CrackMe Challenge [Part 1] - Introduction / Very Easy Password Mechanism (Python)


(The C# Dude) #1

Hey Mates,
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 :smile:. 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)

Conlusion

I hope you’ll have fun with these little challenges and learn something new. Below you’ll find my example solution :slight_smile:.

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

|-TheDoctor-|


1337 of the w33k #4 (5/23-28/2016)
(appie) #2

i m trying to run it but i still get this ‘The program is still running! Do you want to kill it’ .
i don’t know nothing about encryption just what it is.
but just because you say its easy i where trying it but no succes :frowning:


(The C# Dude) #3

You copied the program to a file called simplePassword.py, tried to run it with python2 and got that error? I assume you use Windows? Python2 is installed? Many questions here :grin:. And “Yes” it is very easy :wink:


(toxicwapor) #4

Getting the same error as @appie35
Windows 10 64-bit
Python 2.7


(The C# Dude) #5

This occurs when you run the program via terminal?


(toxicwapor) #6

No, I saved the file in simplePassword.py and then opened the Editor mode and ran it in the shell.


(The C# Dude) #7

Interesting thing… Tried it again and it works well :neutral_face:. Someone knows what’s going on? Maybe problems with Win10? I use Win7…


(The C# Dude) #8

Is Python2 crashing or what?


(toxicwapor) #9

Which version of Python2 do you use?


(The C# Dude) #10

2.7.10, but that shouldn’t make a difference…


(toxicwapor) #11

Can you post a screenshot of the IDLE and the Shell’s output window?


(The C# Dude) #12

Works like it should^^


(The C# Dude) #13

Do you have a Linux Live Distro? Try with it; would be interesting to know if it works then :wink:


(toxicwapor) #14

Aah! I figured, you run the file through Command Prompt but i use the Python Shell in the IDLE. The problem occurs that after the execution of the code, it automatically terminates and since it is still running, it prompts the message.
You should have specified that you used CMD.


(The C# Dude) #15

Ok, I always run via cmd and thought it’s normal^^. Nice that it works now, good luck with cracking!


(toxicwapor) #16

Works like a charm now. For others: Just drag the file into the CMD window and press enter.


(toxicwapor) #17

Done. You know @TheDoctor! :wink:


(The C# Dude) #18

Wasn’t that hard, hugh? Would be good if you don’t post the password in the comments, maybe someone accidently reads it :wink:


(The C# Dude) #19

In the next part I’ll cover C# reversing and that’s a much more interesting topic, but I wanted to start with something very easy, so Python was my favourite as begin^^.


(toxicwapor) #20

Wouldn’t be able to help myself with C# though.