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[CodeEngn Basic 12] Can you replace? 본문

0x02 Reverse Engineer/0x01. CodeEngn

[CodeEngn Basic 12] Can you replace?

data type ConS_tanT 2017.08.20 09:47

문제 : 

You will see a success message after finding the key. 

 If you would want the Key itself to replace the success message in the MessageBox, 

 open up a Hex Editor and overwrite the key value in the offset range 0x???? ~ 0x????. 


 Q : find the key value and the offset range and write the solution in this format : key???????? 

 (first ???? for the start and the next 4 ?s for the end). 


바이너리 실행 : 

 

 [그림 1] 프로그램 실행 


00401063   .  BE 00304000   mov esi,12.00403000                      ;  ASCII "Oqiqb4EhM/4jISMjlzQf6kpGQwLrG+GEIY4bPc0JL/jWBfNLejmbme3garIrG4ngbXtWQY3Y2VdbvRxleHU9aGxFRLXkh5BDGVbm5gAAhGeBMBl65XKmZ9sbNn4xxi3cbD7M02MpwZ3BpN4lG3xyFPsofbhXbMu8Z/1rlqfdul/KLaGmkllOYRj9Mhnumqw1f464dK948rgz5JxpeSQHN45GlMNjb717x6IeCCMa6gN+Y"...


10진수로 바꾸는 함수 


0040107D   > \3D BF96287A   cmp eax,0x7A2896BF


10진수 : 2049480383 (정답)


하지만, 메시지박스에 이 숫자를 띄워라고 했다. 


그럼 주소를 조작하면 되는것 


 

 [그림 2] 조작된 주소 


 

 [그림 3] C0ngratulation `~` 


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