Trojan Virus Has Infected 600K Macs, Firm Claims Virus may allow hackers to create 'botnet' from infected machines By Kevin Spak, Newser Staff Posted Apr 5, 2012 4:59 PM CDT 20 comments Comments A customer types on a MacBook laptop in this file photo. (Getty Images) (Newser) – Are you a smug Mac user who assumes you can't possibly get a virus? Well, think again. A Russian anti-virus firm believes that about 600,000 Macs around the world have been infected with the Flashback Trojan virus—and about half of those are expected to be in the US. The virus may allow cybercriminals to take over infected computers en masse and use them as a "botnet," the BBC reports. Don't panic yet, though; the firm says it hasn't actually observed any "malicious activity," and that it has "hijacked the botnet to take it out of criminals' hands." Apple released a security patch yesterday to combat the problem, but anyone who hasn't updated since is still at risk.