The IPSec implementation in Apple Mac OS X before 10.8.5, when Hybrid Auth is used, does not verify X.509 certificates from security gateways, which allows man-in-the-middle attackers to spoof security gateways and obtain sensitive information via a crafted certificate.
Apple Security Advisory 2013-09-12-1 - OS X Mountain Lion v10.8.5 and Security Update 2013-004 is now available and addresses Apache issues, BIND issues, ClamAV issues, and more.