The Paharma Hack (or Blackhat SEO Spam Hack) is a very elaborated hack wich is often unobserved for the regular visitors - and website owners - because does an ingenious trick: present a different version of your site for the searchengine bots. The site, for a long period of time looks and behaves normally for the regular visitors. This attack is very interesting because it is not visible to the normal user and the spam (generally about Viagra, Nexium, Cialis, etc) only shows up if the user agent is from Google’s crawler (googlebot). Also, the infection is a bit tricky to remove and if not done properly will keep reappearing. It's one of nastiest hacks you might have. We recommend hiring a specialist to remove it, because generally the infection reappears in no time after the site is "cleaned".