for those who still don't have an attached authenticator to your WoW account (because for example your phone doesn't support it) here's the Windows application equivalent of it. It supports all WoW regions (Europe, Russia, America, Oceania, China, Taiwan and Korea). Just run it and right-click it to see all available options.
DOWNLOAD LINK: http://www.gamefront.com/files/21374332/WinAuth_1_6_1122_zip
Security of your WoW account is the most essential aspect so I encourage you to use it if you still haven't (plus you'll get the Core Hound Pup for every existing and future character on your account).
EDIT: If you're unable to login into the game or on your Battle.net account (you get the message Login Failed, Wrong Password) right-click on the Authenticator application and choose Sync Server Time. After that everything will be back to normal.