If you want add an extra layer of WordPress security around all your sites, then follow these easy steps in this video. The plugin called out in this video is very reliable and will not cost you a cent.
There are a number of no-cost plugins out there that can do similar things, yet I have had the best luck with the Login Lock WordPress plugin. It works well with all my WordPress themes and provides the trageted information I need to protect my sites.
Add this plugin to the configuration recommended and you will have yourself a rather robust configuration to stop about 90% of all hacks.
Keep in mind you only need to do this if you are experiencing a high number of brute force entries. If you are only getting a few here and there, then it might not be worth your time. Yet if you are like me and get 10 to 15 attempts a day, then this method will definitely stop them dead in their tracks.
If you are not using Login Lock, then you will have no idea how many attempts are being made on your sites. You may be surprised to find out how many are actually attempting to break in once the plugin is installed.