MacInTouch is currently hosting animated discussion on what could be the first real malware to afflict Mac OS X, Opener. Moreover, readers' informal investigations seem to have tracked this aberration to the Macintosh Underground, a loose a affiliation of Mac-based hackers (ie associated with more sites than just the one linked here).
To date, Opener appears to be purposed to collect information, passwords and set up a back door—ie it's a Trojan. A direct first-hand account of an infection doesn't indicate file destruction, but that could change literally over night in the wrong hands.
As of this writing, where this attack originated and how it succeeded aren't known.
