<s>
Insecure	B-Protocol
direct	I-Protocol
object	I-Protocol
reference	I-Protocol
(	O
IDOR	B-Protocol
)	O
is	O
a	O
type	O
of	O
access	O
control	O
vulnerability	O
in	O
digital	O
security	O
.	O
</s>
<s>
This	O
can	O
occur	O
when	O
a	O
web	B-Application
application	I-Application
or	O
application	B-Application
programming	I-Application
interface	I-Application
uses	O
an	O
identifier	O
for	O
direct	O
access	O
to	O
an	O
object	O
in	O
an	O
internal	O
database	O
but	O
does	O
not	O
check	O
for	O
access	O
control	O
or	O
authentication	O
.	O
</s>
<s>
A	O
directory	B-Protocol
traversal	I-Protocol
attack	I-Protocol
is	O
considered	O
a	O
special	O
case	O
of	O
a	O
IDOR	B-Protocol
.	O
</s>
<s>
The	O
vulnerability	O
is	O
of	O
such	O
significant	O
concern	O
that	O
for	O
many	O
years	O
it	O
was	O
listed	O
as	O
one	O
of	O
the	O
Open	O
Web	B-Application
Application	I-Application
Security	O
Project	O
’s	O
(	O
OWASP	O
)	O
Top	O
10	O
vulnerabilities	O
.	O
</s>
<s>
In	O
November	O
2020	O
,	O
the	O
firm	O
Silent	O
Breach	O
identified	O
an	O
IDOR	B-Protocol
vulnerability	O
with	O
the	O
United	O
States	O
Department	O
of	O
Defense	O
web	O
site	O
and	O
privately	O
reported	O
it	O
via	O
the	O
DOD	O
's	O
Vulnerability	O
Disclosure	O
Program	O
.	O
</s>
<s>
It	O
was	O
reported	O
that	O
the	O
Parler	B-Application
social	O
networking	O
service	O
used	O
sequential	O
post	O
IDs	O
,	O
and	O
that	O
this	O
had	O
enabled	O
the	O
scraping	O
of	O
terabytes	O
of	O
data	O
from	O
the	O
service	O
in	O
January	O
2021	O
.	O
</s>
