An online hacker group associated with Anonymous claims to have posted 1 million Apple Unique Device Identifiers (UDIDs) by breaching FBI security.

A UDID is the unique string of numbers that identifies each iOS device, formerly used by developers to track their app installations across Apple's user base.

In all, AntiSec claims to have obtained more than 12 million UDIDs, including user names, addresses, and notification tokens from a laptop used by an FBI agent. In a missive posted to Pastebin, the hacking group explains how it obtained the data from an FBI agent's laptop:

During the second week of March 2012, a Dell Vostro notebook, used by Supervisor Special Agent Christopher K. Stangl from FBI Regional Cyber Action Team and New York FBI Office Evidence Response Team was breached using the AtomicReferenceArray vulnerability on Java, during the shell session some files were downloaded from his Desktop folder one of them with the name of "NCFTA_iOS_devices_intel.csv" turned to be a list of 12,367,232 Apple iOS devices including Unique Device Identifiers (UDID), user names, name of device, type of device, Apple Push Notification Service tokens, zipcodes, cellphone numbers, addresses, etc. the personal details fields referring to people appears many times empty leaving the whole list incompleted on many parts. no other file on the same folder makes mention about this list or its purpose.

Although Apple has already said it would begin restricting developer access to the identifiers, the Pastebin post says the group posted the data out of suspicion the FBI was using the UDIDs for nefarious purposes, such has people tracking, as well as to protest the use of UDIDs in general.

We always thought it was a really bad idea. that hardware coded IDs for devices concept should be erradicated from any device on the market in the future.

Even though it says it has more than 12 million UDIDs, AntiSec says it settled on posting only 1 million, trimming out personal information such as full names, cell numbers, and addresses.

We left those main columns we consider enough to help a significant amount of users to look if their devices are listed there or not. the DevTokens are included for those mobile hackers who could figure out some use from the dataset.

CNET has contacted Apple and the FBI for comment and will update this report when we learn more.