Well: If it's just a scam like the one from your symantec link, I'm not worried. Would you open an application that someone you don't know sends you? Well: I wouldn't. And unless this was _directly_ targetted at my person (i.e. with a sender I know and a subject I'm interested in and it looking and feeling - i.e. sizewise - like something I might WANT to run), I just wouldn't run it on my Mac.
This is VERY different from how some trojans work on Windows...
Mac user since 1987. Running Mac OS X 10.8 Mountain Lion on a MacBook Air 11" & an iMac 27" and whatever's newest for my iPhone 4s, iPad 3 and AppleTV 2.
Apple Certified System Administrator 10.6, Apple Sales Professional 2008-2011, Apple Certified Mac Technician.