badryuner's BadPin

Author:
badryuner

Language:
.NET

Upload:
2023-06-16 13:55

Download

Platform:
Windows

Difficulty:
5.2

Quality:
4.4

Arch:
x86-64

Downloads:
21

Size:
591.25 KB

Writeups:
1

Comments:
4

Description

.Net 6.0 Crackme. Used own virtualizer. It's made of poop and sticks, but it gets the job done. No any anti-debug thing is used there. Sometimes it can crash (read above) if you use the mouse instead of the arrows. Goal: find the pin code. And preferably write the solution) You can patch the code or debug or keygen it, if that helps you, just find the hidden pin code.

Comments (4)
Writeups (1)

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devsoft on 2023-06-19 17:05: This is madness... Has someone any info that can help on this?

badryuner on 2023-06-20 10:07: 1) All instructions are almost identical. Most of the difference is one opcode, which they just emulate. So just rename most methods according to it. Yeah, about 20 opcodes are int-long conversion, float-long etc, ignore them, in new versions I reduced it. 2) You probably have the right part of translated methods, it's time to put the right breakpoint in dnspy and trace the logic. Hint where to put the bryakpointe (flip the screen, don't want to spoiler): ˙poɥʇǝɯ ǝuo ʎןuo sı ǝɹǝɥʇ ǝɹǝɥʍ ǝʇɐƃǝןǝp ɐ uı. IGNORE MAIN and START, it just initializes TerminalGUI there. It's scary. Don't try to trace it. 3) Check a number with a number a couple of times (so you can't get a pin easily, heh), just find which numbers and pick up a pin.

badryuner on 2023-06-20 10:07: If you have any questions, you can write me on Discord)) In Discord I have the same nickname.

devsoft on 2023-06-20 10:43: Hum, I have done that so far for the calli Instructions. They lead to .NET managed code, and only after hours of trying to reverse the IL code of the virtualized functions I've realized that the code is unmanaged ^^. So I see him operating those 2 number's, I see the consequent toInt64 but even with manual combination no luck for me. Anyway, I'll follow your tip's and check out if I can take anything out of this. This approach is very good, Gratz on such a great job!

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Solution by devsoft on 2023-07-24 14:34:
PDF File with .NET code reversion and solution, provided with the help of the author.

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badryuner's BadPin