Google plans today to begin warning Internet users if their computers show telltale signs of being infected with the DNSChanger Trojan. The company estimates that more than 500,000 systems remain infected with the malware, despite a looming deadline that threatens to quarantine the sick computers from the rest of the Internet.
Security experts won court approval last year to seize control of the infrastucture that powered the search-hijacking Trojan in a bid to help users clean up infections. But a court-imposed deadline to power down that infrastructure will sever Internet access for PCs that are not rid of the malware before July 9, 2012.
The company said the warning (pictured above) will appear only when a user with an infected system visits a Google search results property (google.com, google.co.uk, etc.), and will include the message, “Your computer appears to be infected.” Google security engineer Damian Menscher said the company expects to notify approximately a half-million users in the first week of the notices.
“In general we want to notify users [of malware infections] anytime we are capable of doing so, but the fact that we don’t do this more often is really just because it’s hard to come across cases where we can do it this accurately,” Menscher said. “In many cases we only have maybe a 90 percent confidence that someone is infected, and the false positive rate of 10 percent is simply too high to be feasible. But in this case we can be essentially certain that someone is infected.”