Ticket #10026: 10026.patch

wp-login.php

@@ -41 +41 @@
 function login_header($title = 'Log In', $message = '', $wp_error = '') {
         global $error;
 
+        // Don't index any of these forms
+        add_filter( 'pre_option_blog_public', create_function( '$a', 'return 0;' ) );
+        add_action( 'login_head', 'noindex' );
+
         if ( empty($wp_error) )
                 $wp_error = new WP_Error();
         ?>