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0x01 实验环境：

操作系统	windows10
编译器	visual C++6.0
编译选项	默认编译选项
build版本	release版本	release和debug都可以

0x02 release

用vc++6.0编译出来一个release版本；

改变可执行文件得执行流程，使输入任何字符都可以进入正确的执行流程；

code

/*****************************************************************************
      To be the apostrophe which changed "Impossible" into "I'm possible"!

POC code of chapter 3.7 in book "Vulnerability Exploit and Analysis Technique"

file name   : crack_me.c
author      : failwest  
date        : 2006.9.20
description : used as a simple demo to show how to crack a PE file   
Noticed     : should be complied with VC6.0 and build into release version  
version     : 1.0
E-mail      : failwest@gmail.com

    Only for educational purposes    enjoy the fun from exploiting :)
******************************************************************************/

#include <stdio.h>
#define PASSWORD "1234567"
int verify_password (char *password)
{
    int authenticated;
    authenticated=strcmp(password,PASSWORD);
    return authenticated;
}

main()
{
    int valid_flag=0;
    char password[1024];
    while(1)
    {
        printf("please input password:       ");
        scanf("%s",password);
        valid_flag = verify_password(password);
        if(valid_flag)
        {
            printf("incorrect password!\n\n");
        }
        else
        {
            printf("Congratulation! You have passed the verification!\n");
            break;
        }
    }

    system("pause");
}