1

I am trying to learn to get around Ollydbg, using Lena's tutorial. The latter is based on v.1.10 but I'm using 2.01. So far that went ok.

However, I now find myself in a situation where my result differs a lot from the tutorial (no 4).

I'm trying to catch the call for a messagebox in the code. The tutorial describes I should, with the messagebox open, pause Ollydbg, then return to the application and close the messagebox. This would make Ollydbg break after I clicked the box away and I would land right after the messagebox call in the code.

In my case though, as soon as I click pause, Olly leaves the main application module, landing on RETN in a subroutine of USER32.GetMessageA

Now I can't get back to the application at all, it's blocked. I have to continue the debugger in order to be able to get back to it again but this way I get no info about the messagebox.

Any tips how to proceed in order to get the expected result? I guess in this specific example I could just search for all messagebox calls in the code but that's hardly a good way, especially with large apps.

A related question, is there a possibility to "look back" on what happened, as in which code was called up to a certain moment?

Apologies if any of this doesn't make much sense.

  • Have you tried searching for all intermodular calls and breaking on all calls to message box? – Viktor Nov 6 '15 at 18:43
  • Hi namesake :) yes, I did that, that works, too, of course. But I wanted to know how I could use that in situations when I don't know the name of the window (or other function) called. – vic Nov 6 '15 at 19:17
4

alt + k to view or look back

here is a f9-> f12 -> alk + k output on a simple message box

Call stack of main thread
Stack     Data      Procedure                                     Called from                  Frame
0013FA78  7E419418   ???                                          USER32.WaitMessage+0A
0013FAB0  7E4249C4  /USER32.DialogBox2                            USER32.InternalDialogBox+0B1
0013FAB4  00A20142  |  Arg1 = 0A20142
0013FAB8  00000000  |  Arg2 = 0
0013FABC  00000001  |  Arg3 = 1
0013FAC0  00000000  \  Arg4 = 0
0013FAD8  7E43A956  /USER32.InternalDialogBox                     USER32.SoftModalMessageBox+6>
0013FADC  7E410000  |  Arg1 = USER32.<STRUCT IMAGE_DOS_HEADER>
0013FAE0  00152F38  |  Arg2 = 152F38
0013FAE4  00000000  |  Arg3 = 0
0013FAE8  7E43A016  |  Arg4 = USER32.MB_DlgProc
0013FAEC  0013FEF0  |  Arg5 = 13FEF0
0013FAF0  00000000  \  Arg6 = 0
0013FD98  7E43A2BC  /USER32.SoftModalMessageBox                   USER32.MessageBoxWorker+170
0013FD9C  0013FEF0  \  Arg1 = 13FEF0
0013FEE8  7E4663FD  /USER32.MessageBoxWorker                      USER32.MessageBoxTimeoutW+75
0013FEEC  0013FEF0  \  Arg1 = 13FEF0
0013FF40  7E4664A2  /USER32.MessageBoxTimeoutW                    USER32.MessageBoxTimeoutA+97
0013FF44  00000000  |  Arg1 = 0
0013FF48  001529C8  |  Arg2 = UNICODE "Multi-line text for a simp>
0013FF4C  00152AB0  |  Arg3 = UNICODE "Caption For A Simple And P>
0013FF50  00000000  |  Arg4 = 0
0013FF54  00000000  |  Arg5 = 0
0013FF58  FFFFFFFF  \  Arg6 = -1
0013FF74  7E450877  /USER32.MessageBoxTimeoutA                    USER32.MessageBoxExA+16
0013FF78  00000000  |  Arg1 = 0
0013FF7C  00401008  |  Arg2 = ASCII "Multi-line text for a simple>
0013FF80  00401070  |  Arg3 = ASCII "Caption For A Simple And Pla>
0013FF84  00000000  |  Arg4 = 0
0013FF88  00000000  |  Arg5 = 0
0013FF8C  FFFFFFFF  \  Arg6 = -1
0013FF94  7E45082F  /USER32.MessageBoxExA                         USER32.MessageBoxA+40
0013FF98  00000000  |  hOwner = NULL
0013FF9C  00401008  |  Text = "Multi-line text for a simple and p>
0013FFA0  00401070  |  Caption = "Caption For A Simple And Plain >
0013FFA4  00000000  |  Type = MB_OK|MB_DEFBUTTON1|MB_APPLMODAL
0013FFA8  00000000  \  LanguageID = LANG_NEUTRAL
0013FFB0  004010AE  /USER32.MessageBoxA                           msgbox.004010A8
0013FFB4  00000000  |  hOwner = NULL
0013FFB8  00401008  |  Text = "Multi-line text for a simple and p>
0013FFBC  00401070  |  Caption = "Caption For A Simple And Plain >
0013FFC0  00000000  \  Type = MB_OK|MB_DEFBUTTON1|MB_APPLMODAL

no you cant close a paused MessageBox not in v 1.10 or not in v 2.01
it is simply not possible period
you must be misreading or misunderstanding the tutorial

you need to set a breakpoint some where on any of the return address and continue execution or you can select a return address in call stack and hit f4 to execute until return

enter image description here

  • I don't think I misread, maybe I misunderstood. I quote from the tut: "Use this simple trick: Pause Olly first, now press Alt-F9 (return to user), and notice that Olly promises he will return to user as soon as you let him. [...] (Video goes back to App, closes the messagebox) Olly kept his promise, breaks right after the messagebox." – vic Nov 6 '15 at 18:13
  • yep alt+f9 is return to user code that sets a breakpoint on a return in call stack no problems there after you hit alt+f9 you cna notice the breakpoint ollydbg set in the list alt+k -> select a call retun and f4 -> f9 -> close ollydbg will break on the break – blabb Nov 6 '15 at 18:16
  • No, that's what I described, that doesn't work for me. No breakpoint is set, and I cannot return to the application window. – vic Nov 6 '15 at 18:22
  • 1
    i just checked it sets an internal hardware breakpoint here and the status bar show till user code and closing the msg box it breaks on user code Hardware breakpoints, item 0 Slot = 4 Type = Internal <---------------- Address = 7E42770A Module = USER32 Status = Active Disassembly = JMP USER32.7E42764D Comment = Log data, item 0 Address = 004010AE Message = User code reached – blabb Nov 6 '15 at 18:36
  • I am really confused now. It works. Well, it works now, for some reason, most of the times. The other times I still get the behavior I described in my question. It seem that when I switch back rather quickly using Alt-Tab after Alt-F9, it doesn't work. But that's not always reproducible. I had a streak of 6 times when it blocked, and after that I just couldn't get it to block again. I wish I could understand what's happening here. – vic Nov 6 '15 at 19:13
0

Have you tried in 1.10? I have and have no issue. Make sure you leave the dialog opened, and instead of hitting Alt-F9 I found the option in the menu.

It's possible but unlikely that this feature is broken in Olly 2

  • Thanks Gdogg. As I mentioned, it does work, just not consistently. Otherwise v2 was treating me well so far. – vic Nov 10 '15 at 20:43

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