Theses days, there’s a lot of talk about WordPress security due to recent issues. Is your blog secure? Here is a quick tip that you can easily implement to prevent displaying useful message to potential blog hackers. Adding this PHP code to the functions.php of your wordpress theme will disable the login errors that are displayed to users. Help prevents people from guessing your user name or password.
add_filter('login_errors', create_function('$a', "return null;"));