The App Store process in CommerceKit Framework in Apple OS X before 10.10.2 places Apple ID credentials in App Store logs, which allows local users to obtain sensitive information by reading a file.
http://www.securitytracker.com/id/1031650
http://support.apple.com/HT204244
http://lists.apple.com/archives/security-announce/2015/Jan/msg00003.html