<s>
Back	B-Protocol
Orifice	I-Protocol
2000	I-Protocol
(	O
often	O
shortened	O
to	O
BO2k	B-Protocol
)	O
is	O
a	O
computer	B-Application
program	I-Application
designed	O
for	O
remote	B-Protocol
system	I-Protocol
administration	I-Protocol
.	O
</s>
<s>
It	O
enables	O
a	O
user	O
to	O
control	O
a	O
computer	O
running	O
the	O
Microsoft	B-Application
Windows	I-Application
operating	I-Application
system	I-Application
from	O
a	O
remote	O
location	O
.	O
</s>
<s>
The	O
name	O
is	O
a	O
pun	O
on	O
Microsoft	B-General_Concept
BackOffice	I-General_Concept
Server	I-General_Concept
software	O
.	O
</s>
<s>
BO2k	B-Protocol
debuted	O
on	O
July	O
10	O
,	O
1999	O
,	O
at	O
DEF	O
CON	O
7	O
,	O
a	O
computer	O
security	O
convention	O
in	O
Las	O
Vegas	O
,	O
Nevada	O
.	O
</s>
<s>
It	O
was	O
a	O
successor	O
to	O
the	O
cDc	O
's	O
Back	B-Protocol
Orifice	I-Protocol
remote	B-Protocol
administration	I-Protocol
tool	O
,	O
released	O
the	O
previous	O
year	O
.	O
</s>
<s>
,	O
BO2k	B-Protocol
was	O
being	O
actively	O
developed	O
.	O
</s>
<s>
Whereas	O
the	O
original	O
Back	B-Protocol
Orifice	I-Protocol
was	O
limited	O
to	O
the	O
Windows	B-Application
95	I-Application
and	O
Windows	B-Device
98	I-Device
operating	O
systems	O
,	O
BO2k	B-Protocol
also	O
supports	O
Windows	B-Device
NT	I-Device
,	O
Windows	B-Application
2000	I-Application
and	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
Some	O
BO2k	B-Protocol
client	O
functionality	O
has	O
also	O
been	O
implemented	O
for	O
Linux	B-Operating_System
systems	O
.	O
</s>
<s>
In	O
addition	O
,	O
BO2k	B-Protocol
was	O
released	O
as	O
free	B-Application
software	I-Application
,	O
which	O
allows	O
one	O
to	O
port	O
it	O
to	O
other	O
operating	O
systems	O
.	O
</s>
<s>
BO2k	B-Protocol
has	O
a	O
plugin	B-Application
architecture	O
.	O
</s>
<s>
The	O
optional	O
plugins	B-Application
include	O
:	O
</s>
<s>
Back	B-Protocol
Orifice	I-Protocol
and	O
Back	B-Protocol
Orifice	I-Protocol
2000	I-Protocol
are	O
widely	O
regarded	O
as	O
malware	O
,	O
tools	O
intended	O
to	O
be	O
used	O
as	O
a	O
combined	O
rootkit	O
and	O
backdoor	O
.	O
</s>
<s>
For	O
example	O
,	O
at	O
present	O
many	O
antivirus	B-Application
software	I-Application
packages	O
identify	O
them	O
as	O
Trojan	O
horses	O
.	O
</s>
<s>
This	O
classification	O
is	O
justified	O
by	O
the	O
fact	O
that	O
BO2k	B-Protocol
can	O
be	O
installed	O
by	O
a	O
Trojan	O
horse	O
,	O
in	O
cases	O
where	O
it	O
is	O
used	O
by	O
an	O
unauthorized	O
user	O
,	O
unbeknownst	O
to	O
the	O
system	O
administrator	O
.	O
</s>
<s>
There	O
are	O
several	O
reasons	O
for	O
this	O
,	O
including	O
:	O
the	O
association	O
with	O
cDc	O
;	O
the	O
tone	O
of	O
the	O
initial	O
product	O
launch	O
at	O
DEF	O
CON	O
(	O
including	O
that	O
the	O
first	O
distribution	O
of	O
BO2k	B-Protocol
by	O
cDc	O
was	O
infected	O
by	O
the	O
CIH	O
virus	O
)	O
;	O
the	O
existence	O
of	O
tools	O
(	O
such	O
as	O
"	O
Silk	O
Rope	O
"	O
)	O
designed	O
to	O
add	O
BO2k	B-Protocol
dropper	O
capability	O
to	O
self-propagating	O
malware	O
;	O
and	O
the	O
fact	O
that	O
it	O
has	O
actually	O
widely	O
been	O
used	O
for	O
malicious	O
purposes	O
.	O
</s>
<s>
The	O
most	O
common	O
criticism	O
is	O
that	O
BO2k	B-Protocol
installs	O
and	O
operates	O
silently	O
,	O
without	O
warning	O
a	O
logged-on	O
user	O
that	O
remote	B-Protocol
administration	I-Protocol
or	O
surveillance	O
is	O
taking	O
place	O
.	O
</s>
<s>
According	O
to	O
the	O
official	O
BO2k	B-Protocol
documentation	O
,	O
the	O
person	O
running	O
the	O
BO2k	B-Protocol
server	O
is	O
not	O
supposed	O
to	O
know	O
that	O
it	O
is	O
running	O
on	O
their	O
computer	O
.	O
</s>
<s>
BO2k	B-Protocol
developers	O
counter	O
these	O
concerns	O
in	O
their	O
Note	O
on	O
Product	O
Legitimacy	O
and	O
Security	O
,	O
pointing	O
out	O
—	O
among	O
other	O
things	O
—	O
that	O
some	O
remote	B-Protocol
administration	I-Protocol
tools	O
widely	O
recognized	O
as	O
legitimate	O
also	O
have	O
options	O
for	O
silent	O
installation	O
and	O
operation	O
.	O
</s>
