If you’re running a WordPress site, now would be a good time to ensure you are using very strong passwords and to make sure your username is not “admin.” According to reports from HostGator and CloudFlare, there is currently a significant attack being launched at WordPress blogs across the Internet. For the most part, this is a brute-force dictionary-based attack that aim to find the password for the ‘admin’ account that every WordPress site sets up by default.

HostGator’s analysis found that this is a well-organized and very distributed attack. The company believes that about 90,000 IP addresses are currently involved. CloudFlare, its founder and CEO Matthew Prince told me earlier today, thinks the hackers control about 100,000 bots. As for the scope of the attack, Prince says that CloudFlare saw attacks on virtually every WordPress site on its network.

Read the whole article here :
http://techcrunch.com/2013/04/12/hackers-point-large-botnet-at-wordpress-sites-to-steal-admin-passwords-and-gain-server-access/