In case you are not aware there is an ongoing botnet attack on Wordpress and Joomla websites. It is a significant attack and is being documented by reliable sources. I'm not going to repeat that information here other than to raise the importance of being vigilant about good security practice and up-to-date with Wordpress installs and plugins.
You can read a good user-friendly account with links to the sources here at ithemes.
Please take the time to ensure you don't become a victim of these attacks.