We've been suffering from some very nasty black hat seo. In Google's index, our pages show exteal links to various pharmaceutical websites, but our actual live pages don't show them. It seems as though only certain user-agents see the malicious links. Setting up Screaming Frog SEO crawler using the Googlebot user agent also sees the malicious links.
Any idea what could have caused this or how this can be stopped? We scaed all files on our webserver and couldn't find any of malicious links. We've changed our FTP and CMS passwords, is there anything else we can do?
Thanks in advance!