I wanted to support this community with a new series about cracking self-made applications. In this series I'll give you some applications especially made for cracking the password, license mechanism, etc. in different languages like Python (Easy for RE), C# (An interesting language for RE; Keywords are decompiling and obfuscation), C/C++ (Here comes the using of debuggers and ASM into play), and maybe some other languages too.
To make this a bit more helpful for beginners I will always share my own way of accomplishing this at the end of my post. Finally I want to add that I hope to help you, although my language won't be that good .
Description of the todays RE Challenge
This challenge is the first one I publish here, so it is extremely easy. Ok, Python is not that great for password hiding, but this one is not even near to uncrackable.
The Programm wants as argument the password you want to try. Mmh, when I think about it there's nothing other to say about it . Just try to get the password, but don't bypass the login in the script! We'll come to challenges, where you have to change the program later .
You can get the Script here: http://pastebin.com/G89WdxfT (Tested for Python2 on Windows)
I hope you'll have fun with these little challenges and learn something new. Below you'll find my example solution .
My own Way for Accomplishing the Task
Because I don't know a way of using spoilers here (Note: This feature would be very helpful; Maybe some admin could add that?), I'll use a pastebin link here for the guide. I recommend to try the challenge on your own first, although when you don't know anything about RE. See solution here: http://pastebin.com/1uEprrtd