Saturday, February 19, 2011

Hack your Own Web Project ? SQL Injection

SQL Injection

SQL Injection like this





Login Java Code


String userid = request.getParameter("userid");
String password = request.getParameter("password");
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
connection = DriverManager.getConnection("jdbc:odbc:projectDB");

query = "SELECT * FROM Users WHERE user_id ='" + userid + "' AND password ='" + password +"'";

PreparedStatement ps = connection.prepareStatement(query);
ResultSet users = ps.executeQuery();

if(users.next()){

//some thing here
}
else{

}

Injection Works like this
query = "SELECT * FROM Users WHERE user_id ='' OR 1=1; /* AND password ='*/--'";

Login PHP Code;

Username = ' OR 1=1;//
Password = ....
$myusername=$_POST['usr'];
$mypassword=$_POST['pwd'];

$sql="SELECT * FROM users WHERE user='$myusername' and password='$mypassword'";

$result=mysql_query($sql);
$count=mysql_num_rows($result);

if($count==1){

//some code
}
else {

}
Injection Works like this
$sql="SELECT * FROM users WHERE user=''OR 1 = 1;//' and password='....'";


How to avoid these mistakes Use addSlashes() function adding slashes(/) to the string in java and php

//Java Code
addSlashes(String userid);

// PHP Code
$myusername=addslashes($_POST['usr'];);
Hacker is intelligent than programmer. So always hide the file extension (eg: *.jsp,*.php,*.asp).

http://xyz.com/login.php to http://xyz.com/login
http://xyz.com/login to http://xyz.com/signin.do
In Java redirect this URL links using Web.xml file and inn php write .htaccess file in root directory.

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