What is it
This framework is for fuzzing OSX kernel vulnerability based on passive inline hook mechanism in kernel mode.
Basically, it is a typical kernel driver which inline-hooked import API related to IOKit framework and kernel service.
You could collect kernel dump and reproduce the vulnerability if kernel crash happens.
You can follow my twitter: @Flyic (of moony li)to more info in detail.
The source code is to be released after our presentation "Active fuzzing as complementary for passive fuzzing" on PacSec 2016 in Tokyo(10.26/10.27)
The passive fuzzing framework is based on “the_flying_circus” rootkit for OSX by fG! Special thanks to fG!
Requirement for running
In principle, the passive fuzzing framework could support popular OSX version for Mac Pro,Air.
As our experience, there kernel revision from 10.11 to 10.11.6 cause little or non interference to passive fuzzing.
The framework has been tested on 10.11.6 MacPro with KDK_10.11.6_15G31.kdk.
- How to use
Running the kernel driver would cause sudden kernel crash so as to lose all your data. Take your own risk to use this kernel driver.
3.1 Quick Start
If you want to try the passive fuzz just for fun, please quick try like this: a. Load driver for quick passive fuzz sh-3.2# chown -R root:wheel ./quick-pasive_kernel_fuzz.kext sh-3.2# kextutil ./quick-pasive_kernel_fuzz.kext b. quick-pasive_kernel_fuzz would appear in kernel module sh-3.2# kextstat You would see the driver appears in the kernel module list. However,
3.2 Full Start with ThunderBolt wire
This start guide is suitable for all Mac OSX machine(e.g. MacPro, MacAir, Mac Mini). This solution require for another debugger OSX machine and extra ThunderBolt wire. 1. On target(or debugee) OSX machine: a. Prepare KDK and nvram I. Download KDK_10.11.6_15G31.kdk (take this KDK for example) and install on your Mac machine II. Copy kernel.development to system folder and synchronise kernel cache sh-3.2# cp -fr /Library/Developer/KDKs/KDK_10.11.6_15G31.kdk/System/Library/Kernels/kernel.development* /System/Library/Kernels/ sh-3.2# kextcache -invalid / sh-3.2# reboot III. Set up boot-args for debugging sh-3.2# nvram boot-args="debug=0x566 kdp_match_name=firewire fwkdp=0x8000 pmuflags=1 kext-dev-mode=1 -v" sh-3.2# reboot b. Load driver for passive fuzz sh-3.2# chown -R root:wheel ./pasive_kernel_fuzz.kext sh-3.2# kextutil ./pasive_kernel_fuzz.kext c. Proberbly your Mac Machine would kernel crash waiting for further deubugging 2. On debugger OSX machine: IMPORTANT TIP: Always keep the ThunderBolt connected with the two machine always because plug and play (recognize) is NOT supported for the crashed kernel. a. Prepare KDK I. Download KDK_10.11.6_15G31.kdk (take this KDK for example) and install on your Mac machine This step is not necessary but strongly recommented. When lldb in furthur following steps, lldb would match *.dSYM symbol file between debugee machine and debugger machine. Otherwise, symbol info would NOT be shown during your debugging. b. Debug the crashed target machine I. Launch fwkdp service flyic-pro:pasive_kernel_fuzz.kext root1$ fwkdp II. lldb debug sh-3.2# cd /Library/Developer/KDKs/KDK_10.11.6_15G31.kdk/System/Library/Kernels sh-3.2# lldb ./kernel.development (lldb) kdp-remote localhost The debugger would wait until the target machine crashes, and then you can type any command for debugging including collect core dump file.
3.3 Full Start with Wire LAN
Because only lagecy OSX machine support Wire LAN (e.g. Old MacMini), this kind of debugging is not popular. To be done
Ever collected core dump files, lldb debug logs, poc and so forth (keep updating, about 100GB).
5.1 MacOS 10.12 MachO format parse error
process_kernel_mach_header(void *kernel_header, struct kernel_info *kinfo)
could not analyze the machO file format in 10.12 which may be different with 10.11 or before so as to cause kext load fail.