Apple Inc. has pushed out an automatic security update for Macintosh OS X computers to address a critical security issue that was too risky to wait for users to patch after seeking their prior approval. The security hole in NTP would give hackers ability to turn users’ Macs into DDoS zombies. NTP is a global way of synchronising time over a network, and because of its link to networks it has previously been exploited by hackers a number of times. The vulnerability affects dozens of technology companies’ products including Apple’s. The company recommends that all users apply this patch “as soon as possible”
Source: https://thehackernews.com/2014/12/Apple-Mac-Security-Patch.html