Apple - 2012

Hackers associating themselves with Anonymous claim to have obtained 12 million Apple Unique Device Identifiers (UDIDs) by hacking an FBI agent's laptop.  The hackers offered proof of the breach by posting over one million UDIDs. However, both Apple and the FBI are denying that an FBI agent would have access to that information and keep it on a laptop. The hack occurred in March. Apple replaced the types of identifiers the hackers appear to have obtained and will discontinue their use.