Reverse Engineering Basics (Crackme01 by AttilhaZ)

I got bored during rainy days, as a past time i'm doing some reverse engineering.

This will give you some idea on how i found the correct serial number of a crackme01 file. This file was created by Attilhaz for those who want to test their skills in reverse engineering.

To start with, let's fire up crackme01.exe

Try to put a wrong password and take note of that error message.

Now close crackme01 and fire up OllyDbg. Click File >>> Open >>> and browse open the crackme01.exe. The window will look like the one shown below.

Right click somewhere on the CPU main thread window, and go to "Search for" >>> and select "All referenced text strings"

Scroll down until you find the text string "The serial you have entered is invalid. Try again!!!".

If you will notice, it seems that there is a hard coded serial number on the program. The one that i'm referring to is the fourth text string "Rmth2hm89T21" before the "The serial you have entered is invalid. Try again!!!".

Let's take note of this serial. Close OllyDbg and fire up crackme01.exe. Try to input the serial number.