| View previous topic :: View next topic |
| Author |
Message |
Amaz1ng How do I cheat?
Reputation: 0
Joined: 27 Jul 2011 Posts: 8
|
Posted: Sun Jul 31, 2011 11:05 pm Post subject: OllyDBG question about addresses |
|
|
Hey I figured this would be a good place to ask this question since there's some knowledgeable people here. I'm using olly to debug a program and im reading the instruction :
MOVE EDI, EDI
Olly says EDI = Game.009B8F38
but when I search the Game module for that address, the addresses end at like 00700000. So is there something I'm missing or what?
|
|
| Back to top |
|
 |
Slugsnack Grandmaster Cheater Supreme
Reputation: 71
Joined: 24 Jan 2007 Posts: 1857
|
Posted: Mon Aug 01, 2011 2:23 am Post subject: |
|
|
| mov edi, edi does nothing. it usually describes the start of code which sets up the stack frame. it is effectively a NOP that is used to fill up that code to be 5 bytes to allow hotpatching
|
|
| Back to top |
|
 |
AhMunRa Grandmaster Cheater Supreme
Reputation: 27
Joined: 06 Aug 2010 Posts: 1117
|
Posted: Mon Aug 01, 2011 8:27 am Post subject: |
|
|
I think it's the way Olly disassembles things, I have run into this problem as well using it. What I usually do when I find what I am looking for is I'll copy about 8 bytes prior to and after my instructions. Then you can search for those bytes, likely you won't collide with something outside the code segment you are looking for, this is why I use so many bytes to search for it.
_________________
<Wiccaan> Bah that was supposed to say 'not saying its dead' lol. Fixing >.> |
|
| Back to top |
|
 |
Amaz1ng How do I cheat?
Reputation: 0
Joined: 27 Jul 2011 Posts: 8
|
Posted: Mon Aug 01, 2011 4:46 pm Post subject: |
|
|
Thx. Hey I've been having probs with olly. How do I search for something like Game.001111111 or any address without manually having to scroll to it?
And when you said search for bytes, this is what I did - I clicked follow in dump and copied the 1st 8 bytes and did a binary search of those....nothing came up in my debugger screen.
|
|
| Back to top |
|
 |
AhMunRa Grandmaster Cheater Supreme
Reputation: 27
Joined: 06 Aug 2010 Posts: 1117
|
Posted: Tue Aug 02, 2011 7:51 am Post subject: |
|
|
In the code window you have 3 columns
| Code: | 771A1D6C > B8 7F010000 MOV EAX,17F
771A1D71 33C9 XOR ECX,ECX
771A1D73 8D5424 04 LEA EDX,DWORD PTR SS:[ESP+4]
771A1D77 64:FF15 C0000000 CALL DWORD PTR FS:[C0]
771A1D7E 83C4 04 ADD ESP,4
|
By bytes the actual bytecode 2nd column is what I use to search for what function I am looking for outside Olly
Example B87F0100033C98D542404 searched would take me to
| Code: |
mov eax, 17F
xor ecx, ecx
lea edx, dword ptr ss:[esp+4]
|
Using this method I have yet to enter a section of code I wasn't looking for. If you do by chance just increase your search size.
In your Run tools bar it is the black arrow with 3 dots. Clicking that should open a window to type an address to jump straight to.
_________________
<Wiccaan> Bah that was supposed to say 'not saying its dead' lol. Fixing >.> |
|
| Back to top |
|
 |
|