A must read from weblogtools Collection titled: “Why You Should Never Search For Free WordPress Themes in Google or Anywhere Else”. They explain and warn users to get free WordPress themes from trusted sources like WordPress.org. You can also get themes from the designer’s personal sites like WpThemesPlanet.com All the designers from WordPress.org are trusted. The most dangerous themes are known Premium themes that are listed for free download at bogus blogs. For example there are WooThemes Premium themes in many different sites listed for free download. Themes that you are supposed to pay for. They usually embed some malicious code into the themes and many times they encode this bad code using base64 decode.
Siobhan on WPMU.org has a nicely illustrated, researched and explained article on why users should never search for “Free WordPress Themes” in Google or any other search engine. Not enough can be said to avoid the malicious theme hawkers on the Internet and I appreciate the work and the explanation.
The problem is that most users, who are new to the ways of WordPress, will still use Google to search for themes and will download the first link that provides them with a free theme that catches their fancy. I would go so far as to say that somewhat knowledgeable users might still be tempted to ignore any possible bad effects from these themes; e.g. users continue to flock to sites that provide collections of serial numbers online in spite of being riddled with porn and adware. My opinion is that there are two ways to solve the problem or at least throttle down the preponderance of malicious themes installed on hapless WordPress blogs. Both options come with their pros and cons but one is a resolution closer to home.