Some 300,000 of the 600,000 Macs infected by the Flashback Trojan are located in the U.S., including 274 in Cuppertino, Apple's hometown in Silicon Valley, according to Tweets from Ivan Sorokin, a malware analyst at Russian antivirus company Dr. Web.

Sorokin's disclosure earlier this week of a massive botnet comprised entirely of Macs is serving as a lightning rod for the community of a few hundred top virus hunters worldwide, some of whom would like to see Apple become more collaborative about defending the Internet against cybercriminals.

"Maybe Apple will feel a little of the pain their users are now feeling and get serious about being more candid and perhaps more revealing in their patch release notifications," says Paul Henry, security and forensic analyst at network security company Lumension.