Wednesday, September 7, 2011


I was able to play with a mock MySQL database the other day to see if I was able to acquire a specific username and password combination. The database was vulnerable to SQL injection through an online web application that allowed users to view pages through a php script that took a numerical value and passed it straight to the SQL statement. By modifying the number to equal a value that there was not a page for, I inserted an OR statement after that value and was able to redirect the SQL statement from there. After a few initial tests, I saw that the web application was indeed filtering the error messages that the database threw back, therefore I had to use "blind" SQL injection. If you want to know more about blind SQL injection, OWASP has a great page HERE.

After asking the database quite a few "yes or no" questions through SQL statements, I decided to try out some security tools that I had never used before. One of which was a beautiful little tool called SQLmap. After pointing it at the web application, SQLmap began to laugh at my manual attempts to fingerprint the database and enumerate its tables and within minutes it had finished its task. I was floored. How in the world did this thing produce the results that it did in such a short amount of time. Being the kind of person who has to know how things work, I fired up wireshark and watched as SQLmap sent packets faster than I could scroll down. Once it took a breather I filtered through the packets and looked at the SQL statements that it was sending to the application. It looked like SQLmap was using the technique discussed on the OWASP page that enumerates each character individually through true or false statements. If the statement is true the page will return with the correct item as if it were just a simple ID request. If the statement is false, the page will return with some sort of predefined error page. And seeing as though a program is capable of being much smarter and faster in this type of scenario, this is the ideal way to perform a blind SQL injection due to the fact that it saves ALOT of time.

Thanks to SQLmap I was able to acquire the dummy username and password. Needless to say I was highly impressed by this tool and look forward to becoming more skilled with it, as well as learning more about database security.

For a list of SQLmap's features check out their page HERE.

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