Chapter 3:
iOS
KNOW YOUR iPHONE iOS has an interesting history, and it helps to understand more about it when learning to hack the platform. Development on what would later become iOS began many moons ago, in the mid-1980s at NeXT, Inc. Steve Jobs, having recently left Apple, founded NeXT. NeXT developed a line of higher-end workstations intended for use in educational and other nonconsumer markets. NeXT chose to produce its own operating system, originally named NeXTSTEP. NeXTSTEP was developed in large part by combining open source software with internally developed code. The base operating system was derived primarily from Carnegie Mellon University’s Mach kernel, with some functionality borrowed from BSD Unix. An interesting decision was made regarding the programming language of choice for developing applications for the platform. NeXT chose to adopt the Objective-C programming language and provided most of their programming interfaces for the platform in this language. At the time, it was a break from convention, as C was the predominant programming language for application development on other platforms up to that point. Thus, application development for NeXTSTEP typically consisted of Objective-C programming, leveraging extensive class libraries provided by NeXT. In 1996, Apple purchased NeXT and, with that purchase, came the NeXTSTEP operating system (by that time, renamed to OPENSTEP). NeXTSTEP was then chosen as the basis for a next-generation operating system to replace the aging Mac OS “classic.” In a prerelease version of the new platform, codenamed Rhapsody, the interface was modified to adopt Mac OS 9 styling. This styling was eventually replaced with what would become the UI for Mac OS X (codenamed Aqua). Along with UI changes, work on the operating system and bundled applications continued, and on March 24, 2001, Apple publicly released Mac OS X, their next-generation operating system, to the world. Six years later, in 2007, Apple boldly entered into the mobile phone market with the introduction of the iPhone. The iPhone, an exciting new smartphone, introduced many novel features, including industry-leading design of the phone itself as well as a new mobile operating system known initially as iPhone OS. iPhone OS, later renamed somewhat controversially to iOS (owing to its similarity to Cisco’s Internetwork Operating System, or IOS), is derived from the NeXTSTEP/Mac OS X family and is more or less a pared-down fork of Mac OS X. The kernel remains Mach/BSD-based with a similar programming model, and the application programming model remains Objective-C based with heavy dependence on class libraries provided by Apple. Following the release of the iPhone, several additional devices powered by iOS were released by Apple, including the iPod Touch 1G (2007), Apple TV (2007), and iPad (2010) and iPad mini (2012). The iPod Touch and iPad are highly similar to the iPhone in terms of their internals (both hardware and software). Apple TV varies a bit from its sister products in that it is more of an embedded device intended for use in the home rather than a mobile device. However, Apple TV still runs iOS and functions roughly the same (the most notable differences being the user interface and lack of official support for installation and execution of apps). From a security perspective, all of this is mentioned to provide some context, or some hints in terms of where the focus tends to be when attempting to attack or provide
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