SEO poisoning is on the rise and is currently being used by two well-known ransomware gangs Gootloader and SolarMarket to serve payloads on targets.

The practice is an attack method based on the optimization of websites using ‘black hat’ SEO techniques to place higher in Google search results.

According to security researchers in Menlo, the optimized pages appear in search results as PDFs that are clicked by users to download a document after clicking the prompt.

Clicking on the download button redirects users through a number of websites that ultimately drop a malicious payload.

Researchers also found that instead of having a malicious site instead, they hacked legitimate WordPress sites that has a good Google search ranking, and they do this by exploiting an undisclosed flaw in the “Formidable Forms” WordPress plugin.

Those using the above plugin are asked to upgrade to version 5.0.10 or higher.