Two months ago, a new variant of the Flashback Trojan started exploiting a security hole in Java to silently infect Mac OS X machines. Apple has since patched Java, but this was only on April 3rd. More than 600,000 Macs are currently infected with the Flashback Trojan, which steals your user names and passwords to popular websites by monitoring your network traffic.
To know if you were infected, run these commands:
defaults read /Applications/Safari.app/Contents/Info LSEnvironment defaults read ~/.MacOSX/environment DYLD_INSERT_LIBRARIES
If both give an error/notice that ends with “… does not exist”, you’re safe.