I thought this was interesting:
If you end up downloading the trojan and entering your password it checks for the following:
If any of these are found, the malware will skip the rest of its routine and proceed to delete itself
even If you do not enter your password it attempts to install anyway, checking for the following applications:
/Applications/Microsoft Office 2008
/Applications/Microsoft Office 2011
If any of these are found, the malware again skips the rest of its routine and proceeds to delete itself, presumably to avoid infecting a system that has an incompatible application installed. Taken from F-Secure: http://www.f-secure.com/v-descs/trojan-downloader_osx_flashback_i.shtml
Very Strange logic here, at least the second case where the user doesn't enter their password...how do these apps prevent this malware from carrying out its mission, I do not know.