![]() Why is this happening and what am I doing anycodings_c++ wrong? if you need more info to be posted anycodings_c++ make sure to ask and I will provide it.Īfter enabling rtti I am still unable to anycodings_c++ perform a vmt hook, however I think i am anycodings_c++ getting closer and closer to it. My hook works if I use the dynamic address, anycodings_c++ but if I use the &vTable address then I anycodings_c++ get wrong results, index counter goes to anycodings_c++ random numbers and it never hooks anycodings_c++ anything!Ĭomparison between hk_class and anycodings_c++ hk_class1Īs you can see the most notable difference anycodings_c++ is that our virtual functions mismatch, in anycodings_c++ hk_class1 at the index 0 there is some RTTI anycodings_c++ complete object locator while there should anycodings_c++ be my virtual function add(int, int) If we take a look at the comparison we can anycodings_c++ see both yield different results Hk_class uses the dynamic address for anycodings_c++ testing purposesĪnd hk_class1 uses a anycodings_c++ calculated one Printing out (VOID*)ptr will give us the anycodings_c++ dynamic address of our object that is anycodings_c++ hook_this_classīack in my dll I have two seperate classes hk_class = reinterpret_cast(0x08C4138) to the class which points to a virtual method table (VMT or Vtable). Std::uintptr_t* ptr = reinterpret_cast((DWORD)vtable - (DWORD)GetModuleHandleA(nullptr)) In computer programming, the term hooking covers a range of techniques used to alter or. Now it seems that it does find the class anycodings_c++ correctly, however at the same time its not anycodings_c++ ( hear me out )įor testing purposes in my anycodings_c++ application where i'm trying to hook I added anycodings_c++ code that shows me the dynamic address of anycodings_c++ vtable std::uintptr_t* vtable = *reinterpret_cast(&object) ![]() Std::uintptr_t* vTable = reinterpret_cast(base + 0x4268) Īfterwards I cast the address to a class anycodings_c++ that is rebuilt from the class i'm trying to anycodings_c++ hook hk_class1 = reinterpret_cast(&vTable) To calculate the address of vmt I am doing anycodings_c++ base address of our process + virtual anycodings_c++ address of vmt auto base = reinterpret_cast((GetModuleHandleA(nullptr))) I made a simple application with 2 classes anycodings_c++ and virtual functions, My vmt hook doesn't override specific anycodings_c++ function pointers, what i'm trying to do is anycodings_c++ find the vmt > make a copy of it > anycodings_c++ switch the vmt pointers so my custom vmt anycodings_c++ gets called. VMT Hooking is really difficult to get your head around but after playing around with it for a while you will have an good understanding of how it works.Recently i've been learning about vmt anycodings_c++ hooking, however there is this one annoying anycodings_c++ bug that I cannot seem to fix and i'm not anycodings_c++ sure what exactly is the problem Magic! We VMT Hooked our virtual functions successfully! Now let's inject our dynamic link library. Inside our function_hooked_a and function_hooked_b we can see the o_function_a and o_function_b this is because we are calling the original function to avoid crashes occurring. Now let's run our program without the dynamic link library injected. And then we are getting the original functions assigning them into o_function_a and o_function_b. And then we are replacing the function vftable with function_hooked_a function and vftable with function_hooked_b function. Once we obtain the address we are assigning the variable vfunctable into the hook class. What we are doing there is we are getting the address of the Virtual Function Table by using ida pattern scanning "I'll have the project uploaded in github so you can get the pattern_scan function". #include #include class VirtualFunctions Īll the magic is happening is inside the MainThread. Here is an example of Virtual Functions being declared and used. Inside an class we can declare Virtual Functions and that allows us to override these virtual functions in our derived class. Now let's jump in and do the VMT Hooking! I know this sounds really complicated because it's really complicated because this skill allows us to manipulate/modify other software. The class has to be allocated in order for us to do the VMT Hooking. We achieve the VMT Hook by replacing an function inside the Virtual Function Table. VMT Hooking is really interesting because it's about hooking virtual functions inside an class.
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