The latest version, discovered on Monday by the Intego, has been labeled Flashback.S. It spreads using the same vulnerability as earlier versions, which means that it requires no password prompt to install itself on a targeted system.
There’s a new trick, too – this variant will delete files in ~/Library/Caches/Java/cache to remove traces of the trojan and prevent the recovery of samples by security firms (a ruse that,
obviously, hasn’t worked).
If you haven’t already updated your Mac (shame on you!), do so now. Apple’s updates to patch the flaw used by Flashback will work against this and all other know versions. The patch can be downloaded using the update service built in to OS X.
You can also protect yourself by installing an antivirus. According to Intego, Flashback does not even attempt to install itself on systems protected by certain software. This has been true since the original version and is likely an attempt to slow the detection of new variants.