Security firms Sophos, and F-Secure have both noted that there's a new piece of malware floating round that is targeting Mac, Windows and Linux users all at the same time. The malware pretends to be a required add-on.
Of course, it's not, and in reality its victims are opening up a Java archive file, which then detects the platform the victim is using, before connecting to a remote server to fetch the additional code, creating a back door for hackers. THe Mac-based malware is identified by F-Secure is "Backdoor:OSX/GetShell.A."
What makes this new piece of malware stand out from the very crowded sea of infectious crap that is out there is that this particular code is targeting multiple platforms at once. Most hackers usually stick to attacking Windows, or OS X. Hopefully it doesn't get too much more widespread, and people continue to educate themselves on what to, and what not to, click, open or accept.