diff --git a/program/include/rcmail.php b/program/include/rcmail.php
index b2ab79ab8..81a1c817c 100644
--- a/program/include/rcmail.php
+++ b/program/include/rcmail.php
@@ -596,6 +596,8 @@ class rcmail extends rcube
 
         // try to log in
         if (!$storage->connect($host, $username, $pass, $port, $ssl)) {
+            // Wait a second to slow down brute-force attacks (#1490549)
+            sleep(1);
             return false;
         }