网站最近被黑了，希望有助于改进我的登录脚本

Question

Yesterday my site was hacked, the hacker managed to login to the admin area and post a blog which contained a redirect link to his website. So Im asking for a bit of help in making my login secure.

Here is my script:

    $username = $_POST['username'];
    $password = md5_base64($_POST['password']);

    $stmt = $mysqli->prepare("SELECT id, username, password, permission FROM user WHERE username = ? AND password = ?");
    $stmt->bind_param('ss', $username, $password);
    $stmt->execute();
    $stmt->bind_result($userid, $username, $password, $permission);
    $stmt->store_result();

    if(($numRows = $stmt->num_rows) > 0)
    {   
        $response_array['status'] = "success";
        $response_array['message'] = "Logged in";
    }
    else
    {
        $response_array['status'] = "error";
        $response_array['message'] = "Sorry, Wrong Username/Password Combination" .$password;                   
    }

Heres the md5_base64 function:

    function md5_base64 ( $data ) 
    { 
       return preg_replace('/=+$/','',base64_encode(md5($data,true))); 
    } 

Any help, advice and improvements are greatly appreciated.

Answer 1

A little bit information regarding how attack happened is required.

1. It may be the possibility of SQL Injection rather than programming defect.

2. Always sanitize your input before sending the query to database , a single quote can create a SQL Injection attack.

3. Watch for default passwords or simple passwords like admin , admin123 , 12345 etc.

4. One can easily guess or can use Dictionary attack to crack it.

   Use Complex Passwords as well.

5. If you are using Database , use Prepared Statement .

Regards

Anshul Katta