Contemplating Security of Http From SQL Injection and Cross Script

In Existing security system there is authentication at user level the user id and password submitted by user is verified at login process end if the user id and password exist then the user would be able to access the system. But some smart user usually uses SQL injection in order to violate the security of database using wild character of SQL. They sometime use SQL statement too in order to get the login process confused. They pass the sub query of sql in password field instead of password in order to get the confirmation. Here we have to develop a secure system for authentication access and apply SQL INJECTION attack to check its security.