Is it possible to reverse engineer an .exe file created with vb6 ?

[johnywalker]

Suppose we have a computer program compiled as exe file.
We also have the source code, but an accident happens and the source code is lost while the .exe survives.
Is is possible to bring back the source code from it ?
It happened to me several years ago and I couldn't so as the exe was gradually becoming unserviceable I wrote everything from the beginning, but is it in any way possible ?

[gibra]

Is is possible to bring back the source code from it ?

No.
You need to make a backup of your source code.

[The trick]

You can restore the algorithm and the approximate source code.
Just the example:
The original source code.
The restored algorithm from the executable.

[johnywalker]

You can restore the algorithm and the approximate source code.
Just the example:
The original source code.
The restored algorithm from the executable.

And does the restored code work straight off if you plug it into vb6 and give the same results ?

[baka]

I think its impossible to decompile an exe 100%, but you can get something out,
program like VB Decompiler Pro, gives u some info, but you need tons of work to make something out of it.
also, it would be terrible if a program like that existed, it would definitely be categorized as hacking.

[The trick]

And does the restored code work straight off if you plug it into vb6 and give the same results ?

Yes. You can compare. Just it was like a challenge. A guy asked for the code but he has only the executable. I asked the author don't post the code until i decompile (the author didn't mind) the executable in order to compare results. After i decompiled the executable the author posted the original one. All that I used was OllyDbg.

[DataMiser]

Just so you know decompiling to code and reverse engineering are two completely different things. Any program can be reverse engineered if you want to spend the time and effort required. Getting the source from an exe is a totally different thing. You can get the code to some extent from many types of exes but your best option is to make sure you have a backup or several of them.

[johnywalker]

Just so you know decompiling to code and reverse engineering are two completely different things. Any program can be reverse engineered if you want to spend the time and effort required. Getting the source from an exe is a totally different thing. You can get the code to some extent from many types of exes but your best option is to make sure you have a backup or several of them.

Yes I know.
This happened to me 10 years ago because of oversight and also there was no cloud storage those days.
I 'm more about hacking possibilities, or rather anti-hacking. If it is possible what can one do to make it impossible ?

[gilman]

You can restore the algorithm and the approximate source code.
Just the example:
The original source code.
The restored algorithm from the executable.

I do not understand Russian, but it sounds to me that those results could only be obtained if the program was compiled to pCode, in the case of compiling to native code, the results that I have managed to find, recovered the part of the design of the forms but the code seemed be in assembler

[qvb6]

In few cases, like if the IDE crashes and you have not saved the code, you could find part of the source in *.tmp files, but I guess you may not have those after this time. I think they are left in the same folder as the VBP file, but I am not sure.

[The trick]

I do not understand Russian, but it sounds to me that those results could only be obtained if the program was compiled to pCode, in the case of compiling to native code, the results that I have managed to find, recovered the part of the design of the forms but the code seemed be in assembler

The decompiled exe was compiled in the Native code not p-code.

[gilman]

What program are using?
With all that I found, the final code was awful