[crackme] Little challenge ...

[Gyver75]

I've downloaded this crackme long time ago. Its difficult could be 2/10 but it's really funny and, above all, instructive. If you want to try something different ...

Crackme.rar

[ByteReverser]

buddy i download this but its not exe  its  file?

[Gyver75]

yes ... the main purpose of this type of challlenge is examine the file and then, find its secret! A good start point is an Hex editor and, obviously, internet search! :-)

[mrexodia]

Solution:

PEEKPOKE

Tutorial:

• Open up 'Cr4ckM3' in your favorite hex editor
• First check if you can find the signature (first 4-8 bytes) on google: 3F 3F 3F 3F or 31 35 34 31 have no interesting results, let's look further down.
• If you scroll down to 0x2D0 you will find a commonly-occurring pattern: A5 29 4A 52 94 <- various intersting hits on google!
• First link: http://ist.uwaterloo.ca/~schepers/formats/G64.TXT tells us the file should start with 47 43 52 2D instead of 3F 3F 3F 3F. Change this and save the file with the extension .g64
• Download WinVICE (commodore 64 emulator): http://www.zimmers.net/anonftp/pub/cbm/crossplatform/emulators/VICE/WinVICE-2.3-x86.zip
• Open 'x64mm.exe' and use 'File->Autostart Disk image' and select our saved .g64
• Appears to be running:

  

• Download http://style64.org/dirmaster to browse the contents of the .g64 file
• Let's look inside "SECRET":

  

  

• Try "PEEKPOKE" as code and everything appears to be in order:

  

Mr. eXoDia

Edited November 30, 2014 by Mr. eXoDia

[Teddy Rogers]

The [crackme] tag has been added to your topic title.

Please remember to follow and adhere to the topic title format - thankyou!

[This is an automated reply]

[Gyver75]

Well done Mr. eXoDia!   Your solution is certainly faster than mine ... probably an old C*4 user would have had a different approach