What to Inject
Part 8: The memory location we wish to overwrite, -2
This becomes the new second chunk’s forward pointer
The value we put there is the location of the free() function call-12
From our example 0x08049548 – 0xc
Part 9: The value to overwrite
This becomes the new second chunk’s backward pointer
This points to our shellcode
From our example this is 0x08049560
Part 10: NULL terminate the string (\x0)