How to read an EXE?

wicked23 · 07-19-2007, 11:28 AM

Hello, I 've never posted in this section before. Anyways I have an old exe file I found on our server that was created before I got here. I would like to make some changes to fit our needs. This program opens an interface in ms-dos. I changed the exe to a .bat file and tried editting it. Except it is in some sort of code. Yes I am not a programmer, but have gotten my feet wet in vb6.0 and html.

So my question is?
1. How do I find out what the exe is written in, so i can edit it?

If you need more info please just ask.
Thanx.

Wolff · 07-19-2007, 12:28 PM

An exe file is always binary, meaning it´s already compiled. You need to disassemble - reverse engineer - it, and that will most likely just bring it back to C++ or into assembly code, which won´t help you if only know VB 6.

Also, you may be prevented, legally, from editing that exe file, and in addition, if it is part of an application, you may need to edit several files not just the EXE.

Essentially, what you´re asking can be done, but it seems like a pointless task and if you only know VB 6 you will be in for some long hours doing what you want.

Vormund · 07-19-2007, 12:39 PM

Quote:

Originally Posted by Wolff

Essentially, what you´re asking can be done, but it seems like a pointless task and if you only know VB 6 you will be in for some long hours doing what you want.

Indeed, it is not easy to reverse-engineer code, so doing something like this would take an extreme amount of time without prior knowledge. It would most likely be easier to rewrite the program a hundred times over...:eek:

wicked23 · 07-19-2007, 12:41 PM

Legally I'm covered, a former employee created it. It is owned by us.
Pointless no. Since I am getting paid for it it is not pointless.

Wolff · 07-19-2007, 12:44 PM

Quote:

Originally Posted by wicked23

Legally I'm covered, a former employee created it. It is owned by us.
Pointless no. Since I am getting paid for it it is not pointless.

My point is that reverse engineering is very hard. You said you know Visual Basic 6 and HTML. To do this would most likely AT LEAST require GOOD and solid knowledge of C++, but most likely you will have to dabble with assembly code. Are you familiar with any of these languages?

You can read here for some more info on decompiling: http://en.wikipedia.org/wiki/Decompiler

Binary exe files are not like HTML where you can just go in and edit the source code as text, exe files are binary files, it´s zeroes and ones.

Wolff · 07-19-2007, 12:45 PM

And like Vormund says, it will likely take LESS TIME to rewrite the code than decompile, edit and recompile/redeploy.

Vormund · 07-19-2007, 12:47 PM

Quote:

Originally Posted by Wolff

Binary exe files are not like HTML where you can just go in and edit the source code as text, exe files are binary files, it´s zeroes and ones.

I don't know why, but this line reminded me of "There are 10 types of people in this world...".

Wolff is right though in terms of it'll be difficult. But if they're willing to pay you for attempting this, go for it! Getting paid to learn something fun - you'd be crazy to turn that down...

wicked23 · 07-19-2007, 01:14 PM

Exactly. Though I may not know code like you guy's I have always been interested in it. I got interested in it during an Oracle class. Our assignment with coming up with the correct string to pull info seemed facinating. While I know it is not exactly the same I also have made access based programs containing multiple forms and tables and functions which gives me a feel on how things work. So yes if I can learn more of this on the company dime why not right.

So basically your sayin I have a binary based file that could have been written in any language. i need to decompile it in order to get to the root source code. So i can see it in english and change it.

So is there a freeware or non free decompilier that can scan an exe and tell what it was written in so I can buy the program or does this not work this way.

wicked23 · 07-19-2007, 02:19 PM

Thanks for everyone's advice. But someone here finally remembered it was written using QB45. I found it hidden in a folder on our server. Problem solved.

Wolff · 07-19-2007, 04:03 PM

Quote:

Originally Posted by wicked23

Thanks for everyone's advice. But someone here finally remembered it was written using QB45. I found it hidden in a folder on our server. Problem solved.

I´m puzzled as to how this solves anything. Unless you have access to the source code? Chances are you will not decompile the code back to QB45 and you´re still stuck with at least one binary (there are probably libraries as well?) file.

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