An ingenious piece of malware manages to hide so well inside a WordPress website. Malware is clever about how it stores the spam content on the site and how it operates to inject the content into the original response sent by WordPress. At the time of this writing, there are already 173 hacked sites based on this PublicWWW search. The malware has two distinct purposes: Add hidden links for indexing by search engines and redirect site visitors to spam content. It then hijacks the WordPress connection while the site is still processing its response.”]
Source: https://blog.sucuri.net/2018/12/clever-seo-spam-injection.html