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CHM浏览器破解+算法分析

发表于: 2004-6-4 19:16 5914

CHM浏览器破解+算法分析

WXHing

2004-6-4 19:16

5914

呵呵，我又来了。                                                    又快到期末了，学习更忙了，但还是抑制不住对破解的兴趣，于是又带来三篇文章，请各位前辈指教！

第一篇

【破解作者】 WXHing
【作者邮箱】 [email]WXHing@163.com[/email]
【使用工具】 OllyDbg1.09,W32dasm8.93
【破解平台】 Win9x/NT/2000/XP
【软件名称】 CHM浏览器
【下载地址】中国共享软件注册中心
  [保护方式]    注册码保护
【软件简介】CHM浏览器是一个 CHM 工具，它能帮助你导出 CHM 中的文件。
CHM浏览器能够反编译出已编译的Windows HTML帮忙文件(*.chm)中的任何类型文件。它处理CHM文件就像ZIP文件一样。你可以像使用Winzip查看ZIP文件一样来运行或查看CHM中的文件。你可以通过双击文件的图标来查看HTML文件或图片文件。
【软件大小】 500Kb
【破解声明】本人菜鸟一只，初学破解，如有不当之处，还望各位前辈指教，先行谢过！
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【破解内容】首先用PEID检查无壳
         运行之，选择注册
         输入用户名 WXHing
         试练码 9876543210
         确定，出错！
         好，请出我的屠龙宝刀OD,装载目标程序，F9运行，注册它，弹出错误对话框，不要关它，回到OD界面，ALT+M，查看内             存镜像，搜索WXHing,下硬件访问断点dword，重新运行，重复第一步，确定。

0040FA02 .  8807             mov byte ptr ds:[edi], al                                     ；中断在这
0040FA04 .  8B45 08          mov eax, dword ptr ss:[ebp+8]
0040FA07 .  5E                pop esi
0040FA08 .  5F                pop edi
0040FA09 .  C9                leave
0040FA0A .  C3                retn
0040FA0B    90                nop
0040FA0C >  8A06             mov al, byte ptr ds:[esi]
0040FA0E .  8807             mov byte ptr ds:[edi], al

004227AD |.  E8 6DD5FFFF       call CHMUnpac.0041FD1F                                        ； ecx指向试练码
004227B2 |.  EB 13             jmp short CHMUnpac.004227C7
004227B4 |>  8BCE             mov ecx, esi
004227B6 |.  E8 D2ECFFFF       call CHMUnpac.0042148D
004227BB |.  85C0             test eax, eax
004227BD |.  74 08             je short CHMUnpac.004227C7
004227BF |.  57                push edi
004227C0 |.  8BC8             mov ecx, eax
004227C2 |.  E8 52FFFFFF       call CHMUnpac.00422719
004227C7 |>  8B07             mov eax, dword ptr ds:[edi]
004227C9 |.  5F                pop edi
004227CA |.  5E                pop esi
004227CB |.  8B40 F8          mov eax, dword ptr ds:[eax-8]                               ；eax=试练码位数‘9’
004227CE \.  C2 0800          retn 8
.........
........
00405A8F .  E8 CDCC0100       call CHMUnpac.00422761
00405A94 .  8B5424 0C       mov edx, dword ptr ss:[esp+C]
00405A98 .  68 30C94400       push CHMUnpac.0044C930                ; /Arg2 = 0044C930
00405A9D .  52                push edx                            ; |Arg1
00405A9E .  E8 83910000       call CHMUnpac.0040EC26                ; \CHMUnpac.0040EC26
00405AA3 .  83C4 08          add esp, 8
00405AA6 .  85C0             test eax, eax                                                 ；检测用户名是否为空
00405AA8 .  75 0C             jnz short CHMUnpac.00405AB6
00405AAA .  53                push ebx
00405AAB .  53                push ebx
00405AAC .  68 94A54400       push CHMUnpac.0044A594
00405AB1 .  E9 3B010000       jmp CHMUnpac.00405BF1
00405AB6 >  8B4424 08       mov eax, dword ptr ss:[esp+8]
00405ABA .  68 30C94400       push CHMUnpac.0044C930                ; /Arg2 = 0044C930
00405ABF .  50                push eax                            ; |Arg1
00405AC0 .  E8 61910000       call CHMUnpac.0040EC26                ; \CHMUnpac.0040EC26
00405AC5 .  83C4 08          add esp, 8
00405AC8 .  85C0             test eax, eax                                                 ；检测注册码是否为空
00405ACA .  75 0C             jnz short CHMUnpac.00405AD8
00405ACC .  53                push ebx
00405ACD .  53                push ebx
00405ACE .  68 84A54400       push CHMUnpac.0044A584
00405AD3 .  E9 19010000       jmp CHMUnpac.00405BF1
00405AD8 >  68 80A54400       push CHMUnpac.0044A580
00405ADD .  8D4C24 0C       lea ecx, dword ptr ss:[esp+C]
00405AE1 .  E8 FC6F0100       call CHMUnpac.0041CAE2
00405AE6 .  68 80A54400       push CHMUnpac.0044A580
00405AEB .  8D4C24 0C       lea ecx, dword ptr ss:[esp+C]
00405AEF .  E8 4F6F0100       call CHMUnpac.0041CA43
00405AF4 .  8B4424 08       mov eax, dword ptr ss:[esp+8]
00405AF8 .  8378 F8 10       cmp dword ptr ds:[eax-8], 10                            ；检测注册码长度是否等于0x10,十
00405AFC .  74 0C             je short CHMUnpac.00405B0A                                  进制16
00405AFE .  53                push ebx
00405AFF .  53                push ebx
00405B00 .  68 70A54400       push CHMUnpac.0044A570
00405B05 .  E9 E7000000       jmp CHMUnpac.00405BF1
00405B0A >  68 5CA54400       push CHMUnpac.0044A55C                ; /Arg2 = 0044A55C ASCII "eLRYdMs7IhHiObJg"          ；未知字符串入栈
00405B0F .  50                push eax                            ; |Arg1                                              ；试练码入栈
00405B10 .  E8 11910000       call CHMUnpac.0040EC26                ; \CHMUnpac.0040EC26
00405B15 .  83C4 08          add esp, 8
00405B18 .  85C0             test eax, eax
00405B1A .  0F84 CA000000    je CHMUnpac.00405BEA                                                                         ；相等则跳转，跳过去会显示这是被破解的注册码，迷惑人的
00405B20 .  8B4C24 08       mov ecx, dword ptr ss:[esp+8]
00405B24 .  68 48A54400       push CHMUnpac.0044A548                ; /Arg2 = 0044A548 ASCII "FkZQYRjGoBNcgJVU"
；未知字符串入栈
00405B29 .  51                push ecx                            ; |Arg1
；试练码入栈
00405B2A .  E8 F7900000       call CHMUnpac.0040EC26                ; \CHMUnpac.0040EC26
00405B2F .  83C4 08          add esp, 8
00405B32 .  85C0             test eax, eax
00405B34 .  0F84 B0000000    je CHMUnpac.00405BEA                                                                         ；相等则跳转，跳过去会显示这是被破解的注册码，迷惑人的
00405B3A .  8D5424 10       lea edx, dword ptr ss:[esp+10]
00405B3E .  57                push edi
00405B3F .  52                push edx                            ; /pHandle
00405B40 .  68 2CA54400       push CHMUnpac.0044A52C                ; |Subkey = "Software\YBSoft\CHMUnpacker"
00405B45 .  68 02000080       push 80000002                         ; |hKey = HKEY_LOCAL_MACHINE                            ；
00405B4A .  FF15 10B04300    call dword ptr ds:[<&ADVAPI32.RegCreat>; \RegCreateKeyA                                        ；看到了吗，过了这里，将把你的用户名和注册码写入注册表，接下去软件将会提示你下次启动时检验注册码是否正确，可以阴险的笑一下了，呵呵
00405B50 .  8B4424 0C       mov eax, dword ptr ss:[esp+C]
00405B54 .  8D4C24 0C       lea ecx, dword ptr ss:[esp+C]
00405B58 .  8B40 F8          mov eax, dword ptr ds:[eax-8]
00405B5B .  50                push eax
00405B5C .  6A 01             push 1
00405B5E .  E8 6DA10100       call CHMUnpac.0041FCD0
00405B63 .  8B4C24 18       mov ecx, dword ptr ss:[esp+18]       ; |
00405B67 .  8B3D 0CB04300    mov edi, dword ptr ds:[<&ADVAPI32.RegS>; |ADVAPI32.RegSetValueExA
00405B6D .  50                push eax                            ; |Buffer
00405B6E .  6A 01             push 1                               ; |ValueType = REG_SZ
00405B70 .  53                push ebx                            ; |Reserved
00405B71 .  68 80A24400       push CHMUnpac.0044A280                ; |ValueName = "Version"
00405B76 .  51                push ecx                            ; |hKey
00405B77 .  FFD7             call edi                            ; \RegSetValueExA
00405B79 .  8B5424 10       mov edx, dword ptr ss:[esp+10]
00405B7D .  8D4C24 10       lea ecx, dword ptr ss:[esp+10]
00405B81 .  8B42 F8          mov eax, dword ptr ds:[edx-8]
.....................
..................
好，重新运行，下断bp RegCreateKeyA ,不停按F9,太烦了，读了那么多注册表键值，一不留神就会跟丢的，好，清楚倚天剑吧，用W32dasm去分析，找到字符串“ V1.3 - 未注册21天试用版"，这是未注册版本的标志，看看它是从那里跳来的，004041CA(C), :004041F7(C), :00404229(C)
OK,重新载入，下断点，bpx 4041ca,F9运行，轻松着陆

004041CA . /75 6A             jnz short CHMUnpac.00404236
004041CC . |8D5424 14       lea edx, dword ptr ss:[esp+14]
004041D0 . |8D4424 3C       lea eax, dword ptr ss:[esp+3C]
004041D4 . |52                push edx                            ; /pBufSize
004041D5 . |8B5424 14       mov edx, dword ptr ss:[esp+14]       ; |
004041D9 . |8D4C24 2C       lea ecx, dword ptr ss:[esp+2C]       ; |
004041DD . |50                push eax                            ; |Buffer
004041DE . |51                push ecx                            ; |pValueType
004041DF . |6A 00             push 0                               ; |Reserved = NULL
004041E1 . |68 80A24400       push CHMUnpac.0044A280                ; |ValueName = "Version"
004041E6 . |52                push edx                            ; |hKey
004041E7 . |C74424 2C FF000000 mov dword ptr ss:[esp+2C], 0FF       ; |
004041EF . |FF15 04B04300    call dword ptr ds:[<&ADVAPI32.RegQuery>; \RegQueryValueExA
004041F5 . |85C0             test eax, eax
004041F7 . |75 3D             jnz short CHMUnpac.00404236
004041F9 . |8B4424 10       mov eax, dword ptr ss:[esp+10]
004041FD . |50                push eax                            ; /hKey
004041FE . |FF15 30B04300    call dword ptr ds:[<&ADVAPI32.RegClose>; \RegCloseKey
00404204 . |33DB             xor ebx, ebx
00404206 .  8D7C24 3C       lea edi, dword ptr ss:[esp+3C]                                  ；edi指向试练码
0040420A >  8A4F 01          mov cl, byte ptr ds:[edi+1]                                  ；获取后一字符
0040420D .  51                push ecx                                                       ；F7跟进
0040420E .  E8 1DFBFFFF       call CHMUnpac.00403D30
00404213 .  8A17             mov dl, byte ptr ds:[edi]                                  ；获取前一字符
00404215 .  52                push edx
00404216 .  0FBEE8          movsx ebp, al                                              ；刚转换后的字符存入ebp
00404219 .  E8 12FBFFFF       call CHMUnpac.00403D30
0040421E .  0FBEC0          movsx eax, al                                                 ；扩展存入eax
00404221 .  03E8             add ebp, eax                                                    ;ebp=ebp+eax
00404223 .  83C4 08          add esp, 8                                                       ;esp=esp+8
00404226 .  83FD 3D          cmp ebp, 3D                                                       ;ebp=3d吗
00404229 .  75 0B             jnz short CHMUnpac.00404236                         ；不等，就OVER了，改，让它等于0x3D                                                                                           注册码改为s7t6u5v4w3x2y1z0
0040422C .  83C7 02          add edi, 2
0040422F .  83FB 08          cmp ebx, 8
00404232 .^ 7C D6             jl short CHMUnpac.0040420A
00404234 .  EB 5C             jmp short CHMUnpac.00404292
00404236 >  8D4C24 10       lea ecx, dword ptr ss:[esp+10]
0040423A .  51                push ecx
0040423B .  8BCE             mov ecx, esi
0040423D .  E8 EE060000       call CHMUnpac.00404930
00404242 .  68 38A44400       push CHMUnpac.0044A438
00404247 .  8D5424 18       lea edx, dword ptr ss:[esp+18]
0040424B .  50                push eax
0040424C .  52                push edx
0040424D .  C68424 50010000 04 mov byte ptr ss:[esp+150], 4
00404255 .  E8 DBB80100       call CHMUnpac.0041FB35
0040425A .  8B00             mov eax, dword ptr ds:[eax]
0040425C .  8D8E AC000000    lea ecx, dword ptr ds:[esi+AC]
00404262 .  50                push eax
00404263 .  C68424 48010000 05 mov byte ptr ss:[esp+148], 5
0040426B .  E8 B9B70100       call CHMUnpac.0041FA29
00404270 .  8D4C24 14       lea ecx, dword ptr ss:[esp+14]
00404274 .  C68424 44010000 04 mov byte ptr ss:[esp+144], 4
0040427C .  E8 1FB60100       call CHMUnpac.0041F8A0
00404281 .  8D4C24 10       lea ecx, dword ptr ss:[esp+10]
00404285 .  C68424 44010000 01 mov byte ptr ss:[esp+144], 1
0040428D .  E8 0EB60100       call CHMUnpac.0041F8A0
00404292 >  8D4424 10       lea eax, dword ptr ss:[esp+10]
00404296 .  50                push eax                            ; /pHandle
00404297 .  68 88A24400       push CHMUnpac.0044A288                ; |Subkey = "SOFTWARE\YBSoft\CHMUnpacker"
0040429C .  68 02000080       push 80000002                         ; |hKey = HKEY_LOCAL_MACHINE
004042A1 .  FF15 08B04300    call dword ptr ds:[<&ADVAPI32.RegOpenK>; \RegOpenKeyA
004042A7 .  85C0             test eax, eax
004042A9 .  0F85 41010000    jnz CHMUnpac.004043F0
004042AF .  8D4C24 14       lea ecx, dword ptr ss:[esp+14]
004042B3 .  8D5424 3C       lea edx, dword ptr ss:[esp+3C]                                                       ;edx指向试练码
004042B7 .  51                push ecx                            ; /pBufSize
004042B8 .  8B4C24 14       mov ecx, dword ptr ss:[esp+14]       ; |
004042BC .  8D4424 2C       lea eax, dword ptr ss:[esp+2C]       ; |
004042C0 .  52                push edx                            ; |Buffer
004042C1 .  50                push eax                            ; |pValueType
004042C2 .  6A 00             push 0                               ; |Reserved = NULL
004042C4 .  68 80A24400       push CHMUnpac.0044A280                ; |ValueName = "Version"
004042C9 .  51                push ecx                            ; |hKey
004042CA .  C74424 2C FF000000 mov dword ptr ss:[esp+2C], 0FF       ; |
004042D2 .  FF15 04B04300    call dword ptr ds:[<&ADVAPI32.RegQuery>; \RegQueryValueExA
004042D8 .  85C0             test eax, eax
004042DA .  0F85 10010000    jnz CHMUnpac.004043F0
004042E0 .  8B5424 10       mov edx, dword ptr ss:[esp+10]
004042E4 .  52                push edx                            ; /hKey
004042E5 .  FF15 30B04300    call dword ptr ds:[<&ADVAPI32.RegClose>; \RegCloseKey
004042EB .  33ED             xor ebp, ebp
004042ED .  8D7C24 3D       lea edi, dword ptr ss:[esp+3D]                                     ；edi指向试练码
004042F1 >  8A47 FF          mov al, byte ptr ds:[edi-1]                                        ；eax取第一字符
004042F4 .  3C 61             cmp al, 61                                                          ；eax<61码
004042F6 .  7C 04             jl short CHMUnpac.004042FC                                        ；小于则跳
004042F8 .  2C 3D             sub al, 3D                                                          ；al=al-3d
004042FA .  EB 0A             jmp short CHMUnpac.00404306
004042FC >  3C 41             cmp al, 41                                                          ;al<41吗
004042FE .  7C 04             jl short CHMUnpac.00404304
00404300 .  2C 37             sub al, 37                                                          ；小于则跳
00404302 .  EB 02             jmp short CHMUnpac.00404306
00404304 >  2C 30             sub al, 30                                                          ；al=al-30
00404306 >  8AD8             mov bl, al                                                             ;bl=al
00404308 .  8A07             mov al, byte ptr ds:[edi]                                              ;al取下一位字符
0040430A .  50                push eax
0040430B .  E8 20FAFFFF       call CHMUnpac.00403D30                                     ；进入这个call进行字符变换
00404310 .  0FBEC8          movsx ecx, al                                              ；变换后的字符扩展存入ecx
00404313 .  0FBED3          movsx edx, bl                                                 ;bl扩展存入edx
00404316 .  03CA             add ecx, edx                                                    ；ecx=ecx+edx
00404318 .  83C4 04          add esp, 4
0040431B .  83F9 3D          cmp ecx, 3D                                                       ;ecx=3d吗
0040431E .  0F85 CC000000    jnz CHMUnpac.004043F0                                           ；不等则OVER
00404324 .  45                inc ebp
00404325 .  83C7 02          add edi, 2
00404328 .  83FD 08          cmp ebp, 8
0040432B .^ 7C C4             jl short CHMUnpac.004042F1
.........
.........以后是一些启动信息，与注册无关了

注意！很多地方都用到这个call,有必要研究一下

00403D30 /$  8A4424 04       mov al, byte ptr ss:[esp+4]                   ；eax=获取的字符16进制
00403D34 |.  3C 61             cmp al, 61                                        ; eax<61吗
00403D36 |.  7C 04             jl short CHMUnpac.00403D3C                      ;小于则跳
00403D38 |.  83E8 3D          sub eax, 3D                                        ；不小于，eax=eax-3d
00403D3B |.  C3                retn
00403D3C |>  3C 41             cmp al, 41                                        ;eax<41吗
00403D3E |.  7C 04             jl short CHMUnpac.00403D44                         ;小于则跳
00403D40 |.  83E8 37          sub eax, 37                                        ；不小于，eax=eax-37
00403D43 |.  C3                retn
00403D44 |>  83E8 30          sub eax, 30                                        ;小于，eax=eax-30
00403D47 \.  C3                ret
这个call是将字符转换
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【破解总结】

这个软件的注册码与用户名无关，只是满足关系式即可(注册码长度必须为16）
if eax>61
eax=eax-3D;
else eax>41
eax=eax-37;
else eax=eax-41;
前后两字符变换后的代数和等于0x3D,就OK了！

洋洋洒洒的一大篇，终于完成了，其实算法很简单。最后感谢您看完本文，谢谢！
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【版权声明】本文纯属技术交流, 转载请注明作者并保持文章的完整, 谢谢!