Google today began warning more than a million Internet users that their computers are infected with a malicious program that hijacks search results and tries to scare users into purchasing fake antivirus software.
Google security engineer Damian Menscher said he discovered the monster network of hacked machines while conducting routine maintenance at a Google data center. Menscher said when Google takes a data center off-line, search traffic directed to that center is temporarily stopped. Unexpectedly, Menscher found that a data center recently taken off-line was still receiving thousands of requests per second.
Menscher dug further and discovered the source of the traffic: more than a million Microsoft Windows machines were infected with a strain of malware designed to hijack results when users search for keywords at Google.com and other major search engines. Ironically, the traffic wasn’t search traffic at all: The malware instructed host PCs to periodically ping a specific Google Internet address to check whether the systems were online.
Menscher said the malware apparently arrives on victim desktops as fake antivirus or “scareware” programs that use misleading warnings about security threats to trick people into purchasing worthless security software. He suspects that the fake AV program either ships with or later downloads the search hijacker component.