But the new detection API gave these applications direct access to information in the OS. In theory, the iOS device then "confesses" that it has been jailbroken, thereby triggering automatic responses such as alerting the helpdesk or shutting down access to corporate Exchange Server e-mail.
"We used it when it was available, but as an adjunct," says Joe Owen, vice president of engineering at Sybase, which offers the Afaria device management software. "I'm not sure what motivated their removing that....I've not had anyone [at enterprise customer sites] talk to me about this API being present or being removed."
In practice, Apple's idea of using an API-based query turned out to be much more complicated than it sounds. "It's an interesting concept - asking the OS to tell you if it has been compromised," Owen says. "Because a smart attacker might first change that very part of the OS. Jailbreaks often get better and better at disguising the fact that anything has been compromised."
When that happens, the API in effect either lies about or is simply unaware of the jailbreak.
"[I]t may be feasible to detect jailbreaks of a specific version or type, but they will still be trapped in the cat and mouse game they play with jailbreakers," says Jeremy Allen, principal consultant with Intrepidus Group, a security consulting firm. "Whatever they add [in the OS] to detect the jailbreak, if it is to be queried from the iOS kernel, it must be accessible and have the ability to be changed. Meaning, if it is going to be a useful detection method it can also be circumvented. It is a fairly intractable problem to solve 100%."
For a group of computer-savvy end users, jailbreaking is an unalloyed benefit, not to mention a civil right, letting them load any applications they wish. But for enterprise IT, jailbroken iOS devices create a serious security threat.
"When jailbreaking and or rooting a [mobile] device, the goal is to circumvent or disable the pieces of the OS and platform that keep applications in a sandbox and running with limited privileges," Allen wrote in a recent blogpost on trusting mobile platforms. "These devices could be difficult, or even impossible, to enforce security policy on as the user can trivially circumvent the policy enforcement without the management servers being aware of it."