Though WordPress is by far one of the most secure content management systems (CMS) around, it's popularity makes it vulnerable to attacks. In fact, each day Google blacklists approximately 10,000 websites for suspicious activity, and you had better believe numerous WordPress websites are included on these lists.
Despite the obvious risks, many WordPress website owners fail to worry about their own site's security until something terrible happens. They are then left to deal with the aftermath of a hack attack or malware infection.