wolvctf2023 baby-re Writeup

wolvctf2023 baby-re Writeup

1. problem_name  Writeup

Description

Just a wee little baby re challenge.

 

 

__int64 __fastcall main(int a1, char **a2, char **a3)
{
  char s[8]; // [rsp+0h] [rbp-100h] BYREF
  __int64 v5; // [rsp+8h] [rbp-F8h]
  __int64 v6; // [rsp+10h] [rbp-F0h]
  __int64 v7; // [rsp+18h] [rbp-E8h]
  __int64 v8; // [rsp+20h] [rbp-E0h]
  __int64 v9; // [rsp+28h] [rbp-D8h]
  __int64 v10; // [rsp+30h] [rbp-D0h]
  __int64 v11; // [rsp+38h] [rbp-C8h]
  __int64 v12; // [rsp+40h] [rbp-C0h]
  __int64 v13; // [rsp+48h] [rbp-B8h]
  __int64 v14; // [rsp+50h] [rbp-B0h]
  __int64 v15; // [rsp+58h] [rbp-A8h]
  __int64 v16; // [rsp+60h] [rbp-A0h]
  __int64 v17; // [rsp+68h] [rbp-98h]
  __int64 v18; // [rsp+70h] [rbp-90h]
  __int64 v19; // [rsp+78h] [rbp-88h]
  __int64 v20; // [rsp+80h] [rbp-80h]
  __int64 v21; // [rsp+88h] [rbp-78h]
  __int64 v22; // [rsp+90h] [rbp-70h]
  __int64 v23; // [rsp+98h] [rbp-68h]
  __int64 v24; // [rsp+A0h] [rbp-60h]
  __int64 v25; // [rsp+A8h] [rbp-58h]
  __int64 v26; // [rsp+B0h] [rbp-50h]
  __int64 v27; // [rsp+B8h] [rbp-48h]
  __int64 v28; // [rsp+C0h] [rbp-40h]
  __int64 v29; // [rsp+C8h] [rbp-38h]
  __int64 v30; // [rsp+D0h] [rbp-30h]
  __int64 v31; // [rsp+D8h] [rbp-28h]
  __int64 v32; // [rsp+E0h] [rbp-20h]
  __int64 v33; // [rsp+E8h] [rbp-18h]
  __int64 v34; // [rsp+F0h] [rbp-10h]
  __int64 v35; // [rsp+F8h] [rbp-8h]

  *(_QWORD *)s = 0LL;
  v5 = 0LL;
  v6 = 0LL;
  v7 = 0LL;
  v8 = 0LL;
  v9 = 0LL;
  v10 = 0LL;
  v11 = 0LL;
  v12 = 0LL;
  v13 = 0LL;
  v14 = 0LL;
  v15 = 0LL;
  v16 = 0LL;
  v17 = 0LL;
  v18 = 0LL;
  v19 = 0LL;
  v20 = 0LL;
  v21 = 0LL;
  v22 = 0LL;
  v23 = 0LL;
  v24 = 0LL;
  v25 = 0LL;
  v26 = 0LL;
  v27 = 0LL;
  v28 = 0LL;
  v29 = 0LL;
  v30 = 0LL;
  v31 = 0LL;
  v32 = 0LL;
  v33 = 0LL;
  v34 = 0LL;
  v35 = 0LL;
  puts("Just a baby reverse engineering challenge");
  printf("Ohio State University is the? ");
  fgets(s, 256, stdin);
  if ( !strcmp(s, "worst\n") )
  {
    puts("Correct! But the flag is elsewhere");
  }
  else if ( !strcmp(s, "best\n") )
  {
    puts("wctf{Must_be_fr0m_OSU}");
  }
  else
  {
    puts("wctf{A_t0tally_fake_flag}");
  }
  return 0LL;
}

IDA로 봤을 때 위 코드가 나왔다. 간단한 문제였다.

 

 

wctf{Oh10_Stat3_1s_Smelly!}