<s>
Internet	B-Application
Optimizer	I-Application
,	O
also	O
known	O
as	O
DyFuCA	B-Application
is	O
an	O
adware	O
and	O
a	O
spyware	O
program	O
,	O
which	O
first	O
appeared	O
in	O
2003	O
.	O
</s>
<s>
It	O
typically	O
redirects	O
Internet	B-Application
Explorer	I-Application
error	O
pages	O
to	O
advertising	O
pages	O
.	O
</s>
<s>
It	O
may	O
be	O
installed	O
as	O
a	O
drive-by	O
download	O
via	O
an	O
ActiveX	B-Application
component	I-Application
,	O
usually	O
via	O
nuisance	O
affiliate	O
porn	O
webpage	O
popups	O
.	O
</s>
<s>
Users	O
suspicions	O
are	O
lulled	O
by	O
its	O
installer	O
title	O
as	O
Internet	B-Application
Optimizer	I-Application
under	O
the	O
guise	O
of	O
the	O
name	O
of	O
the	O
otherwise	O
unrelated	O
Moneytree	O
,	O
while	O
the	O
C&C	O
domains	O
accessed	O
were	O
usually	O
named	O
with	O
the	O
prefix	O
"	O
mtree	O
"	O
.	O
</s>
<s>
When	O
users	O
follow	O
a	O
broken	O
link	O
or	O
enter	O
an	O
erroneous	O
URL	O
,	O
instead	O
of	O
the	O
browser	O
's	O
internal	O
default	B-Protocol
error	I-Protocol
status	I-Protocol
page	I-Protocol
,	O
they	O
see	O
an	O
internet	O
page	O
of	O
advertisements	O
.	O
</s>
<s>
Password-protected	O
Web	O
sites	O
or	O
pages	O
will	O
prompt	O
for	O
a	O
missing	O
or	O
required	O
user	O
name	O
and	O
password	O
via	O
a	O
pop-up	O
request	O
,	O
this	O
HTTP	O
Basic	O
authentication	O
uses	O
the	O
same	O
mechanism	O
as	O
HTTP	O
errors	O
,	O
thus	O
Internet	B-Application
Optimizer	I-Application
inadvertently	O
interferes	O
and	O
makes	O
it	O
impossible	O
for	O
the	O
user	O
to	O
access	O
password-protected	O
sites	O
or	O
pages	O
.	O
</s>
<s>
It	O
uses	O
the	O
"	O
Browser	B-Application
Helper	I-Application
Object	I-Application
"	O
or	O
BHO	O
interface	O
,	O
and	O
as	O
such	O
,	O
it	O
loads	O
whenever	O
MS	B-Application
Internet	I-Application
Explorer	I-Application
starts	O
and	O
may	O
be	O
ignored	O
by	O
firewalls	O
or	O
not	O
flagged	O
by	O
anti-virus	O
software	O
,	O
as	O
it	O
is	O
seen	O
as	O
a	O
legitimate	O
part	O
of	O
the	O
browser	O
application	O
.	O
</s>
