Improving Mac OS X security through gray box fuzzing technique

The kernel is the core of any operating system, and its security is of vital importance. A vulnerability, in any of its parts, compromises the whole system security model. Unprivileged users that find such vulnerabilities can easily crash the attacked system, or obtain administration privi- leges. In this paper we propose LynxFuzzer, a framework to test kernel extensions, i.e., the dynamically loadable com- ponents of Mac OS X kernel. To overcome the challenges posed by interacting with kernel-level software, LynxFuzzer includes a bare-metal hardware-assisted hypervisor, that al- lows to seamlessly inspect the state of a running kernel and its components. We implemented and evaluated LynxFuzzer on Mac OS X Mountain Lion and we obtained unexpected results: we indivuated 6 bugs in 17 kernel extensions we tested, thus proving the usefulness and eectiveness of our framework.