The file switch trick

Replacing PDFs with dodgy Flash files has become a new cybercriminal tactic.

Cybercrooks have developed a new technique for manipulating search engine results in order to promote the crud they sell, such as scareware packages.

Hackers first place benign PDF files on web pages they are seeking to promote, before replacing these documents with booby-trapped Flash files once a new site has been indexed.

Source: The Register.