Marquires Crackme_v3_marquire Solution

I will say a little tricky but relatively easy.

Solution

First of all lets see how this crackme works

First we run the crackme and get this window

If we put wrong key it will return this message

lets open it in IDA and see how it works

Here is is IDA tree view

In above IDA tree image we can see that each key character is compared to a specific character in stack location and if all the keys match perfectly you will get this screen

Working Diagram

below is a work diagram of the procedure

Explanation

you can see input key “STILL_EASY?” in buffer at right

and in-built ASCII character string and stack location of each character at left

and in the middle is IDA disassembly code tree where every character from input buffer is being compared with corresponding character in stack

If all match then “right !” message will be shown otherwise “wrong !” will be displayed