攻防世界game

game

前言：不通过游戏的方法
1.打开附件
2.查壳
无壳
3.用ida分析
放入ida
4.shift+f12查看字符
往下拉
有个没有什么明显提示。
5.用f5
跟进main

（其实在这里就知道通关密码了）
拉到最下面发现是sub….所以这个里面可能是核心，跟进

再跟进

这个应该很重要
往下拉是一堆数字

这个应该那些数字的变化方式，分析发现函数进行了两次xor运算，xor的逆运算也是xor，那么我们就可以根据这个运算来写脚本得到最后的flag
这里看到v2和v59这就证明了这是两个数组的运算，所以我们应该将上面的字符串分成两个数组，分别从v2和v59开始
提取数据（shift+e）发现是
看规律可知是取第四个值即可，脚本如下

t=[  1,  198,  69, 188,  18, 198,  69, 189,  64, 198,  69,
  190,  98, 198,  69, 191,   5, 198,  69, 192,   2,
  198,  69, 193,   4, 198,  69, 194,   6, 198,  69,
  195,   3, 198,  69, 196,   6, 198,  69, 197,  48,
  198,  69, 198,  49, 198,  69, 199,  65, 198,  69,
  200,  32, 198,  69, 201,  12, 198,  69, 202,  48,
  198,  69, 203,  65, 198,  69, 204,  31, 198,  69,
  205,  78, 198,  69, 206,  62, 198,  69, 207,  32,
  198,  69, 208,  49, 198,  69, 209,  32, 198,  69,
  210,   1, 198,  69, 211,  57, 198,  69, 212,  96,
  198,  69, 213,   3, 198,  69, 214,  21, 198,  69,
  215,   9, 198,  69, 216,   4, 198,  69, 217,  62,
  198,  69, 218,   3, 198,  69, 219,   5, 198,  69,
  220,   4, 198,  69, 221,   1, 198,  69, 222,   2,
  198,  69, 223,   3, 198,  69, 224,  44, 198,  69,
  225,  65, 198,  69, 226,  78, 198,  69, 227,  32,
  198,  69, 228,  16, 198,  69, 229,  97, 198,  69,
  230,  54, 198,  69, 231,  16, 198,  69, 232,  44,
  198,  69, 233,  52, 198,  69, 234,  32, 198,  69,
  235,  64, 198,  69, 236,  89, 198,  69, 237,  45,
  198,  69, 238,  32, 198,  69, 239,  65, 198,  69,
  240,  15, 198,  69, 241,  34, 198,  69, 242,  18,
  198,  69, 243,  16, 198,  69, 244,   0]
for i in range(0,len(t),4):
    print(t[i], end='')
    print(',', end='')

这里面有一点，要注意，我在第一个加了一个1，就不多解释了。
下面那个同理，稍改一下就行。
下面是xor的脚本

b = [18,64,98,5,2,4,6,3,6,48,49,65,32,12,48,65,31,78,62,32,49,32,1,57,96,3,21,9,4,62,3,5,4,1,2,3,44,
     65,78,32,16,97,54,16,44,52,32,64,89,45,32,65,15,34,18,16,0,]
a = [123,32,18,98,119,108,65,41,124,80,125,38,124,111,74,49,83,108,94,108,84,6,96,83,44,121,104,110,32,95,117
    ,101,99,123,127,119,96,48,107,71,92,29,81,107,90,85,64,12,43,76,86,13,114,1,117,126,0,]
c = ""
for i in range(56):
    a[i] = a[i] ^ b[i]
    a[i] = a[i] ^ (0x13)
    c += chr(a[i])
print(c)

zsctf{T9is_tOpic_1s_v5ry_int7resting_b6t_others_are_n0t}