A Mac developer has posted a tool that detects a Flashback malware infection on Apple's computers. The tiny tool -- it's just a 38KB download -- was created by Juan Leon, a software engineer at Garmin International, the Kansas-based company best known for its GPS devices. 

Ars Technica first reported on Leon's FlashBack Checker. The tool spots the malware by automating a tedious process first described by security firm F-Secure last month. F-Secure's procedure required entering multiple commands in Terminal, the Mac OS X command line utility. (More below) 

When Flashback Checker is run, it displays "No signs of infection were found" or provides additional information if it does detect changes the malware has made to the Mac.

Unlucky users can scrub Flashback from their machines using commercial security software -- both French vendor Intego and Finland's F-Secure offer free 30-day trials to their Mac antivirus products -- or use the complex instructions posted by the latter here.

According to Dr. Web, the Russian security company that was the first firm to quantify Flashback infections, nearly 2% of all Macs have been hit by the malware. (Apple has tried to shut down one of the domains of Dr. Web). 

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.

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

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

Juan Leon's free tool automates a Flashback detection process that requires users to enter several commands in Mac OS X's Terminal app.

What can you do to protect your Mac from security threats? Read our article here.