| Simple Crackme |
password: BXXGYYYBGIBBB
1) to find the length of the password check the instruction: cmp rax,D
Since D = 13 in decimal the string is 13 chars long
Then check the below instructions:
cmp dl,byte ptr ds:[rcx+r8]
jne crack_me.3D0473
That conditional jump goes to the failure section so obviously we need to check the dl register and make sure it matches the char being pointed to at address rcx+r8. What is dl register? It is simply the lowest 8 bits on the rdx register so to find its value go to the register section on your debugger and look at the 2 hex values which correspond to an ASCII character. Do this for every iteration of the loop and do not trust the comments on the disassembly. Reiterating, compare the dl register value with the address at rcx+r8. You can modify the rdx register as well so that you dont have to restart the debugging process every time you find a new character. |
2026-05-28 18:48 |