Attackers are gaming Google’s page ranking-algorithms using a new search poisoning method that circumvents cloaking-detection mechanisms using PDF files. Discovered by researchers from Sophos, the technique is now being found in use within hundreds of thousands of unique PDF documents per day. Google has built in protections within its algorithm to make it harder to cloak sites via fake HTML pages, but now attackers have pivoted by using phony PDFs instead. Once that’s accomplished, attackers are able to redirect users clicking into the PDF to a different site.”]
Source: https://www.darkreading.com/cloud/new-google-search-poisoning-method-cloaks-with-pdf-docs