Sybase suggested that Apple may have dropped the API because jailbreakers could modify the system to disguise the fact that it had been compromised. An individual could decide the added functionality is worth the risk, but corporations have legal obligation to secure certain kinds of information, and otherwise have reason to secure mobile devices from hacking attempts. But removing those security features also make iPhones more vulnerable to malware and data theft. Jailbreaking an iPhone or other iOS device removes the built-in security features in order to run non-App Store software, use the device on other mobile networks (also known as 'unlocking'), or customize the user interface. Apple's own API offered a simplified way to merely ask the system if it was jailbroken and get a yes/no response. MDM software vendors such as Sybase already used their own methods for detecting jailbreaks, since jailbroken devices can represent a significant security risk. In fact, the detection API was introduced along with a series of APIs designed to improve device management for enterprise deployment. However, such a move would run counter to a Copyright Office ruling that jailbraking was essentially a legal activity. Word of a jailbreak detection API appearing in iOS 4.0, combined with the publication of a patent application for disabling an iPhone when an 'unauthorized user' is detected, originally stirred fears that Apple might be looking to automatically disable iPhones that were jailbroken. Third-party developers of mobile device management software told Network World that the API no longer works in iOS 4.2.1, though Apple never warned that it was being deprecated. Apple has apparently dropped access to a jailbreak detection API first added to iOS 4.0 this past summer.

Iphone jailbreak detection