Internet Storm Center researcher Bojan Zdrnja writes that the attackers are mostly targeting WordPress sites, and are injecting PHP code that generates pages with images based on highly-searched content. Google then indexes these pages, and the images show up on Google’s image search.
Image hack is widespread and effective
Image searchers can be redirected to these fake antivirus sites, thanks to Google displays images when clicked, Zdrnja wrote in a blog post this week. At least 5,000 sites have been compromised, and Google could be serving as many as 15 million hits a month to these malicious pages.
Russian security researcher Denis Sinegubko said that, in about 90 percent of the compromised image searches, results from malicious websites appear on the first page.
“The main problem is not that cybercrooks managed to seriously poison Google Image search results but the fact that many people do click on such results results and get exposed to malicious content,” Sinegubko wrote to the Unmask Parasites blog on Thursday.
Google says it is aware of the problem, and is making an effort to detect malicious pages. It would not detail its plans out of fear that attackers may adjust their methods to get around the company’s efforts. Sinegubko is also in the process of developing an add-on for Firefox that will alert users to these links.
Efforts are already underway to protect Google users on the web search side: Google added alerts to potentially hacked sites in December of last year, and Google’s Chrome browser blocks potentially dangerous downloads. For whatever reason, Google’s image search remains unprotected.
What can you do in the meantime to protect yourself if you feel that you have visited a malicious site via Google Images? Security experts recommend not trying to click your way out of it. Instead, quit the browser application using Ctrl-Alt-Delete.
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