Now a days due to hackers the blogs are been hacked by many of the hackers, the hactivism is going on allover the world.
hackers are not even wasting the time if they find lop holes in the websites and blogs. 
Bruteforce is an attack of an hackers where the hackers try the permutations and combinations of all passwords. In order to block the brute force attacks, we need to protect the blog by providing the strong passwords.

Strong password means, we must check the strength of an password and then keep the passwords on the run. To check the strength of passwords you can check from Passwordmeter .

For blogs like wordpress you can have plugins to secure your blog.
Login lock down: This is the mostly used plugin by most of the bloggers, this plugin blocks the ip address , if he attempts to bruteforce more that 5 permutations.

You can down this plugin for free in a wordpress directory.