Microsoft researchers uncovered a new piece of Mac malware that can install remote-control backdoors on compromised machines. Other researchers questioned whether it was a credible threat at this time.
Microsoft researchers came across the backdoor, named Olyx, in a package which contained a different Windows malware, according to a July 25 post on the Microsoft Malware Protection Center blog. This Mac backdoor appears to be very similar to the Gh0st RAT malware that targeted older Windows systems back in 2009.
The package contained a Mac binary file that "installs and runs in the background without root or administrator privileges," wrote Meths Ferrer, a threat researcher for MMPC based in Melbourne, Australia.
Olyx pretends to be a Google application support file by creating a Google folder in the Application Support directory. The backdoor runs only once when the user logs in, so on systems with multiple user accounts, it will execute once for every account. When launched, it opens a remote connection with a South Korean IP address. With the connection in place, a remote attacker can upload, download and navigate through files on the compromised machine, according to Ferrer.
Mac security vendor Intego was dismissive of Microsoft's discovery, noting that its researchers had "spotted this backdoor some time ago" and updated its malware definitions for its VirusBarrier antivirus software on June 30. Olyx also showed up in Kaspersky Lab's June Monthly Malware Statistics report.
"There is little threat to this malware, as it is not found in the wild in any form that can be installed on Macs," Intego said on its Mac Security blog.
A backdoor on its own is fairly harmless. It must either be manually installed by a user who was tricked into running the file or be bundled with other malware before it can infect the system. Olyx was not well-designed and can't be easily installed on user machines to compromise them, so it's not a real threat, Intego said.
"We don't publicize such malware by issuing security alerts, because the threat is not serious enough," Intego said.
Olyx is very different from the MacDefender fake antivirus that scammed users in May. MacDefender used various social engineering tricks to trick users into downloading the software and then handing over their credit card numbers.
Despite the low threat, Intego proactively updated its antivirus definitions so that if Olyx ever packaged into an "effective payload" to infect users, VirusBarrier users will already be protected, the company said.
Mac-based threats remain relatively obscure and even with Mac Defender on the scene, Mac malware accounts for a minuscule fraction of total malware. It's easy to get worked up about new and sophisticated attacks as they are discovered, but not all of them become actual threats, said Tal Be'ery, a member of Imperva's Application Defense Center. As for reports of researcher Charlie Miller manipulating the micro-chips on a Mac laptop battery last week, Be'ery said, "Cool? Yeah! Sophisticated? Absolutely! Practical? Not really."
"No matter how obscure and fun an attack sounds, we need to focus on the real threats," Be'ery said.