Cheat Engine

AhMunRa · Posted: Fri Aug 06, 2010 11:34 pm Post subject: Tutorial 5 in CE is broken

In tutorial 5 when I find my address and I follow the steps to throw a NOP into that instruction, I click Stop, then Close, as soon as it closes I get an Access Violation error. Any tips? Is there a step I am missing? Following the instructions it looks like when you hit replace it is just putting in a comment not really modifying the instruction.

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

What was the code that You have found? Which OP system do You use?

AhMunRa · Posted: Sat Aug 07, 2010 4:32 pm Post subject:

Wasn't sure about spoiler for posting code.

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

It is not a spoiler, You can find posts on how to do the tutorial. Smile

The code You have found is right, so that is not a problem. I have the same.

AhMunRa · Posted: Sun Aug 08, 2010 1:14 am Post subject:

I meant the memory offset this code is pointing to is changing. I do have a laptop with XP Pro SP2, I may try that. I have only tried nopping out the code, haven't tried anything else yet.

I got your download in the morning I'll give it another shot. I'll also try to use another bit of code as opposed to nops. I'll also give straight patching the binary a shot see if that still crashes. If I nop that instruction in the binary and it still crashes it's gotta be something on my computer that is not liking the code running, if it works it has to be something in the way my OS, CPU, or memory are handling that code execution.

I've only been using CE for maybe 2 days now, but I can tell you even though the name is Cheat Engine this powerful little program is going into my reverse engineering toolbox.

I did use the debugger. Though does CE have it's own debugger or does it use a default one if the OS has one? I have Visual Developer Studio 2010 installed with it's debugger and a few other debugging tools I use. Ollydbg, IDA and a few others.

Thank you for the time you have spent to assist Geri, it's much appreciated.

***EDIT***
6:19 AM

Wow Geri, I looked at the file you posted, I wouldn't have thought of that.

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

It has a debugger in it. Pretty cool program indeed. Debugger, code injection and lots of other stuff.

AhMunRa · Posted: Sun Aug 08, 2010 3:52 pm Post subject:

I've looked at your code, and I'm still not sure why simply nopping the instruction is causing a crash.

Is it due to me trying to write protected memory?

Sorry to be a pain, but simply doing it is something completely different, if I don't understand it I can not put it to use.

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

I can nop codes and do code injection with CE in read-only memory without any problems. Especially in the tutorial, I don't know why are You having this problem.

Did You try to download CE again, install it and check it out? I had an issue once and everything seemed to be fine, except I had access violation in a CE function. I have downloaded it again and it was working. Don't know what went wrong then, download error or something, it solved the issue, that's what matters.

I hacked a few hundred games with CE already, did not have such issue. As I said, I am using XP Pro SP3 (32-bit) at the moment.
And of course I am the administrator on my comp.

Btw. I have tried to mess up the settings to cause an error, but it has worked fine for me in all cases.

HINT:
I was able to get access violation error in the Tutorial in some cases.
Check settings->Code finder and it should be on "Use debug registers". If You use "Memory access exceptions", You might get access violation.

AhMunRa · Posted: Sun Aug 08, 2010 4:24 pm Post subject:

Server 2008 is 64 bit only, but my XP is 32 bit and it does it there. I'll uninstall it and redownload I agree if it's doing it on both machines it must be a corrupt download.

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

HINT:
I was able to get access violation error in the Tutorial in some cases.
Check settings->Code finder and it should be on "Use debug registers". If You use "Memory access exceptions", You might get access violation.

You may also get an access violation if You use the kernel mode debugger options to find a code and You try to find a code again without closing the previous search.

But, if You use the default settings, these options are turned off, so You should not have this issue with the default options.

AhMunRa · Posted: Sun Aug 08, 2010 4:34 pm Post subject:

OMG Geri you are a god!. It was set to "Memory access exceptions". Thank you very much for your help. If I could +Rep you I would.

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

Doesn't matter, I suggest to not use that option unless You know why it is way much better. All I could achieve with that option was freezing games and crashes, I guess it requires huge amount of comp resources. It did not work for me ever.