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.
http://support.apple.com/kb/HT5934
http://support.apple.com/kb/HT5880
http://secunia.com/advisories/54886
http://lists.apple.com/archives/security-announce/2013/Sep/msg00006.html
http://lists.apple.com/archives/security-announce/2013/Sep/msg00002.html