simple-rev

[src = hackme] simple-rev

题目描述

A little bit harder

WP

直接IDA–>F5，得到：

int __cdecl main(int argc, const char **argv, const char **envp)
{
  char checking[64]; // [esp+Ch] [ebp-8Ch]
  char buffer[64]; // [esp+4Ch] [ebp-4Ch]
  int i; // [esp+8Ch] [ebp-Ch]

  printf("What is flag? ");
  fgets(buffer, 63, stdin);
  for ( i = 0; buffer[i]; ++i )
  {
    if ( buffer[i] == 10 )
    {
      buffer[i] = 0;
      checking[i] = 0;
    }
    else
    {
      checking[i] = buffer[i] + 1;  //简单的移位，只需要反向移位即可得到flag
    }
  }
  if ( !strcmp(checking, "UIJT.JT.ZPVS.GMBH") )
    printf("FLAG{%s}\n", buffer);
  else
    puts("Try hard.");
  return 0;
}

用python解决：

s = "UIJT.JT.ZPVS.GMBH"
r = ""
for i in s:
    r += chr(ord(i) - 1)
print(r)

输出flag。