I've been reading through lots of threads about hacked wordpress sites, but none of them is exactly like my case. This is my situation:
I have a WordPress 3.5.1 with "Woocommerce" and "Registered users only" plugins installed. It has the " Discourage search engines from indexing this site" enabled so it doesn't appear on Google or other search engines, so it shouldn't be SEO/Spam attractive. It is a client-only reservated area.
Everything works right but sporadically when you hit a link it redirects you to a Spam Ad, in the same window, so clients would have to go back in the browser to keep on shopping.
I have erased all the wordpress installation, reinstalled it, and I'm reinstalling all plugins again with no result. I have also changed all the admin and FTP passwords... And I can't find any strange file where could be the hack.
Any suggestions or some help link?
Thank you in advance,