Difference between mbo and mbe pdf

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Difference between mbo and mbe pdf Mac OS X Kernel Rootkits ::. Everything else is too old and outdated.

8000839818 D _nsysent The location of sysent can be found by disassembling the kernel and using one of the three functions that reference it: – unix_syscall – unix_syscall64 – unix_syscall_return For 10. 2 the sysent pointer will be located at 0xFFFFFF80008000D0 and the table located at 0xFFFFFF8000855840. Landon’s formula does not apply here. 8000846ed8 D _nsysent And sysent located at 0xFFFFFF8000842A40. This confirms Apple moving around the pointer between different releases. Notice that all previous values are from kernel at disk so no kernel ASLR slide is included. The slide value will be disclosed whenever it is being used in the examples.

Another technique is described in The Mac Hacker’s Handbook , released in 2009 and targeting Leopard. 64 bits syscalls via the SYSCALL interface. 32 bits systems – it is used for 32 bits syscalls via SYSENTER. These are just a few possibilities to retrieve a valid address inside the running kernel and then find the start address of the kernel Mach-O header and sysent location. This alternative is easier and does not allocate new memory at the target. Do not forget to restore the original memory permissions. After so many words you are probably asking why not use copyout to copy from kernel to userland?

Chapter 7 of and Chapter 13 of thoroughly describe the execution process in case you are interested in every detail. The above diagram presents many places where we can modify the new process memory and its Mach-O header. As previously mentioned, when dyld gains control it will parse again the Mach-O header so our modification is guaranteed to be used if made before dyld’s control. Code signing does not kill immediately the process. The only puzzle piece left is which process should we use and how to kill it. Inside our new function we need to retrieve the necessary information to match the event we want to hide and return EINVAL or 0 in those cases. Macros exist to encode the integer for each available class.

Grep’ing XNU source code for BSDDBG_CODE will show where kdebug is implemented in all BSD related functions. What are the conclusions from all this? If only the sysent table function pointers are modified by the rootkit, DTrace will be unable to directly detect the rootkit using syscall provider. The modified pointer will be copied by DTrace and return to it. DTrace is blind to the original function because it does not exist anymore in the table, only inside our modified version.

We do not need to execute any additional command, o header so our modification is guaranteed to be used if made before dyld’s control. The zombie rootkit already gained control before this so there is no problem and we avoid to execute a kextunload command. Unix_syscall_return For 10. If only the sysent table function pointers are modified by the rootkit, the modified pointer will be copied by DTrace and return to it. 8000839818 D _nsysent The location of sysent can be found by disassembling the kernel and using one of the three functions that reference it:, released in 2009 and targeting Leopard. When dyld gains control it will parse again the Mach, to unload the original rootkit is extremely easy, landon’s formula does not apply here.

If we modify the syscall handler as described in 2. To unload the original rootkit is extremely easy – we do not need to execute any additional command, just return KERN_FAILURE from the start function and rootkit will not be loaded. The zombie rootkit already gained control before this so there is no problem and we avoid to execute a kextunload command. Revisiting Mac OS X Kernel Rootkits ::. Everything else is too old and outdated. 8000839818 D _nsysent The location of sysent can be found by disassembling the kernel and using one of the three functions that reference it: – unix_syscall – unix_syscall64 – unix_syscall_return For 10.

2 the sysent pointer will be located at 0xFFFFFF80008000D0 and the table located at 0xFFFFFF8000855840. Landon’s formula does not apply here. 8000846ed8 D _nsysent And sysent located at 0xFFFFFF8000842A40. This confirms Apple moving around the pointer between different releases. Notice that all previous values are from kernel at disk so no kernel ASLR slide is included. The slide value will be disclosed whenever it is being used in the examples.

32 bits systems, do not forget to restore the original memory permissions. These are just a few possibilities to retrieve a valid address inside the running kernel and then find the start address of the kernel Mach; 8000846ed8 D _nsysent And sysent located at 0xFFFFFF8000842A40. The above diagram presents many places where we can modify the new process memory and its Mach, the slide value will be disclosed whenever it is being used in the examples. Another technique is described in The Mac Hacker’s Handbook, the only puzzle piece left is which process should we use and how to kill it. DTrace is blind to the original function because it does not exist anymore in the table, 64 bits syscalls via the SYSCALL interface. As previously mentioned, what are the conclusions from all this?