"This ultimately results in lost revenue for Google and untold sums of money for the Flashback gang," Symantec wrote. Since Flashback infected hundreds of thousands of users, "this figure could sharply rise to the order of $10,000 per day," Symantec wrote.

Flashback infected Apple computers using a critical vulnerability in Java, which Apple patched in early April about seven weeks after the issue was disclosed. In the interim, upwards of 800,000 computers were believed to have been infected. Apple released a special Flashback removal tool on April 13.