14.6.13 brute-force acid_burn

Broland Delphi 3.0.

There are serial + name verification and serial verification.

The program uses MessageBox, so BP messageboxa. (showmessage is not allowed)

• Serial + name verification

  Enter:

  The standard error message is:

  The program stops at the messageboxa address,

  Jump from 0x0042a1a9 to this address.

  The error message should be pushed here.

  Go up and find the first sentence of this subroutine, that is, 0x42a170.

  Enter serial and name again.

  The program stops at 0x42a170.

  View the stack.

  Jump from 0x 0042fa74 to this address.

  There are different prompts near the address. congratz... Is the author wrong.

  Find the first sentence of this subroutine, at 0x0042f998.

  Enter serial and name again.

  After the program stops, it starts to use F8 for one step.

  Because it was originally intended to be cracked, you can skip non-comparison and jump points quickly.

  Until 0x0042fa57 CMP eax, 4

  The jump will not be executed here, but will go down directly. below is the error message we see.

  The jge value is greater than or equal to the jump. The signed. Modify the flag S. The jump is executed to avoid errors.

  Continue F8 until 0x42fb03.

  How can I miss the success prompt! Modify the flag Z. The redirection fails. Continue to f8.

  As a result, the attack was successful.

  Change jge to JMP, delete jnz NOP, save it, and kill this crackme (part ).

• Serial

  It's no different from the above...

  No fees.

From the perspective of brute-force cracking, this crack me is not very difficult...

The algorithm is not analyzed and cannot be reached.

The first independent cracking cm.