Intego, a company that deals exclusively in Mac security, announced in a press release that it's "discovered a new variant of a malware for Mac, called HellRTS, which, when installed on computers running Mac OS X, opens a backdoor that allows remote users to take control of infected Macs and perform actions on them."
It's possible that HellRTS is about to become rather common, too, given that Intego found it being distributed on more than a couple online forums.
The good news for Mac users/Maiffret critics is that Intego hasn't yet encountered a single HellRTS-infected Mac in the wild, so it's possible that the malware won't ever represent any sort of real threat.
One last note: Maiffret doesn't appear to bear even the faintest connection to Intego, so there's no need for anyone to worry too much about the timing of his comment and Intego's apparent substantiation of it.