More than half a million Macs are infected with the Flashback Trojan, a malware package designed to steal personal information, according to a Russian antivirus company. The company -- Dr. Web -- originally reported today that 550,000 Macintosh computers were infected by the growing Mac botnet. But later in the day, Dr. Web malware analyst Sorokin Ivan announced on Twitter that the number of Macs infected with Flashback had increased to 600,000, with 274 of those based in Cupertino, Calif. More than half of the Macs infected are in the United States (57 percent), while another 20 percent are in Canada, Dr. Web said. The malware was initially found in September 2011 masquerading as a fake Adobe Flash Player plug-in installer, but in the past few months it has evolved to exploiting Java vulnerabilities to target Mac systems. A new variant that surfaced over the weekend appears to be taking advantage of Java vulnerability for which Apple released a patch yesterday. Read more here.