Things get worse because the flashback trojan was written in an unknown language, and it does not need to know your password to access you MAC OS system . But don't worry too much, you can check whether your Mac is infected, if so than you can remove it.
How to check whether your Mac is infected by FlashBack Trojan.
1. From Utilities folder, then open Terminal.
2. Then, once you're in, follow these easy steps to detection:
3. Within it, then type the command below in Terminal
defaults read /Applications/Safari.app/Contents/Info LSEnvironment
4. Make a note of the value, DYLD_INSERT_LIBRARIES
5. Continue to the step 6 if you receive this error message:
The domain/default pair of (/Applications/Safari.app/Contents/Info, LSEnvironment) does not exist
6. Type this command in Terminal:
defaults read ~/.MacOSX/environment DYLD_INSERT_LIBRARIES
7. Take note of the result. Your system is already clean of this variant if you got an error message similar to the following:
"The domain/default pair of (/Users/joe/.MacOSX/environment, DYLD_INSERT_LIBRARIES) does not exist"
If you get variant "does not exist" after running the commands from the above steps, means your MAC is clean or not infected. If the command gives you result other than that, you can head to F-secure to deal with it.
Want to easier method? You can download FlashbackChecker app to check Trojan Downloader Flashback on Mac.