Apple just released a patch for a “critical security issue” on Mac OS X that has to do with how the company’s operating system handles the Network Time Protocol or NTP. The vulnerability, which was first disclosed on Friday, allows an attacker to execute arbitrary code by sending a vulnerable computer a specially-crafted packet of information.
In other words, it’s bad news, which is why Apple is telling its users to install the patch as soon as possible.
Installing the patch is painless. It’s a 1.4 MB download that installs almost instantaneously and doesn’t require users to restart their machines. Seriously, just do it right now by opening up the Mac App Store, clicking on the Updates tab, and hitting update next to the OS X NTP Update line item. Computers running OS X Mountain Lion, Mavericks and Yosemite are all vulnerable.
An Apple Knowledge Base post explaining the content of the update can be found here.