Apple Releases Two Mac OS X 10.5 Leopard Security Updates
While Apple only currently supports the last two versions of its operating system - 10.7 and 10.6 - the company has issued two security updates for Mac OS X 10.5 Leopard, showing just how much of an issue the Flashback malware is.
http://www.intego.com/mac-security-blog/apple-releases-two-mac-os-x-10-5-leopard-security-updates/