MySQL Injection Tutorial Described

TABLE OF CONTENT:
#INTRO
#WHAT IS DATABASE?
#WHAT IS SQL INJECTION?
#BYPASSING LOGINS
#ACCESSING SECRET DATA
#Checking for vulnerability
#Find the number of columns
#Addressing vulnerable part
#Finding MySQL version
#MySQL 5 or above injection
#MySQL 4 injection
#MODIFYING SITE CONTENT
#SHUTTING DOWN THE MySQL SERVER
#LOADFILE
#MySQL ROOT
#MAJOR MySQL COMMANDS
#FINALIZING THE INJECTION TUTORIAL
#REFERENCES
#SECURITY SITES
#WARGAMEZ SITES
#GREETZ AND SHOUTZ
#THE END
INTRO!!
In this tutorial, I will demonstrate the infamous MySQL injection in newbie perspective so that all the newbies become able to become successful SQL injector. But, be sure to check various php & mysql functions in various sites which will help you a lot... lets begin our walkthrough of SQL injection.
WHAT IS DATABASE?
Just general info.. Database is the application that stores a collection of data. Database offers various APIs for creating, accessing and managing the data it holds. And database(DB) servers can be integrated with our web development so that we can pick up the things we want from the database without much difficulties. DB may hold various critical informations like usernames, passwords, credit cares,etc. So, DB need to be secured but many DB servers running are insecured either bcoz of their vulnerability or bcoz of poor programming handles. To name few DB servers, MySQL(Open source), MSSQL, MS-ACCESS, Oracle, Postgre SQL(open source), SQLite, etc.
WHAT IS SQL INJECTION?
SQL injection is probably the most abundant programming flaw that exists on the internet at present. It is the vulnerability through which unauthorized person can access the various critical and private dat. SQL injection is not a flaw in the web or db server but but is a result of the poor and inexperienced programming practices. And it is one of the deadliest as well as easiest attack to execute from remote location.
In SQL injection, we interact with DB server with the various commands and get various data from it. In this tutorial, I would be discussing 3 aspects of SQL injection namely bypassing logins, accessing the secret data and modifying the page contents. So lets head forward on our real walkthrough..
CTD...
BYPASSING LOGINS
Suppose, a site has a login form & only the registered users are allowed to enter the site. Now, say u wanted to bypass the login and enter the site as the legitimate user. If the login scriptblock is not properly sanitized by the programmer, u may have luck to enter the site. U might be able to login into the site without knowing the real username and real password by just interacting with the DB server. So, isn't that the beauty of SQL injection??
Let's see an example, where the username admin with the password pass123 can login to the site. Suppose, the SQL query for this is carried out as below:
SELECT USER from database WHERE username='admin' AND password='pass123'
And if above SELECT command evaluates true, user will be given access to the site otherwise not. Think what we could do if the scriptblock is not sanitized. This opens a door for the hackers to gain illegal access to the site.
In this example, the attacker can enter the following user data in the login form:
username: a or 1 =1--
password:blank
So, this would make our query as:
SELECT USER from database WHERE username='a' or 1 =1-- AND password=''
Note that -- is the comment operator and anything after it will be ignored as a comment. There exists another comment operator which is /*.
So our above query becomes:
SELECT USER from database WHERE username='a' or 1 =1
Now this query evaluates true even if there is no user called 'a' bcoz 1 =1 is always true and using OR makes the query return true when one of the query is true. And this gives access to the site admin panel.
There can be various other username and password combinations to play with the vulnerable sites. U can create ur own new combinations for the site login.
Few such combinations are:
username:' or 1 ='1 password:' or 1 ='1
username:' or '1 '='1 ' password:' or '1 '='1'
username:or 1 =1 password:or 1 =1
and there are many more cheat sheets. Just google. In fact, you can create your own such combination to bypass logins..
That's all about bypassing logins.
CTD...

ACCESSING SECRET DATA
SQL injection is not essentially done for bypassing logins only but it is also used for accessing the sensitive and secret data in the DB servers. This part is long, so I would be discussing in the subsections.
Sub-section 1 :
Checking for vulnerability
Suppose, u got a site:
http://www.site.com/article.ph p?id=5
Now to check if it is vulnerable, u would simply add ' in the end i.e. where id variable is assigned.
So, it is:
www.site.com/article.php?id=5'
Now if the site is not vulnerable, it filters and the page loads normally.
But, if it doesn't filter the query string, it would give the error something like below:
"MySQL Syntax Error By '5 '' In Article.php on line 15."
or
error that says us to check the correct MySQL version or MySQL Fetch error or sometimes just blank page. The error may be in any form. So it makes us sure that the site is vulnerable.
Also just using ' may not be the sure test; so you may try different things like:
www.site.com/article.php?id=5 union select 1--
If you get error with this, you again come to know that its vulnerable... Just try different things..
Read part 2 to continue...