<s>
Firesheep	B-Operating_System
was	O
an	O
extension	O
for	O
the	O
Firefox	B-Application
web	I-Application
browser	I-Application
that	O
used	O
a	O
packet	B-Protocol
sniffer	I-Protocol
to	O
intercept	O
unencrypted	O
session	B-Application
cookies	I-Application
from	O
websites	O
such	O
as	O
Facebook	O
and	O
Twitter	O
.	O
</s>
<s>
The	O
plugin	O
eavesdropped	O
on	O
Wi-Fi	O
communications	O
,	O
listening	O
for	O
session	B-Application
cookies	I-Application
.	O
</s>
<s>
When	O
it	O
detected	O
a	O
session	O
cookie	B-Application
,	O
the	O
tool	O
used	O
this	O
cookie	B-Application
to	O
obtain	O
the	O
identity	O
belonging	O
to	O
that	O
session	O
.	O
</s>
<s>
The	O
collected	O
identities	O
(	O
victims	O
)	O
are	O
displayed	O
in	O
a	O
side	O
bar	O
in	O
Firefox	B-Application
.	O
</s>
<s>
The	O
extension	O
was	O
released	O
October	O
2010	O
as	O
a	O
demonstration	O
of	O
the	O
security	O
risk	O
of	O
session	B-Protocol
hijacking	I-Protocol
vulnerabilities	O
to	O
users	O
of	O
web	O
sites	O
that	O
only	O
encrypt	O
the	O
login	O
process	O
and	O
not	O
the	O
cookie(s )	O
created	O
during	O
the	O
login	O
process	O
.	O
</s>
<s>
Despite	O
the	O
security	O
threat	O
surrounding	O
Firesheep	B-Operating_System
,	O
representatives	O
for	O
Mozilla	O
Add-ons	B-Operating_System
stated	O
initially	O
that	O
it	O
would	O
not	O
use	O
the	O
browser	O
's	O
internal	O
add-on	B-Operating_System
blacklist	O
to	O
disable	O
use	O
of	O
Firesheep	B-Operating_System
,	O
as	O
the	O
blacklist	O
has	O
only	O
been	O
used	O
to	O
disable	O
spyware	O
or	O
add-ons	B-Operating_System
which	O
inadvertently	O
create	O
security	O
vulnerabilities	O
,	O
as	O
opposed	O
to	O
attack	O
tools	O
(	O
which	O
may	O
legitimately	O
be	O
used	O
to	O
test	O
the	O
security	O
of	O
one	O
's	O
own	O
systems	O
)	O
.	O
</s>
<s>
Since	O
then	O
,	O
Firesheep	B-Operating_System
has	O
been	O
removed	O
from	O
the	O
Firefox	B-Operating_System
addon	I-Operating_System
store	O
.	O
</s>
