A Russian researcher named Sinegubko identified 4,358 WordPress blogs that combined popular images from other sites with so-called doorway pages that redirected visitors to a series of malicious sites.
He further wrote. “However the malicious redirects occur only when you click on Google Images search results, which proves that Google Images poisoning is the main goal of this black-hat SEO campaign.”
This is a major problem for sites using Wordpress and particularly for themes with embedded popular WordPress extension known as TimThumb.
So webmasters are advised to update their self-hosted wordpress installation and possibly look for weird codes on .htaccess file.
You may contact directly the researcher Sinegubko here. Just in case you have some information on this problem.
4,300+ compromised WordPress blogs poison
From the OneCebu archive, last updated February 10, 2014. Some details may have changed.