BinaryShield (Custom VM)

[ra1n]

View File

BinaryShield (Custom VM)

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This is my first attempt at a binary protector. Currently, the VM has very little protection, so this should be good for those interested in learning about VM-based obfuscation. I intend on uploading new challenges that feature my protector as I add more features.

BinaryShield source code: https://github.com/connorjaydunn/BinaryShield

GOAL:

- You must find the correct key. Simply patching to get a goodboy message is NOT allowed.
- Bonus points for devirt and explanation of your approach.
- MOST IMPORTANTLY, have fun!

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• Submitter
  ra1n
• Submitted
  09/24/2024
• Category
  CrackMe

 

Edited September 25 by ra1n

[Washi]

Fun and not too difficult challenge. I always like me some VM crackmes

Valid keys:

Spoiler

1859
2418
1638
299902
29763

Had enough fun reversing this so I made a full writeup with disassembler and devirtualized code:

https://blog.washi.dev/posts/binaryshield-vm-crackme/

Edited September 25 by Washi

[ra1n]

40 minutes ago, Washi said:

Fun and not too difficult challenge. I always like me some VM crackmes

Valid keys:

  Reveal hidden contents

1859
2418
1638
299902
29763

Had enough fun reversing this so I made a full writeup with disassembler and devirtualized code:

https://washi1337.github.io/ctf-writeups/writeups/misc/tuts4you/binaryshield/

Bravo! Thank you for the writeup. I apologize for the confusion with the multiple keys—it was only supposed to be one! I mistakenly checked if the input matched those constants instead of the current key calculation. Haha! I look forward to sharing my next upload, which will include anti-debugging features. Once again, amazing work!

EDIT: There appears to be a small typo in your lifted disassembly that would imply some of the keys are not correct.

Edited September 25 by ra1n