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How can i update a table using SQL Injection?

Answer 1

+6 A:

You may want to try entering Robert'); DROP TABLE students; -- in your form :)

alt text

In the above xkcd cartoon, Bobby was probably asked to fill in his name in a form, but he mischievously inserted Robert'); DROP TABLE students; -- as his name. Now imagine if that input was used in this query:

SELECT * FROM students WHERE name = '$input'

As you can see, if we substitute $input for what Bobby entered, you'll get this

SELECT * FROM students WHERE name = 'Robert'); DROP TABLE students; --'

Which are two very valid SQL commands, and a comment.

You may also want to research earlier Stack Overflow questions on SQL Injection.

Daniel Vassallo 2010-10-08 11:42:00

Is it possible to change by updating the table by entering the query in URL. kindly explain

Fero 2010-10-08 11:45:31

@Fero: Yes it is. For example, if you use the querystring from the URL, and insert it into a `SELECT` statement, as in `SELECT * FROM users WHERE username = '$querystring';` Then whatever you pass as the querystring can easily terminate that `SELECT` statement, and execute any another statement, as in the above cartoon.

Daniel Vassallo 2010-10-08 11:50:14

Thanks Dany.. Is there any sites or blogs which explain it breifly...

Fero 2010-10-08 11:51:43

In the above cartoon, Bobby was probably asked to fill in his name in a form, but he mischievously inserted `Robert'); DROP TABLE students; --`... Now imagine if that input was used in this query: `SELECT * FROM students WHERE name = '$input'`... As you can see, if you substitute `$input` for what Bobby entered, you'll get this: `SELECT * FROM students WHERE name = 'Robert'); DROP TABLE students; --'`, which are two valid SQL commands.

Daniel Vassallo 2010-10-08 11:53:23

@Fero: You may want to start with the link that @Piskvor suggested in the above comments. Then I'd recommend going through Stack Overflow.

Daniel Vassallo 2010-10-08 11:54:47

Thank u very much dany...

Fero 2010-10-08 11:54:57

But its throwing an while i worked with phpmyadmin

Fero 2010-10-08 12:13:39

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How can i update a table using SQL Injection?

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