There are many shared hosting companies that are pulling there hair out due to increase traffic to WordPress websites.
A well trusted company such as HEART INTERNET for example have put this message up:-
Current System Status
Access to WordPress Admin
Fri, 12 Apr 2013 13:07:24 +0100
We are seeing increased traffic to a large number of WordPress sites on our shared hosting platform. The attack is not unique to ourselves and is affecting many hosting providers worldwide. Many providers have blocked access to the Admin area of WordPress altogether, however we do not want to take this approach as it will also prevent you from administering your own website. Instead, when accessing your WordPress Admin Area you may find that you are prompted for a username and password not previously required. The credentials for this login are:
As soon as normal service is resumed, this prompt will be removed and the above credentials will no longer be required. We appreciate your patience during this time, and we will update this page once this has been resolved.
Worldwide Brute-Force Attack
Go Daddy have put this message up:-
Web Hosting April 11, 2013 at 11:06 AM
We continue to mitigate the Internet-wide attack, but customers should be able to access their admin pages. If you need to strengthen your password, we recommend referring to x.co/strongpass for guidance. Thanks for your patience.We are aware of an ongoing, industry-wide attack attempting to gain access to customers’ websites. While we mitigate it, you might not have access to admin pages for Joomla! or WordPress. Your site, however, will remain online. To keep your site and your information secure, we recommend changing your password when you regain access to your site.
What Go Daddy Are Doing
Our Security team continues to identify these attacks, down to the IP address, and block anything that looks malicious. Additionally, we’ve installed new features on every single one of our thousands of servers to block these bad actors more quickly.
What You Can Do
Regardless of whether you use WordPress or Joomla! for your website, this worldwide attack could affect you. That’s why it’s imperative that you use strong passwords.
We all know that “password123” is not a wise idea for a password, but neither are dictionary words, your dog’s name, or the name of the street you live on. Attackers have libraries of the most common passwords, and use those lists in attacks like we’re experiencing.
The tougher and more sophisticated your password, the more difficult it will be for an attacker to gain access