Intego is warning Mac users of a Trojan Horse on Mac OS X. Named OSX.RSPlug.A, it masquerades as a quicktime plugin that needs to be downloaded when watching porn. It then changes the DNS address on the users computer which points to more porn. MacOSXHints as a quick tutorial on removing the Trojan Horse.

Intego has warned about other malware on the Mac, only to be accused of overblowing the situation. The other warnings were more about theoretical attacks, this appears to be real. It's only showing up on porn sites now, but it could be a prototype for use in wider distribution later.

This may just be the beginning of more attacks on the Mac OS as it becomes more popular.