There is new trouble in WordPress World, according to a report issued this week by Sucuri, the internet security experts (you can always run a free assessment of your website on their website). Read about the exploit here, and be certain to pay attention to any unusual activity at your site.
Among the proactive measures you can take is to see if your web host offers Sitelock® or similar security protection, and I have found the Wordfence plug-in very helpful to be aware of brute force attacks, new files added to your site, and other activity that could be suspicious.
As with any WordPress vulnerability, the best practice is to ensure you are running current themes, plug-ins and the WordPress software itself. If you no longer use a page or a plug-in, get rid of it.