【脱文标题】 手动脱壳入门MoleBox 2.x 和Patch IAT加密
【使用工具】 Peid,Ollydbg,ImportREC1.6f,Loadpe
【脱文作者】 lhg
【脱壳声明】 我是一只小菜鸟，偶得一点心得，愿与大家分享：)
【脱壳内容】
前几天,在FCG论坛看到Compare It!3.8的破解补丁,想看看它是如何PATCH.
首先Peid查壳，为MoleBox 2.x.x -> Mole Studio，OD载入运行，无任何异常，判断其为压缩壳。
005592EC w> 60 pushad
005592ED E8 4F000000 call wincmp3.00559341
005592F2 25 72A89805 and eax,598A872
005592F7 A5 movs dword ptr es:[edi],dword ptr ds:[es>
005592F8 304460 FB xor byte ptr ds:[eax-5],al
005592FC D86E 2F fsubr dword ptr ds:[esi+2F]
005592FF 49 dec ecx
00559300 AD lods dword ptr ds:[esi]
00559301 20C9 and cl,cl
00559303 ^ E2 8A loopd short wincmp3.0055928F
00559305 0AD9 or bl,cl
F7步入几次后变成如下代码：
00559290 E8 DBFBFFFF call wincmp3.00558E70
00559295 58 pop eax
00559296 E8 75030000 call wincmp3.00559610
0055929B 58 pop eax
0055929C 894424 1C mov dword ptr ss:[esp+1C],eax
005592A0 61 popad //在此下断 eax=0048ED77
005592A1 FFE0 jmp eax //飞向光明之巅
0048ED77 55 push ebp
0048ED78 8BEC mov ebp,esp
0048ED7A 6A FF push -1
0048ED7C 68 B8774E00 push wincmp3.004E77B8
0048ED81 68 6C374900 push wincmp3.0049376C
0048ED86 64:A1 00000000 mov eax,dword ptr fs:[0]
0048ED8C 50 push eax
0048ED8D 64:8925 00000000 mov dword ptr fs:[0],esp
脱壳后发现程序不能运行,这时需要用Imprec修复引入函数表(Import Table)
在Oep处填8ED77,点IT自动搜索,然后点获输入信息,有23个指针没有修复。
2. Patch IAT 躲开IAT加密
加密处理后的IAT表(如下)
(选择第一个被加密的函数地址在 004D6240,重启OD,对[004d6240]下内存写入断点
0055DBA4 66:8901 mov word ptr ds:[ecx],ax //断下,F9
0055DBA7 8B45 F8 mov eax,dword ptr ss:[ebp-8]
0055DBAA 40 inc eax
0055DBAB 40 inc eax
0055DBAC 8945 F8 mov dword ptr ss:[ebp-8],eax
0055DBC2 66:8901 mov word ptr ds:[ecx],ax //断下,F9 几次后
0055DBC5 8B45 F8 mov eax,dword ptr ss:[ebp-8]
0055DBC8 40 inc eax
0055DBC9 40 inc eax
0055F093 8B4D E8 mov ecx,dword ptr ss:[ebp-18]
0055F096 8901 mov dword ptr ds:[ecx],eax //断下 ; KERNEL32.UnmapViewOfFile
0055F098 EB 2C jmp short wincmp3.0055F0C6
eax=77E77179 (KERNEL32.UnmapViewOfFile)
ds:[004D6240]=000F9708
//到这里eax为正确的IAT,放入[004d6240]
//在看看它是如何加密,继续F8,到0055F0C6
0055F0C6 8B55 F4 mov edx,dword ptr ss:[ebp-C]
0055F0C9 81E2 FF000000 and edx,0FF
0055F0CF 85D2 test edx,edx
0055F0D1 74 17 je short wincmp3.0055F0EA //判断是否加密,改为JMP
0055F0D3 8B45 E4 mov eax,dword ptr ss:[ebp-1C] //为了看它如何加密,继续走
0055F0D6 50 push eax
0055F0D7 8B0D F89A5600 mov ecx,dword ptr ds:[569AF8] ; wincmp3.00569AFC
0055F0DD 51 push ecx
0055F0DE 8B55 E8 mov edx,dword ptr ss:[ebp-18] ; wincmp3.004D6240
0055F0E1 52 push edx
0055F0E2 E8 C9060000 call wincmp3.0055F7B0 //加密call,跟进
0055F0E7 83C4 0C add esp,0C
0055F0EA ^ E9 5BFFFFFF jmp wincmp3.0055F04A
0055F0EF 8B45 EC mov eax,dword ptr ss:[ebp-14]
0055F0F2 A3 F89A5600 mov dword ptr ds:[569AF8],eax
0055F0F7 8B4D FC mov ecx,dword ptr ss:[ebp-4]
0055F0FA 6BC9 14 imul ecx,ecx,14
0055F0FD 8B55 08 mov edx,dword ptr ss:[ebp+8]
0055F100 C7440A 04 FFFFFF>mov dword ptr ds:[edx+ecx+4],-1
0055F108 ^ E9 12FEFFFF jmp wincmp3.0055EF1F
0055F10D 8BE5 mov esp,ebp
0055F10F 5D pop ebp
0055F110 C3 retn
在Oep处填0008ED77,点IT自动搜索,然后点获输入信息,全部有效，修复脱壳文件，正常运行。
0055F7B0 55 push ebp
0055F7B1 8BEC mov ebp,esp
0055F7B3 83EC 10 sub esp,10
0055F7B6 C745 FC 00000000 mov dword ptr ss:[ebp-4],0
0055F7BD 833D 88F05600 00 cmp dword ptr ds:[56F088],0
0055F7C4 75 0A jnz short wincmp3.0055F7D0
0055F7C6 B9 0A0000EF mov ecx,EF00000A
0055F7CB E8 34200000 call wincmp3.00561804
0055F7D0 8B45 08 mov eax,dword ptr ss:[ebp+8] //壳的地址; wincmp3.004D6240
0055F7D3 8B08 mov ecx,dword ptr ds:[eax]
0055F7D5 51 push ecx
0055F7D6 8B0D 88F05600 mov ecx,dword ptr ds:[56F088]
0055F7DC E8 DA470000 call wincmp3.00563FBB
0055F7E1 8945 F8 mov dword ptr ss:[ebp-8],eax
0055F7E4 837D F8 00 cmp dword ptr ss:[ebp-8],0
0055F7E8 74 45 je short wincmp3.0055F82F
0055F7EA 8D55 F0 lea edx,dword ptr ss:[ebp-10]
0055F7ED 52 push edx
0055F7EE 6A 04 push 4
0055F7F0 6A 04 push 4
0055F7F2 8B45 08 mov eax,dword ptr ss:[ebp+8]
0055F7F5 50 push eax
0055F7F6 FF15 4CA95600 call dword ptr ds:[56A94C] ; KERNEL32.VirtualProtect
0055F7FC 85C0 test eax,eax
0055F7FE 75 0A jnz short wincmp3.0055F80A
0055F800 B9 0B0000EF mov ecx,EF00000B
0055F805 E8 FA1F0000 call wincmp3.00561804
0055F80A 8B4D 08 mov ecx,dword ptr ss:[ebp+8]
0055F80D 8B55 F8 mov edx,dword ptr ss:[ebp-8]
0055F810 8B02 mov eax,dword ptr ds:[edx]
0055F812 8901 mov dword ptr ds:[ecx],eax //将壳的地址替换 正确的IAT
//eax=00563492 (wincmp3.00563492)
//ds:[004D6240]=77E77179 (KERNEL32.UnmapViewOfFile)
//我们必需让EAX是正确的指针。我们看到0055F7D0 处EAX被赋值，而且当时的EAX是正确指针。
//故0055F7D0处
//0055F7D0 8B45 08 mov eax,dword ptr ss:[ebp+8]
//修改如下:
//0055F7D0 8BCD mov eax,eax
//0055F7D2 90 nop
0055F814 8D4D F4 lea ecx,dword ptr ss:[ebp-C]
0055F817 51 push ecx
0055F818 8B55 F0 mov edx,dword ptr ss:[ebp-10]
0055F81B 52 push edx
0055F81C 6A 04 push 4
0055F81E 8B45 08 mov eax,dword ptr ss:[ebp+8]
0055F821 50 push eax
0055F822 FF15 4CA95600 call dword ptr ds:[56A94C] ; KERNEL32.VirtualProtect
0055F828 C745 FC 01000000 mov dword ptr ss:[ebp-4],1
0055F82F 8B45 FC mov eax,dword ptr ss:[ebp-4]
0055F832 8BE5 mov esp,ebp
0055F834 5D pop ebp
0055F835 C3 retn
加密处理后的IAT表:
004D6240 00563492 wincmp3.00563492 //被加密
004D6270 005628D4 wincmp3.005628D4 //被加密
004D62B0 005634B9 wincmp3.005634B9 //被加密
004D6324 00563DC1 wincmp3.00563DC1 //被加密
004D635C 00562CDA wincmp3.00562CDA //被加密
004D6364 00562D76 wincmp3.00562D76 //被加密
004D6368 00562F3F wincmp3.00562F3F //被加密
004D6370 00562FA2 wincmp3.00562FA2 //被加密
004D63A8 00562B71 wincmp3.00562B71 //被加密
004D63B0 00563453 wincmp3.00563453 //被加密
004D63BC 0056301E wincmp3.0056301E //被加密
004D63D4 00563282 wincmp3.00563282 //被加密
004D63EC 00562FE6 wincmp3.00562FE6 //被加密
004D6400 00562995 wincmp3.00562995 //被加密
004D6404 005636C1 wincmp3.005636C1 //被加密
004D6408 00563715 wincmp3.00563715 //被加密
004D640C 005636EE wincmp3.005636EE //被加密
004D6450 005635AD wincmp3.005635AD //被加密
004D6458 00563384 wincmp3.00563384 //被加密
004D645C 00563096 wincmp3.00563096 //被加密
004D6460 00562F18 wincmp3.00562F18 //被加密
004D6468 00562B23 wincmp3.00562B23 //被加密
004D6470 00563D7A wincmp3.00563D7A //被加密
[招生]科锐逆向工程师培训(2024年11月15日实地，远程教学同时开班, 第51期)
