Hi. Yesterday afternoon I experienced something very weird. A running
process would crash. ‘traceinfo’ gave me the crash address, so I
examined the map file to determine the function. I then disassembled
the object file and attempted to find the instruction that caused the
problem. I’ve done this many times, and it has always worked…until
now. The address I was given didn’t correspond to an instruction in the
disassembled file; instead, it pointed at the last byte of a move
To illustrate, here is a snippet of the disassembled code:
02b9 8b 45 f4 mov eax,-0cH[ebp]
02bc c7 40 08 00 00 00
00 mov dword ptr
02c3 8b 45 f4 L8 mov eax,-0cH[ebp]
02c6 ff 40 08 inc dword ptr +8H[eax]
The address I was given corresponded to 02c2, and I had another person
verify this (just in case it was a math error). My question is, huh?
Under what conditions could this occur? Any insight at all, or any
method of attack, would be appreciated.
I’m pretty certain that this is a memory/stack corruption of some sort.
Unfortunately, there have been several alterations and recompiles since
then, and the problem has disappeared again; I can’t make any new tests,
at least not until the problem reappears.