libinfo in Apple iOS before 5.0.1 does not properly formulate domain-name queries, which allows remote attackers to obtain sensitive information via a crafted DNS hostname.
http://support.apple.com/kb/HT5130
http://support.apple.com/kb/HT5052
http://lists.apple.com/archives/security-announce/2012/Feb/msg00000.html
http://lists.apple.com/archives/Security-announce/2011/Nov/msg00001.html