Sunday, November 11, 2007

How to crack a software

How to crack a software
tools required

you may download these tools from
i am not a master in this field but what i know i can share it with you.

now we have to crack soft. we have to make a backup of the exe file of this software.

as we are using dissembler it will dissemble the soft into its assembly codes so u need to know some basic codes which we need in this job

this part is copied from anither community post as i dont feel to rewrite the same thing again

EB-----------------jmp---------------------------Unconditional jump
90-----------------nop---------------------------No operation
75/0F85------------jne---------------------------jump if not equal
74/0F84------------je----------------------------jump if equal
77/0F87------------ja----------------------------jump if above
0F86---------------jna---------------------------jump if not above
0F83---------------jae------------------------jump if above or eq


now start

1st step-

try to register the software with some random character. you will get an error messege like "wrong code"
note down this code

dessemble the exe file using win32dasm

u will getthe codes in too many lines .. may be 10000 depending upon the size of soft.

now find "wrong code" by search option in the dissembler

as you can see the codes are written in modules

just the line you find the "wrong code" ..try to check for the start of that module

hint* check for the lines "unconditional and conditional jump statements"

see the memory addresses written there
eg- oo1a009877...

leave this thing here only

now open the same .exe file with the help of hiew
open hiew.exe and start working on it with keyboard only

select the folder and select the file to open it
after opening it u can see garbage characters that you can not understand.
press f4 and select 3rd option ie- decode

now you can see the codes

now note the addresses written on dissembler part where we left
on hiew window press f5 and press "." then foloowed by the address u noted there

now after coming to the desired position select edit option by pressing f3

now we have to revert the statements
like lets say we encountered jne
like jne to je and vice-versa by changing there corresponding values ie 84<-->85

like this revert all the loop statements noted on dissembler module where we left after searching

now after editing the values press enter key and then press "f9" to update the changes in the exe file

now exit hiew


now replace the .exe file with the one you just cracked

now it will accpet all the wrong codes which u will ener for registration and on entering the correct key only it will show error messege