Google has been able to detect a large number of computers infected with a specific piece of malware. If you go to Google and do a search (any word will do) right now, check to see whether you get a “Your computer appears to be infected” warning at the top of the search results. If you see the message, you need to clean up the infection from your machine.
As we work to protect our users and their information, we sometimes discover unusual patterns of activity. Recently, we found some unusual search traffic while performing routine maintenance on one of our data centers. After collaborating with security engineers at several companies that were sending this modified traffic, we determined that the computers exhibiting this behavior were infected with a particular strain of malicious software, or “malware.†As a result of this discovery, today some people will see a prominent notification at the top of their Google web search results:
This particular malware causes infected computers to send traffic to Google through a small number of intermediary servers called “proxies.†We hope that by taking steps to notify users whose traffic is coming through these proxies, we can help them update their antivirus software and remove the infections.
You can run a system scan on your computer yourself by following the steps mentioned here. This is malware that’s specific to Windows.