Beginner PHP Tutorial - 153 - SQL Injection Part 3 Video Lecture | PHP for Absolute Beginners: From Novice to PHP Master - Web Development

so let's go back to our database so we
can monitor what we're doing here and
click back on users okay so we're going
to start by opening our text editor and
we're going to connect to our MySQL
server and then connect to our database
so I'm not going to be doing this
properly because in this video I'm just
demonstrating SQL injection so I'm just
going to use a standard MySQL connect
function it takes three parameters if
you haven't already looked to this I do
have another video on it so go back and
again have a look at this my username is
root and my password is just blank and
I'm going to say MySQL select DB and
this is a underscore database so let's
just echo out a confirmation message
here just to check the we're connecting
successfully so let's refresh there and
it to do that okay so we've got an OK
message there so we've successfully
connected to the database let's start
creating our form so we need to take a
username and a password with value and
we're doing this I'm going to put both
fields equal to text values so you can
see what we're typing in in our password
field so I'm going to say form action
and I need to set a property for method
as well and the form action is going to
be index dot PHP we're going to come
back to that and the method is going to
be post ok so we want user name and we
want to take an input and the type is
text the name is a username and that's
it so now what we can do is say password
we'll bring this down a line even though
we're not breaking down the line we'll
just bring it down for all right
neatness we'll set input type is text
name equals password this is the users
password and then again we'll just line
down and we'll say add a submit button
here it's a very basic HTML form that
we're creating let's just preview it in
our browser and yeah we've got user name
and password so we can type something
here and we can type something here ok
so we can see the password you'd usually
set it to the type of password so you
can't actually see the password but for
now we're going to we're going to set it
to text so we see what we're doing so
when the for
resubmits we need to first of all check
if at the posted you slim a post with
posted password are set so we use the is
set language constructor we say is set
post username and oh sorry and so we use
our and operator and we say is set
dollar underscore post password so if
these are both set we can now assign
them to our own variable so username is
going to equal dollar underscore post
username and password is going to equal
dollar underscore post password so let's
just echo these out so we see we can see
that this is this is giving us back our
input so I'm going to type a in here and
B in here so what we should get back is
just a B next to each other okay yes so
our variable two successfully being
picked up using the post username the
post password so you can now get rid of
this echo so it's good to test your
program as you go along now I'm going to
say if not empty username and not empty
password
eko okay so now let's test this and
submit nothing okay nothing happens now
let's test submit a and B click Submit
okay so we are checking just doing some
basic form validation the username and
password must exist okay so now what we
need to do is we need to structure our
query so our query is going to equal and
like I said if you've already seen this
you'll know exactly what we're doing the
query is going to equal select ID from
users much like I demonstrated just
about five minutes ago so select ID from
users where username equals something
here and password equals something here
so let's just put them in apostrophes so
where username equals something and
possibly become something this is
obvious it's where username equals user
name and password equals password so now
we can create a new variable called
query run and we can run this query so
MySQL query and actually process that
query through pH sorry through MySQL now
this is the dangerous line because what
we've done here is we've processed this
query and so far we've given absolutely
no protection whatsoever to protect
against the SQL injection and I'll show
you in a minute we're going to look at
something inside the PHP dot ini file so
the PHP configuration file which which
doesn't automatically escape characters
such as a single quotation mark so
usually when you submit data with a
single quotation I can automatically put
a forward slash in front of it as a
security measure but at the moment I've
got it disabled in my PHP ini file so
that's the first way we're going to look
at protecting against SQL injection so
let's first of all just comment out
these and let's go ahead and echo out
the username
and we'll break down the line and we
will echo out the password as well and
I'm going to show you exactly what I
mean
now remember earlier we talked about
quotation marks inside inside our
queries and quotation marks are deadly
as far as query goes because what people
can do like we like we and looked at
earlier is end a specific statement if
you like and and create something else
so we can add or key words in and we can
end different in different lines or n
different like we're equals and we can
end here and then start something else
and then end here again just like I
demonstrated earlier