crackmes/1

CrackMeOne

Steps

• Launch x32dbg and open the exe

• Run up until EntryPoint

• Open the strings view

• Find

  Congratulations, you found the secret password

  This must be our code path on success. Double click to find it in the assembly view.

• Insert some breakpoints before and play around with entering password (anything is fine) and stepping through code, observing registers etc.

• Observe that there is a loop iterating through bytes at *eax and *ecx and comparing them. eax points to our entered password, ecx points to j5%9lk.

• Clearly we are checking for equality between these two strings, thus this is the password.

• If we complete the loop, we jump straight to the test eax, eax that gates the success path. If we don't, we jump a few instrs before, where eax is set to a value that is always non-zero (thus we take the branch, which we don't want to). eax will be zero in the success path due to the final equality check being performed on the null-byte string terminator.## Solution

Solution

Password: j5%9lk.