iOS level 2 crackme issues

[chq-matteo]

Describe the bug
There are issues with the level 2 iOS crackme.

I have already opened an issue on the main repository commjoen/uncrackable_app#10

I am putting this out there just in case there is someone who is stuck with the challenge.

The spoiler free tldr is:

• don't analyze the 64 bit version, the challenge is not cross platform at the moment. Due to some quirkiness, analyzing the 64 bit version can mislead you
• you should not be able to solve this with dynamic analysis
• you should not be able to find the expected password even statically, but you can recover the logic and then check that you were correct with the sources

I say should because for unintended reasons the challenge could be impossible to solve, not because it is hard to solve it.

crackme or other challenge
iOS crackme level 2, is a simple crackme with anti debugging checks. One of these checks is not working correctly

To Reproduce
Steps to reproduce the behavior:

1. Install the app
2. Copy the intended solution from the https://github.com/commjoen/uncrackable_app or from the writeup
3. The solution should fail the validation

Expected behavior
The solution should be accepted

Screenshots
Unfortunately I don't have an iDevice to test on

Additional context
Ghidra 9.1
The app for different reason should not work neither on 32 bit devices nor on 64 bit devices.

[commjoen]

Hi @chq-matteo , thank you for filing a bug. Let me get back to you about this.