According to Dr. Web, the Russian security company that was the first firm to quantify Flashback infections, have been hit by the malware.

Dr. Web used a different technique to detect Flashback than Leon. Rather than examine the Mac itself, Dr. Web's tool compares the UUID (universally unique identifiers) of a machine to the list of UUIDs of infected Macs it compiled after commandeering a hacker command-and-control (C&C) server.

Flashback has been in circulation since last September, but only in the last several weeks has the malware been installed silently via "drive-by" attacks that rely on exploiting a just-patched vulnerability in Oracle's Java.

on April 3, or seven weeks after Oracle had patched the vulnerability for Windows and Linux users.

had been downloaded nearly 36,000 times from the github source code repository as of 4 p.m. ET Monday.