SQL injection is a code injection technique, used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker).
More serious sql injection attacks
$name_evil = "'; DELETE FROM customers WHERE 1 or username = '"; // our MySQL query builder really should check for injection $query_evil = "SELECT * FROM customers WHERE username = '$name_evil'"; // the new evil injection query would include a DELETE statement echo "Injection: " . $query_evil; injection prevention - mysql_real_escape_string()
//NOTE: you must be connected to the database to use this function! // connect to MySQL $name_bad = "' OR 1'"; $name_bad = mysql_real_escape_string($name_bad); $query_bad = "SELECT * FROM customers WHERE username = '$name_bad'"; echo "Escaped Bad Injection: <br />" . $query_bad . "<br />"; $name_evil = "'; DELETE FROM customers WHERE 1 or username = '"; $name_evil = mysql_real_escape_string($name_evil); $query_evil = "SELECT * FROM customers WHERE usernam