SQL Injection involves entering SQL code into web forms, eg. login fields, or into the browser address field, to access and manipulate the database behind the site, system or application.
When you enter text in the Username and Password fields of a login screen, the data you input is typically inserted into an SQL command. This command checks the data you've entered against the relevant table in the database. If your input matches table/row data, you're granted access (in the case of a login screen). If not, you're knocked back out.
The Simple SQL Injection Hack
Click on here to view the sample SQL hack
There are tools to automate the process of SQL Injection into login and other fields. One hacker process, using a specific tool, will be to seek out a number of weak targets using Google (searching for login.asp, for instance), then insert a range of possible injection strings (like those listed above, culled from innumerable Injection cheat-sheets on the Web), add a list of proxies to cover his movements, and go play Xbox while the program automates the whole injection process.
This involves uploading malicious files to inject SQL and exploit other vulnerabilities. It's a topic which was deemed beyond the scope of this report, but you can view this Page if you'd like to learn more.
SQL Injection in the Browser Address Bar
Injections can also be performed via the browser address bar. I don't mean to have a pop at Microsoft, but when it comes to such vulnerabilities, HTTP GET requests with URLs of the following form are most often held to be vulnerable:
Try adding an SQL command to the end of a URL string like this, just for kicks:
http://somesite.com/index.asp?id=10 AND id=11
See if both articles come up. Don't shoot your webmaster just yet if it's your own site and you get two articles popping up: this is real low-level access to the database. But some such sites will be vulnerable. Try adding some other simple SQL commands to the end of URLs from your own site, to see what happens.
As we saw above, access to the database raises a number of attractive promises. The database structure can be mapped by a expert hacker through ill-conceived visibility of error messages — this is called database footprinting — and then this knowledge of table names and so forth can be used to gain access to additional data. Revealing error messages are manna - they can carry invaluable table name and structural details.
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