Tutorial Make and Crack A simple Crackme

[anath3ma]

well this tutorial its very stupid and easy :P i have spend 10 min of my life for this just post a comment lol:P anyway :P

 

first copy paste this code

 

#include <stdio.h>

#include <string.h>

int main(){

char log_name[25];

char log_pass[25];

printf("Enter The UserName:");

scanf("%s", log_name);

printf("Enter The PassWord:");

scanf("%s", log_pass);

if ((strcmp(log_name, "test1") == 0) && (strcmp(log_pass, "test") == 0)){

printf("Correct! U Can Enter Now \n");

}

else{

printf("\n Sorry Wrong Pass or UserName\n");

return 0;

}

}

 

pure C code with some functions from string.h(strcmp)

 

compile it using gcc(gcc -o crackme.exe crackme.c) or another compiler

 

ok after compile load it on ollydbg

 

u should see something like that

 

 

Oh wtf is this ???:P this is the asm code of the progam in this shits we do the changes the truth is maybe u need to change only 1 value ex xor eax,eax to nop and this can make the program work registered or add al, bl to move al, 1 anyway -beep- this lets move

omg i think the things are very clear here!!!

:) wel with this we can make a keygen but its not so simple on programs with more code...u need to search a lot anyway now if we wanna patch it and if we give null on username and pass to recive the same do the next

ps u can do it with many ways i will show you one now

change

JNZ  SHORT 00401334  to  JMP    SHORT 00401326 at adress(0040130D)

and

JNZ  SHORT 00401334  to  JMP    SHORT 00401326 at adress(00401324)

 

i hope to catch the point right ?:P

also the tools you need is

a C/C++ compiler

and the ollydbg

dont forget to comment :P

[DrenepiaWorld]

so here is my comment

??? ??? ??? ??? ??? ???

[NotAbastard]

Just google the programs he mentions and then follow the instructions, it ain't as hard as it may seem :D