Apple today released OS X NTP Security Update for Yosemite, Mavericks, and Mountain Lion.
Install this update as soon as possible.
This update addresses a critical security issue with the software that provides the Network Time Protocol service on OS X, and is recommended for all users.
Apple digitally signs its software updates to ensure the authenticity of update packages. Software Update automatically verifies a package’s signature prior to installing the update. If you manually download an update package, you can verify the signature yourself to confirm that the package is authentic and complete. See this article for details on how to verify the authenticity of this download.
For more information on the security content of this update see http://support.apple.com/kb/HT1222
OS X NTP Security Update is available via Software Update.
OS X NTP Security Update is also available via manual download. More info and download links:
• OS X NTP Security Update: OS X Yosemite
• OS X NTP Security Update: OS X Mavericks
• OS X NTP Security Update: OS X Mountain Lion