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zaas
发表于 2013-2-23 20:32
CM是什么？Crackme是什么？这是什么东西？楼主发的什么？
他们都是一些公开给别人尝试破解的小程序，制作 Crackme 的人可能是程序员，想测试一下自己的软件保护技术，也可能是一位 Cracker，想挑战一下其它 Cracker 的破解实力，也可能是一些正在学习破解的人，自己编一些小程序给自己破解，KeyGenMe是要求别人做出它的 keygen (序号产生器)， ReverseMe 要求别人把它的算法做出逆向分析， UnpackMe 是要求别人把它成功脱壳，本版块禁止回复非技术无关水贴。
【破文标题】一个KeygenMe的算法分析及算法注册机
【破文作者】zaas
【破解工具】OllyICE
【破解平台】WinXP
【破解声明】我是一只小菜鸟，偶得一点心得，愿与大家分享
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【破解内容】
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很久没有玩过什么软件了。今天闲暇，翻了翻Tuts4U，发现一个新的KeygenMe，玩玩。
首先查壳：peid显示是ASPack 2.12 -> Alexey Solodovnikov。
OD看了看，原来是修改了特征码假冒的。。。00401414 > $ 60 pushad
00401415 . E8 03000000 call 0040141D
0040141A E9 db E9
0040141B EB db EB
0040141C 04 db 04
0040141D /$ 5D pop ebp
0040141E |. 45 inc ebp
0040141F |. 55 push ebp
00401420 \. C3 retn
00401421 E8 db E8
00401422 01 db 01
00401423 00 db 00
00401424 00 db 00
00401425 . 00EB add bl, ch
0040135B . 68 95010000 push 0x195 ; /ControlID = 195 (405.)
00401360 . FF75 08 push dword ptr [ebp+0x8] ; |hWnd
00401363 . E8 16030000 call <jmp.&user32.GetDlgItem> ; \GetDlgItem得到注册名editbox的hWnd
00401368 . A3 90344000 mov dword ptr [0x403490], eax
0040136D . 16 push ss
0040136E . 81C3 8EA80800 add ebx, 0x8A88E
00401374 . 42 inc edx
00401375 . 83F2 3C xor edx, 0x3C
00401378 . 83E2 00 and edx, 0x0
0040137B . 17 pop ss
0040137C . 9C pushfd
0040137D . 58 pop eax ; 无用代码
0040137E . 25 00010000 and eax, 0x100
00401383 . 0BC0 or eax, eax
00401385 . F64424 01 01 test byte ptr [esp+0x1], 0x1 ; 判断是否成功获取注册名editbox的hWnd
0040138A . 0F85 D8010000 jnz 00401568
00401390 . E8 A4020000 call 00401639 ; 动态加载SendMessageA
00401395 . 68 9C344000 push 0040349C ; 注册名的保存地址Buffer
0040139A . 6A 15 push 0x15 ; len
0040139C . 6A 0D push 0xD ; WM_GETTEXT
0040139E . FF35 90344000 push dword ptr [0x403490] ; hWnd
004013A4 . FFD0 call eax ; SendMessageA
004013A6 . 8BD0 mov edx, eax ; eax返回获取字符串长度 len
004013A6 . 8BD0 mov edx, eax ; eax返回获取字符串长度 len
004013A8 . 42 inc edx ; len+1
004013A9 . C1E2 03 shl edx, 0x3 ; (len+1)<<3
004013AC . BE 80000000 mov esi, 0x80
004013B1 . 8D3C32 lea edi, dword ptr [edx+esi] ; 80+(len+1)<<3
004013B4 . 69D7 E6010000 imul edx, edi, 0x1E6 ; (80+(len+1)<<3)*1E6
004013BA . 83E6 00 and esi, 0x0
004013BD . 87F2 xchg edx, esi
004013BF . 33D2 xor edx, edx
004013C1 . 81FE 505D0100 cmp esi, 0x15D50 ; (80+(len+1)<<3)*1E6 >= 0x15D50
004013C7 . 73 05 jnb short 004013CE ; 不小于跳
004013C9 . E9 9A010000 jmp 00401568
004013CE > 83F8 0C cmp eax, 0xC ; 最多0xC位
004013D1 . 0F87 91010000 ja 00401568
解方程可知，用户名长度至少为6位，最大12位。004013F1 . B8 9C344000 mov eax, 0040349C
004013F6 . EB 06 jmp short 004013FE
004013F8 > 8030 4E xor byte ptr [eax], 0x4E ; ^=4E
004013FB . D020 shl byte ptr [eax], 1 ; (char ^4E)<<1
004013FD . 40 inc eax
004013FE > 8038 00 cmp byte ptr [eax], 0x0 ; 检测字符串是否为空
00401401 .^ 75 F5 jnz short 004013F8
for (int i = 0;i <len;i++)
{
*(str + i) ^= 0x4E;
*(str + i) <<= 1;
}
004011E7 /$ 55 push ebp
004011E8 |. 8BEC mov ebp, esp
004011EA |. 53 push ebx
004011EB |. 56 push esi
004011EC |. 33C0 xor eax, eax
004011EE |. 40 inc eax ; int eax =1
004011EF |. 33DB xor ebx, ebx ; int ebx =0
004011F1 |. 8B75 08 mov esi, dword ptr [ebp+0x8] ; str2
004011F4 |> 837D 0C 00 /cmp dword ptr [ebp+0xC], 0x0
004011F8 |. 74 3B |je short 00401235
004011FA |. 817D 0C B0150>|cmp dword ptr [ebp+0xC], 0x15B0
00401201 |. 77 05 |ja short 00401208
00401203 |. 8B55 0C |mov edx, dword ptr [ebp+0xC]
00401206 |. EB 05 |jmp short 0040120D
00401208 |> BA B0150000 |mov edx, 0x15B0
0040120D |> 2955 0C |sub dword ptr [ebp+0xC], edx
00401210 |> 85D2 |/test edx, edx
00401212 |. 74 0C ||je short 00401220
00401214 |. 4A ||dec edx
00401215 |. 33C9 ||xor ecx, ecx ; int i=0
00401217 |. 8A0E ||mov cl, byte ptr [esi] ; str[i]
00401219 |. 03C1 ||add eax, ecx ; eax += str[i]
0040121B |. 46 ||inc esi ; str++
0040121C |. 03D8 ||add ebx, eax ; ebx += eax
0040121E |.^ EB F0 |\jmp short 00401210
00401220 |> B9 F1FF0000 |mov ecx, 0xFFF1
00401225 |. 33D2 |xor edx, edx
00401227 |. F7F1 |div ecx
00401229 |. 52 |push edx ; eax %= FFF1
0040122A |. 8BC3 |mov eax, ebx
0040122C |. 33D2 |xor edx, edx
0040122E |. F7F1 |div ecx
00401230 |. 8BDA |mov ebx, edx ; ebx %= FFF1
00401232 |. 58 |pop eax
00401233 |.^ EB BF \jmp short 004011F4
00401235 |> C1E3 10 shl ebx, 0x10 ; eax =ebx <<10 +eax
00401238 |. 0BC3 or eax, ebx
0040123A |. 5E pop esi
0040123B |. 5B pop ebx
0040123C |. C9 leave
0040123D \. C2 0800 retn 0x8
然后进入字符串在此处理的过程。0040144F > \8D35 CC344000 lea esi, dword ptr [0x4034CC] ; 注册名Str
00401455 . EB 09 jmp short 00401460
00401457 > 8006 05 add byte ptr [esi], 0x5 ; str[i] += 5
0040145A . 8036 1D xor byte ptr [esi], 0x1D ; (str[i]+5) ^= 1D
0040145D . 83C6 01 add esi, 0x1
00401460 > 803E 00 cmp byte ptr [esi], 0x0
00401463 .^ 75 F2 jnz short 00401457
for (int k = 0 ; k< len ;k++)
{
*(str + k) += 5;
*(str + k) ^= 0x1D;
}
00401B60 /$ 8B5424 04 mov edx, dword ptr [esp+0x4]
00401B64 |. 8B4C24 08 mov ecx, dword ptr [esp+0x8]
00401B68 |. 8B4424 0C mov eax, dword ptr [esp+0xC]
00401B6C |. 03D1 add edx, ecx
00401B6E |. 83F0 FF xor eax, 0xFFFFFFFF ; char al = 0xFF
00401B71 |. 56 push esi
00401B72 |. F7D9 neg ecx
00401B74 |. 8BF2 mov esi, edx
00401B76 |. 74 14 je short 00401B8C
00401B78 |> 33D2 /xor edx, edx
00401B7A |. 8A140E |mov dl, byte ptr [esi+ecx] ; str3[i]
00401B7D |. 32D0 |xor dl, al ; str3[i] ^= al
00401B7F |. C1E8 08 |shr eax, 0x8
00401B82 |. 330495 803040>|xor eax, dword ptr [edx*4+0x403080] ; 一个大的Dword索引表 长度0x100
00401B89 |. 41 |inc ecx
00401B8A |.^ 75 EC \jnz short 00401B78
00401B8C |> 5E pop esi
00401B8D |. 83F0 FF xor eax, 0xFFFFFFFF
00401B90 \. C2 0C00 retn 0xC
0040148D . 68 96010000 push 0x196 ; /ControlID = 196 (406.)
00401492 . FF75 08 push dword ptr [ebp+0x8] ; |hWnd
00401495 . E8 E4010000 call <jmp.&user32.GetDlgItem> ; \GetDlgItem
0040149A . A3 94344000 mov dword ptr [0x403494], eax
0040149F . E8 95010000 call 00401639
004014A4 . 68 9C344000 push 0040349C
004014A9 . 6A 15 push 0x15
004014AB . 6A 0D push 0xD
004014AD . FF35 94344000 push dword ptr [0x403494]
004014B3 . FFD0 call eax
004014B5 . 68 9C344000 push 0040349C ; 同样的方法获取注册码editbox的内容
004014BA . E8 91FCFFFF call 00401150
004014BF . 83F8 09 cmp eax, 0x9
004014C2 . 74 05 je short 004014C9
004014C4 . E9 9F000000 jmp 00401568
004014C9 > 803D 9E344000>cmp byte ptr [0x40349E], 0x2D ; 第三位为"-"
004014D0 . 74 05 je short 004014D7
004014D2 . E9 91000000 jmp 00401568
004014D7 > 8D35 9F344000 lea esi, dword ptr [0x40349F]
004014DD . 8BFE mov edi, esi
004014DF . C605 9E344000>mov byte ptr [0x40349E], 0x0 ; 去掉"-"，把注册码搬运整合到一起
004014E6 . 57 push edi
004014E7 . 68 9C344000 push 0040349C
004014EC . E8 EF010000 call 004016E0
004014F1 . 68 CC344000 push 004034CC
004014F6 . 68 9C344000 push 0040349C
004014FB . E8 C5000000 call 004015C5 ; 十六进制字符串转数值
00401500 . 83E7 00 and edi, 0x0
00401503 . 8B3D CC344000 mov edi, dword ptr [0x4034CC]
00401509 . 5B pop ebx
0040150A . 0FCF bswap edi
0040150D . 03FA add edi, edx ; 注册码的数值+第一次处理得到的数值
0040150F . 3BFB cmp edi, ebx ; 是否和第二次处理得到的数值相等
00401511 . 74 02 je short 00401515 ; 相等注册成功，否则失败
很容易写出注册机。#include <STDIO.H>
#include <STRING.H>
#include <STDLIB.h>
int ProcessNameStepOne(const char * name,int len)
{
char *str = (char *)malloc(len + 1);
memset(str,0,len+1);
strncpy(str,name,len);
for (int i = 0;i <len;i++)
{
*(str + i) ^= 0x4E;
*(str + i) <<= 1;
}
unsigned int total_1 =1;
unsigned int total_2 =0;
for (int k = 0;k < len;k++)
{
total_1 += (unsigned char)(*(str + k));
total_2 += total_1;
}
total_1 %= 0xFFF1;
total_2 %= 0xFFF1;
free(str);
return (total_2<<0x10) + total_1;
}
int ProcessNameStepTwo(const char * name,int len)
{
const int index[256] = {
0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D};
char *str = (char *)malloc(len + 1);
memset(str,0,len+1);
strncpy(str,name,len);
for (int k = 0 ; k< len ;k++)
{
*(str + k) += 5;
*(str + k) ^= 0x1D;
}
unsigned int num = 0xFFFFFFFF;
for (int i = 0; i < len; i++)
{
*(str + i) ^= (num & 0xFF);
num >>= 8;
unsigned char x = *(str + i);
num ^= index[x];
}
num ^= 0xFFFFFFFF;
free(str);
return num;
}
int main(int argc, char* argv[])
{
char username[16]={0};
printf("UserName[Max len = 12]:");
scanf("%12s",username);
int len = 0;
while (*(username + len))
len ++;
if (len < 6 || len >12)
{
printf("Length of UserName is invalid.\n(must be 6 ~ 12) \n");
return 0;
}
unsigned int total = ProcessNameStepTwo(username, len) - ProcessNameStepOne(username,len);
total &= 0xFFFFFFFF;
printf("Serial number is %02X-%06X\n",total>>24,total&0x00FFFFFF);
return 0;
}
附件为KeygenMe。
【版权声明】破文是学习的手记，兴趣是成功的源泉；本破文纯属技术交流, 转载请注明作者并保持文章的完整, 谢谢!
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发表于 2013-2-23 20:44
