Unhandled exception

Question

I am getting unhandled exception at some functionality due to enabling one of control and i am unable to find the exact reason.It gives me error at assembly instruction 00451901 add dword ptr [eax],eax but i can't figure out the basic reason of unhandled exception.Please suggest some software or any other thing to know the impact of enabling and disabling the control.

Answer 1

You get exception, because most certainly, eax contains value that is not an address to writable memory area.

So, the question is why this instruction was executed. Here's the hint:

Machine code for instructions add dword ptr[eax], eax is 01 00 .

That is, unexpected executing of this instructions usually means that you happen to execute some data (eg 32-bit constant '1').

This usually happens because of buffer or stack overflow in your code or calling function by pointer that wasn't properly assigned.

Check your array access and function pointers calls.