Blowfish初探-英语会话精灵 3.2
首先严重的感谢看雪论坛的作者们,特别感谢加密与解密第二版,是它一步步引领我前进。
本文的加密解析章节比较乱,基本是跟着思路写下来的,比较原始的体现了我破解的思路。
Blowfish是根据OD载入的文字提示及看雪精华5-upfeed1的大作-BlowFish尝试-代码确定的。
1.脱壳:
PEBundle 0.2 - 3.x -> Jeremy Collake
00638000 t> 9C pushfd
00638001 60 pushad
00638002 E8 02000000 call topbar.00638009
...
0063836F 61 popad
00638370 9D popfd
00638371 68 01306300 push topbar.00633001 ; 参考RORDBG来到这里
00638376 C3 retn
dump+peid:ASPack 2.12 -> Alexey Solodovnikov
00633001 60 pushad
00633002 E8 03000000 call topbar.0063300A
00633007 - E9 EB045D45 jmp 45C034F7
...
006333AF 61 popad ; 直接go到这里
006333B0 75 08 jnz short topbar.006333BA
006333B2 B8 01000000 mov eax,1
006333B7 C2 0C00 retn 0C
006333BA 68 70D35600 push topbar.0056D370
006333BF C3 retn
dump+peid:Borland Delphi 6.0 - 7.0
不用修复,运行ok。
2.断点:
机器码:0604C-5FBB0
练码:9876543210123456
确认后提示:注册码无效!
OD载入脱壳后程序,串参考:
地址=004CF2F7 反汇编=mov edx,up-2.004CF530 文本字符串=注册成功!请保留好您的注册码,谢谢!
地址=004CF3EF 反汇编=mov edx,up-2.004CF5AC 文本字符串=注册码无效!
往上找入口:
004CF160 /. 55 push ebp
004CF161 |. 8BEC mov ebp,esp
3.流程:
:004CF1A4 8B8520FFFFFF mov eax, dword ptr [ebp+FFFFFF20]
:004CF1AA E85157F3FF call 00404900
:004CF1AF 83F80F cmp eax, 0000000F ; 注册码长度要大于F
:004CF1B2 0F8EEB010000 jle 004CF3A3
* Possible StringData Ref from Code Obj ->"reg.dll"
:004CF1B8 68BCF44C00 push 004CF4BC
* Reference To: KERNEL32.LoadLibraryA, Ord:01E6h
:004CF1BD E8FA7CF3FF Call 00406EBC
:004CF1C2 8BF0 mov esi, eax
:004CF1C4 85F6 test esi, esi
:004CF1C6 0F8407010000 je 004CF2D3
:004CF1CC 8D8526FFFFFF lea eax, dword ptr [ebp+FFFFFF26]
:004CF1D2 33C9 xor ecx, ecx
:004CF1D4 BA65000000 mov edx, 00000065
:004CF1D9 E8DA3EF3FF call 004030B8
:004CF1DE 8D458B lea eax, dword ptr [ebp-75]
:004CF1E1 33C9 xor ecx, ecx
:004CF1E3 BA65000000 mov edx, 00000065
:004CF1E8 E8CB3EF3FF call 004030B8
* Possible StringData Ref from Code Obj ->"BlowFishDecrypt"
:004CF1ED 68C4F44C00 push 004CF4C4
:004CF1F2 56 push esi
* Reference To: KERNEL32.GetProcAddress, Ord:0158h
:004CF1F3 E8147CF3FF Call 00406E0C
:004CF1F8 8945FC mov dword ptr [ebp-04], eax
* Possible StringData Ref from Code Obj ->"EncryptStringFun1"|
:004CF1FB 68D4F44C00 push 004CF4D4
:004CF200 56 push esi
* Reference To: KERNEL32.GetProcAddress, Ord:0158h|
:004CF201 E8067CF3FF Call 00406E0C
:004CF206 8945F8 mov dword ptr [ebp-08], eax
:004CF209 837DFC00 cmp dword ptr [ebp-04], 00000000
:004CF20D 0F84C0000000 je 004CF2D3
:004CF213 837DF800 cmp dword ptr [ebp-08], 00000000
:004CF217 0F84B6000000 je 004CF2D3
* Possible StringData Ref from Code Obj ->"lxhest-EC3CABAC25C0F96DCC5AE18F874B07DC98F0E67"
->"2C26924FD"|
:004CF21D 68E8F44C00 push 004CF4E8
:004CF222 8D8526FFFFFF lea eax, dword ptr [ebp+FFFFFF26]
:004CF228 50 push eax
* Possible StringData Ref from Code Obj ->"sbipxa"|
:004CF229 6820F54C00 push 004CF520
:004CF22E 8D9514FFFFFF lea edx, dword ptr [ebp+FFFFFF14]
:004CF234 8B8300030000 mov eax, dword ptr [ebx+00000300]
:004CF23A E8453DF7FF call 00442F84
:004CF23F 8B8514FFFFFF mov eax, dword ptr [ebp+FFFFFF14]
:004CF245 8D8D18FFFFFF lea ecx, dword ptr [ebp+FFFFFF18]
:004CF24B BA10000000 mov edx, 00000010 ; 不管注册码多长,只取前16位
:004CF250 E84BD7F6FF call 0043C9A0
:004CF255 8B8518FFFFFF mov eax, dword ptr [ebp+FFFFFF18]
:004CF25B E89858F3FF call 00404AF8
:004CF260 50 push eax ; 输入是注册码
:004CF261 FF55FC call [ebp-04] ; 加密
:004CF264 84C0 test al, al
:004CF266 7413 je 004CF27B
:004CF268 8D45F4 lea eax, dword ptr [ebp-0C]
:004CF26B 8D9526FFFFFF lea edx, dword ptr [ebp+FFFFFF26] ; 结果输出
:004CF271 B965000000 mov ecx, 00000065
:004CF276 E83556F3FF call 004048B0
* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:004CF266(C)
* Possible StringData Ref from Code Obj ->"lxhest-EC3CABAC25C0F96DCC5AE18F874B07DC98F0E67"
->"2C26924FD"|
:004CF27B 68E8F44C00 push 004CF4E8
:004CF280 8D458B lea eax, dword ptr [ebp-75]
:004CF283 50 push eax
* Possible StringData Ref from Code Obj ->"sbipxa"|
:004CF284 6820F54C00 push 004CF520
:004CF289 8D9510FFFFFF lea edx, dword ptr [ebp+FFFFFF10]
:004CF28F 8B83FC020000 mov eax, dword ptr [ebx+000002FC]
:004CF295 E8EA3CF7FF call 00442F84
:004CF29A 8B8510FFFFFF mov eax, dword ptr [ebp+FFFFFF10]
:004CF2A0 E85358F3FF call 00404AF8
:004CF2A5 50 push eax ; 机器码
:004CF2A6 FF55F8 call [ebp-08] ; 加密
:004CF2A9 84C0 test al, al
:004CF2AB 7426 je 004CF2D3
:004CF2AD 8D850CFFFFFF lea eax, dword ptr [ebp+FFFFFF0C]
:004CF2B3 8D558B lea edx, dword ptr [ebp-75] ; 结果输出
:004CF2B6 B965000000 mov ecx, 00000065
:004CF2BB E8F055F3FF call 004048B0
:004CF2C0 8B850CFFFFFF mov eax, dword ptr [ebp+FFFFFF0C]
:004CF2C6 8D4DF0 lea ecx, dword ptr [ebp-10]
:004CF2C9 BA06000000 mov edx, 00000006
:004CF2CE E8E9D6F6FF call 0043C9BC
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:004CF1C6(C), :004CF20D(C), :004CF217(C), :004CF2AB(C)
:004CF2D3 56 push esi
* Reference To: KERNEL32.FreeLibrary, Ord:00C8h|
:004CF2D4 E8BB7AF3FF Call 00406D94
:004CF2D9 8B45F4 mov eax, dword ptr [ebp-0C]
:004CF2DC 8B55F0 mov edx, dword ptr [ebp-10]
:004CF2DF E86057F3FF call 00404A44
:004CF2E4 0F85B9000000 jne 004CF3A3 ; 关键比较
:004CF2EA 8BB3F0020000 mov esi, dword ptr [ebx+000002F0]
:004CF2F0 C6466403 mov [esi+64], 03
:004CF2F4 8D4668 lea eax, dword ptr [esi+68]
* Possible StringData Ref from Code Obj ->"注册成功!请保留好您的注册码,谢谢!"|
:004CF2F7 BA30F54C00 mov edx, 004CF530
:004CF2FC E89B53F3FF call 0040469C
4.对reg.dll的分析:
流程用到reg.dll,路径=D:\WINNT\system32\reg.dll,程序带的,好像是个库。
004CF1B8 |. 68 BCF44C00 push up-2.004CF4BC ; /FileName = "reg.dll"
004CF1BD |. E8 FA7CF3FF call <jmp.&KERNEL32.LoadLibraryA> ; \LoadLibraryA
载入后数据窗口0012C530显示如下加解密算法:
Base64Decode.Base64Encode.
BlowFishDecrypt.BlowFishEncrypt.
CRC32.CRCFileCheck.DecryptStringFun1.DecryptStringFun2.
DesDecrypt.DesEncrypt.EncryptStringFun1.EncryptStringFun2.FileDecrypt.FileEncrypt.
GetDllVersion.GetHardDiskId.GetMainBoardId.
MD5Encrypt.
RSADecrypt.RSAEncrypt.
SHAEncrypt.Secret16Encrypt
调用完reg.dll还不忘释放:
004CF2D3 |> \56 push esi ; /hLibModule
004CF2D4 |. E8 BB7AF3FF call <jmp.&KERNEL32.FreeLibrary> ; \FreeLibrary
程序还带了个dll:D:\WINNT\system32\smartread.dll,可能用来取得机器码。
5.加密解析
2次加密,第一次对输入的注册码,第二次对机器码,跟踪过第二次加密的值与输入的注册码无关,是定值,
说明第二次加密的跟输入的注册码无关。因此从第二次加密入手。
5.1第二次加密:对机器码的加密
004CF2A5 |. 50 push eax
004CF2A6 |. FF55 F8 call dword ptr ss:[ebp-8] ; 堆栈 ss:[0012FCB0]=10010880
入栈参数:
0012FB90 00F55E64 ASCII "0604C-5FBB0"
0012FB94 004CF520 ASCII "sbipxa"
100106C3 E8 78CAFFFF call 1000D140
这是对sbipxa下硬件访问断点找到的,跨过该call后得到32个字符,猜测MD5散列,试了下果然是。
MD5(sbipxa)= (ASCII "61146E463A46267B3489D53D8E96BB96")
取前8位=61146E46,如果有F就替换为8
100109C6 83F8 08 cmp eax,8
100109C9 7D 0F jge short 100109DA
100109CB 807C05 E4 46 cmp byte ptr ss:[ebp+eax-1C],46
100109D0 75 05 jnz short 100109D7
100109D2 C64405 E4 38 mov byte ptr ss:[ebp+eax-1C],38
100109D7 40 inc eax
100109D8 ^ EB EC jmp short 100109C6
对61146E46的填充到12位:
由上面返回来到的,填充结果:0012ACA0 01BE0D6C ASCII "61146E466114"
10001303 8A0C0E mov cl,byte ptr ds:[esi+ecx]
10001306 8D4424 24 lea eax,dword ptr ss:[esp+24]
1000130A 884C24 24 mov byte ptr ss:[esp+24],cl
1000130E 50 push eax
1000130F 6A 01 push 1
10001311 8D4C24 18 lea ecx,dword ptr ss:[esp+18]
10001315 E8 76080000 call 10001B90
1000131A 8B4C24 10 mov ecx,dword ptr ss:[esp+10]
1000131E 46 inc esi
1000131F 8379 F8 0C cmp dword ptr ds:[ecx-8],0C
10001323 ^ 7C DE jl short 10001303
逆序:0012FB0C 34 31 31 36 36 34 45 36 34 31 31 36 411664E64116
1000132F 8B7B 08 mov edi,dword ptr ds:[ebx+8]
10001332 C1E7 08 shl edi,8
10001335 897B 08 mov dword ptr ds:[ebx+8],edi
10001338 8BD7 mov edx,edi
1000133A 0FBE48 FC movsx ecx,byte ptr ds:[eax-4]
1000133E 0BCA or ecx,edx
10001340 8B53 0C mov edx,dword ptr ds:[ebx+C]
10001343 C1E2 08 shl edx,8
10001346 894B 08 mov dword ptr ds:[ebx+8],ecx
10001349 8953 0C mov dword ptr ds:[ebx+C],edx
1000134C 8BF2 mov esi,edx
1000134E 0FBE10 movsx edx,byte ptr ds:[eax]
10001351 0BD6 or edx,esi
10001353 8B73 10 mov esi,dword ptr ds:[ebx+10]
10001356 C1E6 08 shl esi,8
10001359 8953 0C mov dword ptr ds:[ebx+C],edx
1000135C 8973 10 mov dword ptr ds:[ebx+10],esi
1000135F 8BFE mov edi,esi
10001361 0FBE70 04 movsx esi,byte ptr ds:[eax+4]
10001365 0BF7 or esi,edi
10001367 40 inc eax
10001368 8973 10 mov dword ptr ds:[ebx+10],esi
1000136B 8D3C28 lea edi,dword ptr ds:[eax+ebp]
1000136E 83FF 04 cmp edi,4
10001371 ^ 7C BC jl short 1000132F
对411664E64116循环计算,结果与机器码0604C-5FBB0异或:
0012FB0C 34 31 31 36 36 34 45 36 34 31 31 36 411664E64116
A B C
100014D2 8B5C24 10 mov ebx,dword ptr ss:[esp+10]
100014D6 8B41 08 mov eax,dword ptr ds:[ecx+8] ; 取出A
100014D9 A8 01 test al,1
100014DB 74 42 je short 1000151F
100014DD 8B79 14 mov edi,dword ptr ds:[ecx+14] ; 80000062
100014E0 8B59 2C mov ebx,dword ptr ds:[ecx+2C] ; 80000000
100014E3 33F8 xor edi,eax ; A=80000062 XOR A
100014E5 8B41 0C mov eax,dword ptr ds:[ecx+C] ; 取出B
100014E8 D1EF shr edi,1 ; A/2
100014EA 0BFB or edi,ebx ; OR 80000000
100014EC A8 01 test al,1
100014EE 8979 08 mov dword ptr ds:[ecx+8],edi ; A保存回原地址12FB0C
100014F1 74 1A je short 1000150D
100014F3 8B79 18 mov edi,dword ptr ds:[ecx+18] ; 40000020
100014F6 BB 01000000 mov ebx,1
100014FB 33F8 xor edi,eax ; B XOR 40000020
100014FD 8B41 30 mov eax,dword ptr ds:[ecx+30] ; C0000000
10001500 D1EF shr edi,1 ; B/2
10001502 0BF8 or edi,eax ; B OR C0000000
10001504 895C24 10 mov dword ptr ss:[esp+10],ebx ; 赋值ebx=1
10001508 8979 0C mov dword ptr ds:[ecx+C],edi ; B保存回原地址12FB10
1000150B EB 45 jmp short 10001552
1000150D 8B79 24 mov edi,dword ptr ds:[ecx+24] ; 3FFFFFFF
10001510 D1E8 shr eax,1 ; B/2
10001512 23C7 and eax,edi ; AND 3FFFFFFF
10001514 33DB xor ebx,ebx ; 赋值ebx=0
10001516 8941 0C mov dword ptr ds:[ecx+C],eax ; 保存回原地址12FB10
10001519 895C24 10 mov dword ptr ss:[esp+10],ebx
1000151D EB 33 jmp short 10001552
1000151F 8B79 20 mov edi,dword ptr ds:[ecx+20] ; 7FFFFFFF
10001522 D1E8 shr eax,1 ; A/2
10001524 23C7 and eax,edi ; AND 7FFFFFFF
10001526 8941 08 mov dword ptr ds:[ecx+8],eax ; 保存回原地址12FB0C
10001529 8B41 10 mov eax,dword ptr ds:[ecx+10] ; 取出C
1000152C A8 01 test al,1
1000152E 74 16 je short 10001546
10001530 8B51 1C mov edx,dword ptr ds:[ecx+1C] ; 10000002
10001533 33D0 xor edx,eax ; C XOR 10000002
10001535 8B41 34 mov eax,dword ptr ds:[ecx+34] ; F0000000
10001538 D1EA shr edx,1 ; C/2
1000153A 0BD0 or edx,eax ; OR F0000000
1000153C 8951 10 mov dword ptr ds:[ecx+10],edx ; C保存回原地址12FB14
1000153F BA 01000000 mov edx,1 ; 赋值edx=1
10001544 EB 0C jmp short 10001552
10001546 8B51 28 mov edx,dword ptr ds:[ecx+28] ; 0FFFFFFF
10001549 D1E8 shr eax,1 ; C/2
1000154B 23C2 and eax,edx ; AND 0FFFFFFF
1000154D 33D2 xor edx,edx ; 赋值edx=0
1000154F 8941 10 mov dword ptr ds:[ecx+10],eax ; 保存回原地址12FB14
10001552 8AC2 mov al,dl
10001554 32C3 xor al,bl
10001556 8A5C24 0F mov bl,byte ptr ss:[esp+F]
1000155A D0E3 shl bl,1
1000155C 0AC3 or al,bl
1000155E 4E dec esi ; 循环指针
1000155F 884424 0F mov byte ptr ss:[esp+F],al ; 最后需要的值
10001563 ^ 0F85 69FFFFFF jnz 100014D2
10001569 8B4C24 18 mov ecx,dword ptr ss:[esp+18]
1000156D 5F pop edi
1000156E 5E pop esi
1000156F 5B pop ebx
10001570 8A11 mov dl,byte ptr ds:[ecx] ; 12ACD0保存了顺取机器码的一个字符
10001572 32D0 xor dl,al ; 核心运算
10001574 8811 mov byte ptr ds:[ecx],dl ; 结果保存
10001576 75 02 jnz short 1000157A
循环8次,ABC一直循环下去,得到一个最终的AL值参与机器码的异或。
返回到:
100015C4 FF52 14 call dword ptr ds:[edx+14]
...
10001670 881419 mov byte ptr ds:[ecx+ebx],dl ; 异或结果的保存,原地址
10001673 43 inc ebx
10001674 3BD8 cmp ebx,eax ; 循环次数=机器码长度
10001676 ^ 0F8C 35FFFFFF jl 100015B1
每次循环进一次call,得到一个AL值,分别为:13 FA CB 03 97 FA D9 7D 3B 2F 30
分别与机器码异或得到结果:01BE0DBC 23 CC FB 37 D4 D7 EC 3B 79 6D 30 #帖7宰?ym0.!.
然后又返回到:100109E8 E8 930BFFFF call 10001580
往下走,转换成字符串:23CCFB37D4D7EC3B796D30
10010A51 E8 EAC6FFFF call 1000D140
然后一路往下走,狂多动作,最后返回程序:
004CF2A6 |. FF55 F8 call dword ptr ss:[ebp-8]
取最后的6位:796D30
004CF2C9 |. BA 06000000 mov edx,6
004CF2CE |. E8 E9D6F6FF call up-2.0043C9BC
5.2第一次加密:对注册码的加密
004CF260 |. 50 push eax
004CF261 |. FF55 FC call dword ptr ss:[ebp-4] ; 堆栈 ss:[0012FCB4]=100137C0
入栈参数:
0012FB94 004CF520 ASCII "sbipxa"
0012EAC4 00F74240 ASCII "9876543210123456"
对注册码下硬件断点跟踪:
从00F74240拷贝数据:
第一次拷贝从00F74240到01BE0E2C,跟飞
10001AA1 F3:A5 rep movs dword ptr es:[edi],dword ptr ds:[esi] ; 停在此
01BE0E2C 39 38 37 36 35 34 33 32 31 30 31 32 33 34 35 36 9876543210123456
第二次拷贝从00F74240到01BE0D70,再次硬件断点
100139AB F3:A5 rep movs dword ptr es:[edi],dword ptr ds:[esi] ; 停在此
01BE0D70 39 38 37 36 35 34 33 32 31 30 31 32 33 34 35 36 9876543210123456
转换(01BE0D70硬件断点):
1000D0FF 8A043E mov al,byte ptr ds:[esi+edi] ; 停在此
1000D102 3C 30 cmp al,30
1000D104 7C 10 jl short 1000D116
1000D106 3C 39 cmp al,39
1000D108 7F 0C jg short 1000D116
1000D10A 8A11 mov dl,byte ptr ds:[ecx]
1000D10C 80C2 0D add dl,0D
1000D10F C0E2 04 shl dl,4
1000D112 02D0 add dl,al
1000D114 EB 12 jmp short 1000D128
1000D116 3C 41 cmp al,41
1000D118 7C 16 jl short 1000D130
1000D11A 3C 46 cmp al,46
1000D11C 7F 12 jg short 1000D130
1000D11E 8A11 mov dl,byte ptr ds:[ecx]
1000D120 C0E2 04 shl dl,4
1000D123 02D0 add dl,al
1000D125 80EA 37 sub dl,37
1000D128 46 inc esi
1000D129 8811 mov byte ptr ds:[ecx],dl ; 0012EAD8 98
1000D12B 83FE 02 cmp esi,2
1000D12E ^ 7C CF jl short 1000D0FF
取出注册码的2位.
返回:
1000D1C6 8D4424 1C lea eax,dword ptr ss:[esp+1C]
1000D1CA 50 push eax
1000D1CB 57 push edi
1000D1CC E8 1FFFFFFF call 1000D0F0 ; 调用,取注册码2位
1000D1D1 8A4C24 24 mov cl,byte ptr ss:[esp+24] ; 返回处,堆栈 ss:[0012EAD8]=98
1000D1D5 83C4 08 add esp,8
1000D1D8 880C2E mov byte ptr ds:[esi+ebp],cl ; cl=98,ds:[01BE0D50]=00
1000D1DB 46 inc esi
1000D1DC 83C7 02 add edi,2
1000D1DF 3BF3 cmp esi,ebx
1000D1E1 ^ 7C E3 jl short 1000D1C6
将01BE0D70的注册码转换保存于01BE0D50:
01BE0D50 98 76 54 32 10 12 34 56 榲T24V
返回:100139C4 E8 E797FFFF call 1000D1B0
再次转换(硬件断点01BE0D50):
10004371 8A51 FF mov dl,byte ptr ds:[ecx-1] ; 停在此,注册码98
返回:10004905 E8 56FAFFFF call 10004360
该call内容就是重排,得到:0012EAB0 32 54 76 98 56 34 12 10 2Tv榁4
增加硬件访问断点0012EAB0.
运算得到最后结果(硬件断点0012EAB0):
1000401A 8B7D 00 mov edi,dword ptr ss:[ebp] ; 停在此,987654321
1000401D 8B5E 58 mov ebx,dword ptr ds:[esi+58] ; 0012EAE8,KEY_sBOX?
10004020 33DF xor ebx,edi
10004022 8BC3 mov eax,ebx
10004024 8BCB mov ecx,ebx
10004026 C1E8 10 shr eax,10
10004029 25 FF000000 and eax,0FF
1000402E C1E9 18 shr ecx,18
10004031 8BBC86 5C040000 mov edi,dword ptr ds:[esi+eax*4+45C]
10004038 8B548E 5C mov edx,dword ptr ds:[esi+ecx*4+5C]
....
10004354 894D 00 mov dword ptr ss:[ebp],ecx ; ecx=22F277A2
10004357 895D 04 mov dword ptr ss:[ebp+4],ebx ; ebx=AB46F813
然后返回:100139D7 E8 D40CFFFF call 100046B0 ; 计算得到最后的结果
最后的结果保存于:0012FBDE 22 F2 77 A2 AB 46 F8 13
好像是BLOWFISH,对输入的注册码的前8位加密;运算取值存放在ESI(0012EAE8)以后的地址。
接下来跟踪ESI的值是否跟输入的注册码有关,是如何来的?
对sbipxa下硬件访问断点(004CF520):
拷贝(之前断下一次,读取长度,未进一步操作)
第一次拷贝,从004CF520到01BE0DBC:跟飞
10001AA1 F3:A5 rep movs dword ptr es:[edi],dword ptr ds:[esi] ; 停在此
01BE0DBC 73 62 69 70 78 61 sbipxa
第二次拷贝,从004CF520到0012EA94:
10003B4A F3:A5 rep movs dword ptr es:[edi],dword ptr ds:[esi] ; 停在此
0012EA94 73 62 69 70 78 61 sbipxa
从第二次拷贝sbipxa地址往下发现好像是对pbox,sbox的初始化:
10003B58 B9 12000000 mov ecx,12
10003B5D BE E0440210 mov esi,100244E0
10003B62 8BFA mov edi,edx
10003B64 C74424 58 12000000 mov dword ptr ss:[esp+58],12
10003B6C F3:A5 rep movs dword ptr es:[edi],dword ptr ds:[esi] ; pbox?[18]
10003B71 B9 00040000 mov ecx,400
10003B76 BE 28450210 mov esi,10024528
10003B7B F3:A5 rep movs dword ptr es:[edi],dword ptr ds:[esi] ; sbox?[4*256]
pbox[18]:
0012EAFC 88 6A 3F 24 D3 08 A3 85 2E 8A 19 13 44 73 70 03 坖?$?.?Dsp
...
0012EB3C D9 D5 16 92 1B FB 79 89 僬?鹹?筿倈
sbox[4*256]:
0012EB44 A6 0B 31 D1 AC B5 DF 98 DB 72 FD 2F B7 DF 1A D0 ?1熏颠樭r?愤
...
0012FB34 32 61 4E B7 5B E2 77 CE E3 DF 8F 57 E6 72 C3 3A 2aN穂鈝毋邚W鎟?
pbox和sbox可参考看雪精华5的Blowfish文章。
填充pbox得到key_pbox:
10003B83 33D2 xor edx,edx
10003B85 C74424 5C 04000000 mov dword ptr ss:[esp+5C],4
10003B8D 8BFA mov edi,edx
10003B8F 33D2 xor edx,edx
10003B91 8A11 mov dl,byte ptr ds:[ecx]
10003B93 C1E7 08 shl edi,8
10003B96 0BD7 or edx,edi
10003B98 41 inc ecx
10003B99 40 inc eax
10003B9A 3BC3 cmp eax,ebx
10003B9C 75 06 jnz short 10003BA4
10003B9E 33C0 xor eax,eax
10003BA0 8D4C24 18 lea ecx,dword ptr ss:[esp+18]
10003BA4 8B7C24 5C mov edi,dword ptr ss:[esp+5C]
10003BA8 4F dec edi
10003BA9 897C24 5C mov dword ptr ss:[esp+5C],edi
10003BAD ^ 75 DE jnz short 10003B8D
10003BAF 8B3E mov edi,dword ptr ds:[esi] ; 取出pbox,首地址0012EAFC
10003BB1 83C6 04 add esi,4 ; pbox下一个
10003BB4 33FA xor edi,edx ; 异或了
10003BB6 8B5424 58 mov edx,dword ptr ss:[esp+58] ; 12,即18(十进制),循环次数
10003BBA 897E FC mov dword ptr ds:[esi-4],edi ; 异或值保存回去
10003BBD 4A dec edx ; 循环指针
10003BBE 895424 58 mov dword ptr ss:[esp+58],edx
10003BC2 ^ 75 BF jnz short 10003B83
取sbipxa的ASCII码(73 62 69 70 78 61)进行循环使用,每次右移一位取8位,
得到十八组(3×6)数据:(73626970;62697078;69707861;70786173;78617362;61736269)×3
key相当于:736269706269707869707861707861737861736261736269
BF_EN加密pbox[18]:
10003BD1 8D4C24 10 lea ecx,dword ptr ss:[esp+10]
10003BD5 51 push ecx
10003BD6 8BCD mov ecx,ebp
10003BD8 E8 93000000 call 10003C70 ; BF_EN()
10003BDD 8B5424 10 mov edx,dword ptr ss:[esp+10] ; BF_EN()结果-1
10003BE1 8B4424 14 mov eax,dword ptr ss:[esp+14] ; BF_EN()结果-2
10003BE5 8916 mov dword ptr ds:[esi],edx ; 替换key_pbox[i]
10003BE7 83C6 04 add esi,4
10003BEA 47 inc edi
10003BEB 8906 mov dword ptr ds:[esi],eax ; 替换key_pbox[i+1]
10003BED 47 inc edi
10003BEE 83C6 04 add esi,4
10003BF1 83FF 12 cmp edi,12
10003BF4 ^ 72 DB jb short 10003BD1
用BF_EN加密一个全0的64位信息,用输出的结果替换key_pbox[0]和key_pbox[1],i=0;
用BF_EN加密替换后的key_pbox[i]和key_pbox[i+1],加密结果替代key_pbox[i+1]和key_pbox[i+2];
直到key_pbox全部被替换。
然后用类似的方法,替换key_sbox信息加密[4*256]:
10003C07 8D4C24 10 lea ecx,dword ptr ss:[esp+10]
10003C0B 51 push ecx
10003C0C 8BCD mov ecx,ebp
10003C0E E8 5D000000 call 10003C70
10003C13 8B5424 10 mov edx,dword ptr ss:[esp+10]
10003C17 8B4424 14 mov eax,dword ptr ss:[esp+14]
10003C1B 8916 mov dword ptr ds:[esi],edx
10003C1D 83C6 04 add esi,4
10003C20 47 inc edi
10003C21 8906 mov dword ptr ds:[esi],eax
10003C23 47 inc edi
10003C24 83C6 04 add esi,4
10003C27 81FF 00010000 cmp edi,100
10003C2D ^ 7C D8 jl short 10003C07
10003C2F 8B4424 5C mov eax,dword ptr ss:[esp+5C]
10003C33 81C3 00040000 add ebx,400
10003C39 48 dec eax
10003C3A 894424 5C mov dword ptr ss:[esp+5C],eax
10003C3E ^ 75 C3 jnz short 10003C03
这次加密key_sbox后得到的值就是上面跟踪注册码提到的ESI。
然后返回:10013931 E8 AA01FFFF call 10003AE0
再往下就是对注册码的处理(与上述跟踪注册码处理的过程连接上):
100139C4 E8 E797FFFF call 1000D1B0 ; 重排
01BE0D50 98 76 54 32 10 12 34 56 榲T24V
10004905 E8 56FAFFFF call 10004360 ; 重排
0012EAB0 32 54 76 98 56 34 12 10 2Tv榁4
10004914 E8 F7F6FFFF call 10004010 ; 加密
5.3比较
对2次加密结果的比较,注册码加密的是16字节64位,机器码加密取后面6个字符是12字节24位。
004CF2D9 |. 8B45 F4 mov eax,dword ptr ss:[ebp-C]
004CF2DC |. 8B55 F0 mov edx,dword ptr ss:[ebp-10]
004CF2DF |. E8 6057F3FF call up-2.00404A44 ; BIJIAO
004CF2E4 |. 0F85 B9000000 jnz up-2.004CF3A3
EAX:00F55E64 22 F2 77 A2 AB 46 F8 13 "騱F?...
EDX:00F5185C 37 39 36 44 33 30 00 00 796D30..
6.算法总结
对注册码的加密:
采用Blowfish加密,key=736269706269707869707861707861737861736261736269,得到比较值之一。
对机器码的加密:
MD5(sbipxa),取前8位+前4位扩充到12位(有F的替换成8),逆序重排后参与循环计算得到AL值(1个字节),根据机器码长度产生同样数目的AL,然后与机器码XOR,得到值,取后12位作为比较值之一。
如果两者的加密结果一样的话就注册成功。
7.后记
很遗憾,功力不够,没能反推出注册码。
看雪论坛上只有一个计算Blowfish的工具cryptocal.exe,可是加密结果跟这个程序加密的值不一样,不晓得是不是字节跟字符没有转换的原因还是其他的。看雪精华5里有Blowfish加密解密的源代码,可惜我不会用。
错误与不足之处请指正!
如果有提供Blowfish计算工具的(最好输入格式为字节),不胜感谢!