Wordfence is a powerful WordPress plugin which protects your website from Distributed Denial of Service (DDoS) attacks, malicious web crawlers and other types of attack techniques commonly used by hackers, script kiddies etc. The plugin can also scan your entire installation in real time for various types of existing as well as new vulnerabilities like Heartbleed etc.
CloudFlare offers a free security plugin for your self-hosted installation of WordPress, which make use of spam database hosted and maintained by Project Honey Pot to protect your blog from hackers, attackers and malicious IP addresses.
In cryptography, Brute force is a sophisticated attack technique, which is used to guess the passphrase of various types of online as well as offline accounts. This technique is generally utilized to guess the passwords which are shorter in length. When it comes to guessing lengthy passwords, a hacker may use a more sophisticated attack technique known as Dictionary Attack, because brute force takes a whole lot of time (in months and sometimes in years) in guessing lengthy passwords. Keep in mind that no matter how much time brute force takes to guess a password, chances are very high that it will always succeed, while for dictionary attack there is no guarantee of success!
Login LockDown allows you to limit total number of access attempts to your blog’s dashboard from a particular IP address or an IP range. The plugin is capable of recording all the IP addresses, which are constantly trying to get into your dashboard, but all their login attempts are continuously failing. It can also record the time stamp for each failed login attempt.