<s>
In	O
a	O
semantic	B-Protocol
URL	I-Protocol
attack	I-Protocol
,	O
a	O
client	B-Protocol
manually	O
adjusts	O
the	O
parameters	O
of	O
its	O
request	O
by	O
maintaining	O
the	O
URL	O
's	O
syntax	B-Application
but	O
altering	O
its	O
semantic	B-Application
meaning	O
.	O
</s>
<s>
This	O
attack	O
is	O
primarily	O
used	O
against	O
CGI	B-Language
driven	O
websites	O
.	O
</s>
<s>
A	O
similar	O
attack	O
involving	O
web	B-Application
browser	I-Application
cookies	I-Application
is	O
commonly	O
referred	O
to	O
as	O
cookie	B-Application
poisoning	I-Application
.	O
</s>
<s>
After	O
they	O
answer	O
the	O
security	O
question	O
correctly	O
,	O
the	O
web	O
page	O
will	O
arrive	O
to	O
the	O
following	O
web	B-General_Concept
form	I-General_Concept
where	O
the	O
users	O
can	O
enter	O
their	O
alternative	O
e-mail	O
address	O
:	O
</s>
<s>
Because	O
this	O
web	B-General_Concept
form	I-General_Concept
is	O
using	O
the	O
GET	O
data	O
method	O
,	O
when	O
the	O
user	O
submits	O
alternative@emailexample.com	O
as	O
the	O
e-mail	O
address	O
where	O
the	O
user	O
wants	O
the	O
password	O
to	O
be	O
sent	O
to	O
,	O
</s>
<s>
This	O
URL	O
appears	O
in	O
the	O
location	O
bar	O
of	O
the	O
browser	O
,	O
so	O
the	O
user	O
can	O
identify	O
the	O
username	O
and	O
the	O
e-mail	O
address	O
through	O
the	O
URL	B-Protocol
parameters	I-Protocol
.	O
</s>
<s>
If	O
the	O
resetpassword.php	O
accepts	O
these	O
values	O
,	O
it	O
is	O
vulnerable	O
to	O
a	O
semantic	B-Protocol
URL	I-Protocol
attack	I-Protocol
.	O
</s>
<s>
One	O
method	O
of	O
avoiding	O
semantic	B-Protocol
URL	I-Protocol
attacks	I-Protocol
is	O
by	O
using	O
session	O
variables	O
.	O
</s>
<s>
However	O
,	O
session	O
variables	O
can	O
be	O
vulnerable	O
to	O
other	O
types	O
of	O
attacks	O
such	O
as	O
session	B-Protocol
hijacking	I-Protocol
and	O
cross-site	O
scripting	O
.	O
</s>
