Reprinted from TidBITS by permission; reuse governed by Creative Commons license BY-NC-ND 3.0. TidBITS has offered years of thoughtful commentary on Apple and Internet topics. For free email subscriptions and access to the entire TidBITS archive, visit http://www.tidbits.com/ OS X NTP Security Update (Yosemite, Mavericks, and Mountain Lion) Agen G. N. Schmitz Apple has released OS X NTP Security Updates for 10.10 Yosemite, 10.9 Mavericks, and 10.8 Mountain Lion to address a critical security issue with the software that provides the Network Time Protocol (NTP) service (which is used to keep a computer's internal clock synchronized with an external server). The updates are available via Software Update or via direct download from Apple's Support Downloads Web site. (All updates are free. For 10.10.1 [1]Yosemite, 1.9 MB; for 10.9.5 [2]Mavericks, 2.0 MB; for 10.8.5 [3]Mountain Lion, 2.1 MB) References 1. http://support.apple.com/kb/DL1782 2. http://support.apple.com/kb/DL1783 3. http://support.apple.com/kb/DL1781 .