First Crackme

[mattheig 10]

Language: C/C++
Platform: Windows x86
OS Version: Windows
Packer / Protector: None

Description:

Simple obfuscation. Change "input a number" text. 

Gold: add +1 to sum factorial

Screenshot:

 

OBFTest.exe

Edited April 13, 2019 by mattheig
wrong exe (see edit history)

[NOP 90]

Program cannot start because VMprotect dll is missing

Quote

Packer / Protector: None

Are you sure this is using no packer or protector?

[mattheig 10]

@NOP reupload

 

Edited April 13, 2019 by mattheig (see edit history)

[ForlaxPy 12]

[*] Changed the text

 

How I did it?
 

Spoiler

 

Simply by breaking the runtime in this address: 00CA675B then you would be able to see the text in the edx register, so I changed that text from memory dump as you can see here

 

 

 

[*] Added +1 to sum factorial

How I didt it?

Spoiler

Same story go to 00CA5070 and edit the eax reg

 

For now that the addresses are well know you can easily calculate the string value and change edit these reg values by patching the exe so it always return what ever you want.

Edited August 16, 2019 by ForlaxPy
More details (see edit history)