,	O
aka	O
Flash	B-Operating_System
Cookie	I-Operating_System
filings	O
,	O
forced	O
Adobe	O
Systems	O
Inc	O
.	O
to	O
stop	O
processing	O
flash	B-Operating_System
cookies	I-Operating_System
on	O
98%	O
of	O
all	O
consumers	O
 '	O
computing	O
devices	O
.	O
</s>
<s>
The	O
online	O
advertising	O
clearinghouse	O
TURN	O
implemented	O
zombie	B-Application
cookies	I-Application
on	O
Verizon	B-Application
mobile	O
phones	O
,	O
using	O
a	O
hidden	O
,	O
unremovable	O
number	O
by	O
which	O
Verizon	B-Application
could	O
track	O
customers	O
.	O
</s>
<s>
After	O
an	O
article	O
by	O
ProPublica	O
revealed	O
this	O
fact	O
in	O
January	O
2015	O
,	O
TURN	O
claimed	O
it	O
had	O
suspended	O
usage	O
of	O
their	O
zombie	B-Application
cookies	I-Application
.	O
</s>
