做crack me主要是为了学习一下通过逆算法和汇编语言

具体的破解步骤这里就不写了(nop大法)

主要写写通过汇编逆向出算法

 

0042FA57 >    83F8 04       cmp eax,0x4                              ;  判断输入name的长度是否大于4
0042FA5A  |.  7D 1D         jge short Acid_bur.0042FA79
0042FA5C  |.  6A 00         push 0x0
0042FA5E  |.  B9 74FB4200   mov ecx,Acid_bur.0042FB74                ;  Try Again!
0042FA63  |.  BA 80FB4200   mov edx,Acid_bur.0042FB80                ;  Sorry , The serial is incorect !
0042FA68  |.  A1 480A4300   mov eax,dword ptr ds:[0x430A48]
0042FA6D  |.  8B00          mov eax,dword ptr ds:[eax]
0042FA6F  |.  E8 FCA6FFFF   call Acid_bur.0042A170                   ;  输入长度小于4,跳转到0x0042a170,弹出错误对话框
0042FA74  |.  E9 BE000000   jmp Acid_bur.0042FB37                    ;  直接跳转到程序结尾
0042FA79  |>  8D55 F0       lea edx,[local.4]
0042FA7C  |.  8B83 DC010000 mov eax,dword ptr ds:[ebx+0x1DC]
0042FA82  |.  E8 D1AFFEFF   call Acid_bur.0041AA58
0042FA87  |.  8B45 F0       mov eax,[local.4]
0042FA8A  |.  0FB600        movzx eax,byte ptr ds:[eax]              ;  取出name第一个字符,赋值到eax寄存器
0042FA8D  |.  F72D 50174300 imul dword ptr ds:[0x431750]             ;  *0x431750 = *0x431750 x eax
0042FA93  |.  A3 50174300   mov dword ptr ds:[0x431750],eax          ;  )
0042FA98  |.  A1 50174300   mov eax,dword ptr ds:[0x431750]          ;  )
0042FA9D  |.  0105 50174300 add dword ptr ds:[0x431750],eax          ;  0x431750*2
0042FAA3  |.  8D45 FC       lea eax,[local.1]
0042FAA6  |.  BA ACFB4200   mov edx,Acid_bur.0042FBAC                ;  CW
0042FAAB  |.  E8 583CFDFF   call Acid_bur.00403708
0042FAB0  |.  8D45 F8       lea eax,[local.2]
0042FAB3  |.  BA B8FB4200   mov edx,Acid_bur.0042FBB8                ;  CRACKED
0042FAB8  |.  E8 4B3CFDFF   call Acid_bur.00403708
0042FABD  |.  FF75 FC       push [local.1]
0042FAC0  |.  68 C8FB4200   push Acid_bur.0042FBC8                   ;  -
0042FAC5  |.  8D55 E8       lea edx,[local.6]
0042FAC8  |.  A1 50174300   mov eax,dword ptr ds:[0x431750]
0042FACD  |.  E8 466CFDFF   call Acid_bur.00406718                   ;  生成serial中的数字
0042FAD2  |.  FF75 E8       push [local.6]                           ;  local.6是中间生成的password数字串
0042FAD5  |.  68 C8FB4200   push Acid_bur.0042FBC8                   ;  -
0042FADA  |.  FF75 F8       push [local.2]
0042FADD  |.  8D45 F4       lea eax,[local.3]
0042FAE0  |.  BA 05000000   mov edx,0x5
0042FAE5  |.  E8 C23EFDFF   call Acid_bur.004039AC                   ;  字符串拼接
0042FAEA  |.  8D55 F0       lea edx,[local.4]
0042FAED  |.  8B83 E0010000 mov eax,dword ptr ds:[ebx+0x1E0]
0042FAF3  |.  E8 60AFFEFF   call Acid_bur.0041AA58
0042FAF8  |.  8B55 F0       mov edx,[local.4]
0042FAFB  |.  8B45 F4       mov eax,[local.3]
0042FAFE  |.  E8 F93EFDFF   call Acid_bur.004039FC                   ;  关键call
0042FB03      75 1A         jnz short Acid_bur.0042FB1F
0042FB05  |.  6A 00         push 0x0
0042FB07  |.  B9 CCFB4200   mov ecx,Acid_bur.0042FBCC                ;  Congratz !!
0042FB0C  |.  BA D8FB4200   mov edx,Acid_bur.0042FBD8                ;  Good job dude =)
0042FB11  |.  A1 480A4300   mov eax,dword ptr ds:[0x430A48]
0042FB16  |.  8B00          mov eax,dword ptr ds:[eax]
0042FB18  |.  E8 53A6FFFF   call Acid_bur.0042A170
0042FB1D  |.  EB 18         jmp short Acid_bur.0042FB37
0042FB1F  |>  6A 00         push 0x0
0042FB21  |.  B9 74FB4200   mov ecx,Acid_bur.0042FB74                ;  Try Again!
0042FB26  |.  BA 80FB4200   mov edx,Acid_bur.0042FB80                ;  Sorry , The serial is incorect !

 

import binascii

input_name = "123456"
a = int(binascii.b2a_hex(input_name[0]),16) * int('0x29',16) * 2
print 'CW-' + str(a) + '-CRACKED'

 

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