Recently, Apple introduced the system of Developer ID to enhance the security of Mac. Now Apple is enforcing the new system of sandboxing to make Mac security, stronger.
Apple has released a security update for Leopard. Apart from this update, Apple has also released a Flashback removal tool for that version of the OS.
Apple has sent email to developers in its various programs to go ahead and get their applications ready with the Developer ID program. This program is basically a new form of certifying apps that run on Mac or any iOS device.
Last week, along with the OS X 10.7.3 update (which later turned out to be having bug), Apple had released Security Update 2012-001 for those Mac users who are skeptical about Lion and prefer OS X 10.6 Snow Leopard over Lion.