[原创]SKYPE中的 anti-debug 分析-软件逆向-看雪-安全社区|安全招聘|kanxue.com

[原创]SKYPE中的 anti-debug 分析

发表于: 2006-2-17 09:15 9702

[原创]SKYPE中的 anti-debug 分析

blackeyes

2006-2-17 09:15

9702

SKYPE中的 anti-debug 分析

软件名称: skype

实例下载: http://www.skype.com/download

作者: blackeyes

声明: skype 是 freeware, 没有什么要 PJ的, 只是分析它的anti-debug

1. 基本信息

入口点(OEP):       005E7A28

引入表(I T):       00B8F000-00B8F21B ( size: 021C )

引入地址表(IAT): 00B8F21C-00B8FD38 ( size: 0B1C )

PeID结果: Borland Delphi 6.0 - 7.0 [Overlay]

2. 调试器检测, CODE 解码, 解析第二份IAT

// OD 载入后停在这里 005E7A28
005E7A28 > $ /EB 57             JMP SHORT Skype.005E7A81

005E7A81 > \E8 26010000       CALL Skype.005E7BAC                               ; // detect softice (第 1 处)
005E7A86 .  84C0                TEST AL,AL
005E7A88 .  74 1C             JE SHORT Skype.005E7AA6
005E7A8A .  6A 00             PUSH 0                                           ; /Style = MB_OK|MB_APPLMODAL
005E7A8C .  FF35 482FB800       PUSH DWORD PTR DS:[B82F48]                      ; |Title = "Skype"
005E7A92 .  FF35 4C2FB800       PUSH DWORD PTR DS:[B82F4C]                      ; |Text = "Error: Skype is not compatible with debuggers like SoftICE .."
005E7A98 .  6A 00             PUSH 0                                           ; |hOwner = NULL
005E7A9A .  E8 9910E2FF       CALL <JMP.&user32.MessageBoxA>                   ; \MessageBoxA
005E7A9F .  6A 01             PUSH 1                                           ; /ExitCode = 1
005E7AA1 .  E8 5A04E2FF       CALL <JMP.&kernel32.ExitProcess>                ; \ExitProcess
005E7AA6 >  BA 011E1600       MOV EDX,161E01
005E7AAB .  81C2 A38BA100       ADD EDX,Skype.00A18BA3                      ; // EDX = 00B7A9A4
005E7AB1 .  52                PUSH EDX
005E7AB2 .  EB 10             JMP SHORT Skype.005E7AC4
005E7AB4 .  BF 287A5E00       MOV EDI,Skype.<ModuleEntryPoint>
005E7AB9 .  B9 C47A5E00       MOV ECX,Skype.005E7AC4
005E7ABE .  29F9                SUB ECX,EDI
005E7AC0 .  31C0                XOR EAX,EAX
005E7AC2 .  F3:AA             REP STOS BYTE PTR ES:[EDI]
005E7AC4 >  E8 CF3F0100       CALL Skype.005FBA98
005E7AC9 .  E8 AAFEFFFF       CALL Skype.005E7978
005E7ACE .  C3                RETN                                           ; // return 00B7A9A4

00B7A9A4 .  55                PUSH EBP    ; 感觉这儿才是程序入口点
00B7A9A5 .  8BEC                MOV EBP,ESP
00B7A9A7 .  B9 20000000       MOV ECX,20
00B7A9AC >  6A 00             PUSH 0
00B7A9AE .  6A 00             PUSH 0
00B7A9B0 .  49                DEC ECX
00B7A9B1 .^ 75 F9             JNZ SHORT Skype.00B7A9AC
00B7A9B3 .  53                PUSH EBX
00B7A9B4 .  56                PUSH ESI
00B7A9B5 .  57                PUSH EDI
00B7A9B6 .  B8 749FB700       MOV EAX,Skype.00B79F74
00B7A9BB .  E8 6CD088FF       CALL Skype.00407A2C                            ; // *** Init CALL ****
00B7A9C0 .  BF 78E6B800       MOV EDI,Skype.00B8E678
00B7A9C5 .  33C0                XOR EAX,EAX
00B7A9C7 .  55                PUSH EBP
00B7A9C8 .  68 1BBAB700       PUSH Skype.00B7BA1B
00B7A9CD .  64:FF30             PUSH DWORD PTR FS:[EAX]
00B7A9D0 .  64:8920             MOV DWORD PTR FS:[EAX],ESP
00B7A9D3 .  A1 90B2B800       MOV EAX,DWORD PTR DS:[B8B290]
00B7A9D8 .  C600 01             MOV BYTE PTR DS:[EAX],1
00B7A9DB .  6A 00             PUSH 0
00B7A9DD .  E8 661D8AFF       CALL <JMP.&ole32.OleInitialize>
00B7A9E2 .  E8 3DB6A6FF       CALL Skype.005E6024                               ; // detect debug (第 2 处)
00B7A9E7 .  84C0                TEST AL,AL
00B7A9E9 .  74 1A             JE SHORT Skype.00B7AA05
00B7A9EB .  6A 00             PUSH 0                                           ; /Style = MB_OK|MB_APPLMODAL
00B7A9ED .  68 30BAB700       PUSH Skype.00B7BA30                            ; |Title = "Skype"
00B7A9F2 .  68 38BAB700       PUSH Skype.00B7BA38                            ; |Text = "Skype is not compatible with system debuggers like SoftICE."
00B7A9F7 .  6A 00             PUSH 0                                           ; |hOwner = NULL
00B7A9F9 .  E8 32E188FF       CALL <JMP.&user32.MessageBoxA>                   ; \MessageBoxA
00B7A9FE .  6A 00             PUSH 0                                           ; /ExitCode = 0
00B7AA00 .  E8 FBD488FF       CALL <JMP.&kernel32.ExitProcess>                ; \ExitProcess
00B7AA05 >  B9 7CBAB700       MOV ECX,Skype.00B7BA7C                         ;  ASCII "Starting  .."
00B7AA0A .  BA 94BAB700       MOV EDX,Skype.00B7BA94                         ;  ASCII "Skype.main"

// Init call
00407A2C  /$  53                PUSH EBX
00407A2D  |.  8BD8                MOV EBX,EAX
00407A2F  |.  33C0                XOR EAX,EAX
00407A31  |.  A3 A4C0B700       MOV DWORD PTR DS:[B7C0A4],EAX
00407A36  |.  6A 00             PUSH 0                                           ; /pModule = NULL
00407A38  |.  E8 2BFFFFFF       CALL <JMP.&kernel32.GetModuleHandleA>          ; \GetModuleHandleA
00407A3D  |.  A3 68C6B800       MOV DWORD PTR DS:[B8C668],EAX
00407A42  |.  A1 68C6B800       MOV EAX,DWORD PTR DS:[B8C668]
00407A47  |.  A3 B0C0B700       MOV DWORD PTR DS:[B7C0B0],EAX
00407A4C  |.  33C0                XOR EAX,EAX
00407A4E  |.  A3 B4C0B700       MOV DWORD PTR DS:[B7C0B4],EAX
00407A53  |.  33C0                XOR EAX,EAX
00407A55  |.  A3 B8C0B700       MOV DWORD PTR DS:[B7C0B8],EAX
00407A5A  |.  E8 C1FFFFFF       CALL Skype.00407A20
00407A5F  |.  BA ACC0B700       MOV EDX,Skype.00B7C0AC
00407A64  |.  8BC3                MOV EAX,EBX
00407A66  |.  E8 95D2FFFF       CALL Skype.00404D00                            ; // 都在这里 CALL init
00407A6B  |.  5B                POP EBX
00407A6C  \.  C3                RETN

00404D00  /$  C705 14C0B800 F01240>MOV DWORD PTR DS:[B8C014],<JMP.&kernel32.RaiseException>
00404D0A  |.  C705 18C0B800 001340>MOV DWORD PTR DS:[B8C018],<JMP.&kernel32.RtlUnwind>
00404D14  |.  A3 40C6B800       MOV DWORD PTR DS:[B8C640],EAX
00404D19  |.  33C0                XOR EAX,EAX
00404D1B  |.  A3 44C6B800       MOV DWORD PTR DS:[B8C644],EAX
00404D20  |.  8915 48C6B800       MOV DWORD PTR DS:[B8C648],EDX
00404D26  |.  8B42 04             MOV EAX,DWORD PTR DS:[EDX+4]
00404D29  |.  A3 30C0B800       MOV DWORD PTR DS:[B8C030],EAX
00404D2E  |.  E8 A5FEFFFF       CALL Skype.00404BD8
00404D33  |.  C605 38C0B800 00    MOV BYTE PTR DS:[B8C038],0
00404D3A  |.  E8 51FFFFFF       CALL Skype.00404C90    ; // Delphi 的程序好象都是这样
00404D3F  \.  C3                RETN

00404C90 $  55                PUSH EBP
00404C91 .  8BEC                MOV EBP,ESP
00404C93 .  83C4 F8             ADD ESP,-8
00404C96 .  53                PUSH EBX
00404C97 .  56                PUSH ESI
00404C98 .  57                PUSH EDI
00404C99 .  BF 38C6B800       MOV EDI,Skype.00B8C638
00404C9E .  8B47 08             MOV EAX,DWORD PTR DS:[EDI+8]
00404CA1 .  85C0                TEST EAX,EAX
00404CA3 .  74 54             JE SHORT Skype.00404CF9
00404CA5 .  8B30                MOV ESI,DWORD PTR DS:[EAX]
00404CA7 .  33DB                XOR EBX,EBX
00404CA9 .  8B40 04             MOV EAX,DWORD PTR DS:[EAX+4]
00404CAC .  8945 FC             MOV DWORD PTR SS:[EBP-4],EAX
00404CAF .  33C0                XOR EAX,EAX
00404CB1 .  55                PUSH EBP
00404CB2 .  68 E54C4000       PUSH Skype.00404CE5
00404CB7 .  64:FF30             PUSH DWORD PTR FS:[EAX]
00404CBA .  64:8920             MOV DWORD PTR FS:[EAX],ESP
00404CBD .  3BF3                CMP ESI,EBX
00404CBF .  7E 1A             JLE SHORT Skype.00404CDB
00404CC1 >  8B45 FC             MOV EAX,DWORD PTR SS:[EBP-4]
00404CC4 .  8B04D8             MOV EAX,DWORD PTR DS:[EAX+EBX*8]
00404CC7 .  8945 F8             MOV DWORD PTR SS:[EBP-8],EAX
00404CCA .  43                INC EBX
00404CCB .  895F 0C             MOV DWORD PTR DS:[EDI+C],EBX
00404CCE .  837D F8 00          CMP DWORD PTR SS:[EBP-8],0
00404CD2 .  74 03             JE SHORT Skype.00404CD7
00404CD4 .  FF55 F8             CALL DWORD PTR SS:[EBP-8]                      ; // Call each init Func, 其中 00B75AF0 最关键,
00404CD7 >  3BF3                CMP ESI,EBX
00404CD9 .^ 7F E6             JG SHORT Skype.00404CC1
00404CDB >  33C0                XOR EAX,EAX
00404CDD .  5A                POP EDX
00404CDE .  59                POP ECX
00404CDF .  59                POP ECX
00404CE0 .  64:8910             MOV DWORD PTR FS:[EAX],EDX
00404CE3 .  EB 14             JMP SHORT Skype.00404CF9
00404CE5 .^ E9 3AF9FFFF       JMP Skype.00404624
00404CEA .  E8 31FFFFFF       CALL Skype.00404C20
00404CEF .  E8 08FDFFFF       CALL Skype.004049FC
00404CF4 .  E8 57FDFFFF       CALL Skype.00404A50
00404CF9 >  5F                POP EDI
00404CFA .  5E                POP ESI
00404CFB .  5B                POP EBX
00404CFC .  59                POP ECX
00404CFD .  59                POP ECX
00404CFE .  5D                POP EBP
00404CFF .  C3                RETN

检查调试器的两处, 下 CreateFileA, CreateFileW 断点, 很快就可以跟到, 不过它不检测OLLYDBG.

3. 最关键的一个 Init CALL  00B75AF0-00B75EB1

// 对 00724F70-00B70F70 (size 0044C000) 解码, 并解析第二份 IAT
//  第二份 IAT:       00A09F70-00A0A38C, size: 041C
//  00B75AF0 返回后, 内存中全是明文.

00B75AF0  /> /55                PUSH EBP
00B75AF1  |. |8BEC                MOV EBP,ESP
00B75AF3  |. |83C4 A0             ADD ESP,-60
00B75AF6  |. |33C0                XOR EAX,EAX
00B75AF8  |. |8945 A8             MOV DWORD PTR SS:[EBP-58],EAX
00B75AFB  |. |8945 A4             MOV DWORD PTR SS:[EBP-5C],EAX
00B75AFE  |. |8945 A0             MOV DWORD PTR SS:[EBP-60],EAX
00B75B01  |. |8945 AC             MOV DWORD PTR SS:[EBP-54],EAX
00B75B04  |. |33C0                XOR EAX,EAX
00B75B06  |. |55                PUSH EBP
00B75B07  |. |68 A75EB700       PUSH Skype.00B75EA7
00B75B0C  |. |64:FF30             PUSH DWORD PTR FS:[EAX]
00B75B0F  |. |64:8920             MOV DWORD PTR FS:[EAX],ESP
00B75B12  |. |A1 18BAB800       MOV EAX,DWORD PTR DS:[B8BA18]
00B75B17  |. |C700 09000000       MOV DWORD PTR DS:[EAX],9
00B75B1D  |. |B8 287A5E00       MOV EAX,Skype.<ModuleEntryPoint>
00B75B22  |. |8945 D4             MOV DWORD PTR SS:[EBP-2C],EAX
00B75B25  |.  C745 D0 F4000000    MOV DWORD PTR SS:[EBP-30],0F4
00B75B2C  |.  8D45 FC             LEA EAX,DWORD PTR SS:[EBP-4]
00B75B2F  |.  50                PUSH EAX                                        ; /pOldProtect
00B75B30  |.  6A 40             PUSH 40                                        ; |NewProtect = PAGE_EXECUTE_READWRITE
00B75B32  |.  8B45 D0             MOV EAX,DWORD PTR SS:[EBP-30]                   ; |
00B75B35  |.  50                PUSH EAX                                        ; |Size
00B75B36  |.  8B45 D4             MOV EAX,DWORD PTR SS:[EBP-2C]                   ; |
00B75B39  |.  50                PUSH EAX                                        ; |Address
00B75B3A  |.  E8 192789FF       CALL <JMP.&kernel32.VirtualProtect>             ; \VirtualProtect
00B75B3F  |.  85C0                TEST EAX,EAX
00B75B41  |.  75 0A             JNZ SHORT Skype.00B75B4D
00B75B43  |.  B8 BC5EB700       MOV EAX,Skype.00B75EBC                         ;  ASCII "0ut of memory"
00B75B48  |.  E8 2BFAFFFF       CALL Skype.00B75578
00B75B4D  |>  8B45 D4             MOV EAX,DWORD PTR SS:[EBP-2C]
00B75B50  |.  33C9                XOR ECX,ECX
00B75B52  |.  8B55 D0             MOV EDX,DWORD PTR SS:[EBP-30]
00B75B55  |.  E8 96DD88FF       CALL Skype.004038F0    ; 将 OEP 处开始的一小段代码清 0, 防止解码后的 DUMP
00B75B5A  |.  8D45 FC             LEA EAX,DWORD PTR SS:[EBP-4]
00B75B5D  |.  50                PUSH EAX                                        ; /pOldProtect
00B75B5E  |.  6A 20             PUSH 20                                        ; |NewProtect = PAGE_EXECUTE_READ
00B75B60  |.  8B45 D0             MOV EAX,DWORD PTR SS:[EBP-30]                   ; |
00B75B63  |.  50                PUSH EAX                                        ; |Size
00B75B64  |.  8B45 D4             MOV EAX,DWORD PTR SS:[EBP-2C]                   ; |
00B75B67  |.  50                PUSH EAX                                        ; |Address
00B75B68  |.  E8 EB2689FF       CALL <JMP.&kernel32.VirtualProtect>             ; \VirtualProtect
00B75B6D  |.  85C0                TEST EAX,EAX
00B75B6F  |.  75 0A             JNZ SHORT Skype.00B75B7B
00B75B71  |.  B8 BC5EB700       MOV EAX,Skype.00B75EBC                         ;  ASCII "0ut of memory"
00B75B76  |.  E8 FDF9FFFF       CALL Skype.00B75578
00B75B7B  |>  C605 0C5FB800 01    MOV BYTE PTR DS:[B85F0C],1
00B75B82  |.  6A 04             PUSH 4                                           ; /Protect = PAGE_READWRITE
00B75B84  |.  68 00100000       PUSH 1000                                        ; |AllocationType = MEM_COMMIT
00B75B89  |.  A1 605FB800       MOV EAX,DWORD PTR DS:[B85F60]                   ; |
00B75B8E  |.  50                PUSH EAX                                        ; |Size => 44C000 (4505600.)
00B75B8F  |.  6A 00             PUSH 0                                           ; |Address = NULL
00B75B91  |.  E8 B22689FF       CALL <JMP.&kernel32.VirtualAlloc>                ; \VirtualAlloc,  分配 Memory 用来解码
00B75B96  |.  A3 4CE1B800       MOV DWORD PTR DS:[B8E14C],EAX
00B75B9B  |.  833D 4CE1B800 00    CMP DWORD PTR DS:[B8E14C],0
00B75BA2  |.  75 0A             JNZ SHORT Skype.00B75BAE
00B75BA4  |.  B8 D45EB700       MOV EAX,Skype.00B75ED4                         ;  ASCII "Not enough memory!"
00B75BA9  |.  E8 CAF9FFFF       CALL Skype.00B75578
00B75BAE  |>  B8 684F7200       MOV EAX,Skype.00724F68    ; 从这儿开始是解码的CODE, 很简单, 就一个XOR, 只是XOR的值是一直在变.
00B75BB3  |.  BA 684F7200       MOV EDX,Skype.00724F68
00B75BB8  |.  0302                ADD EAX,DWORD PTR DS:[EDX]
00B75BBA  |.  8945 CC             MOV DWORD PTR SS:[EBP-34],EAX
00B75BBD  |.  33C0                XOR EAX,EAX
00B75BBF  |.  8945 F8             MOV DWORD PTR SS:[EBP-8],EAX
00B75BC2  |.  E9 83000000       JMP Skype.00B75C4A
00B75BC7  |>  8B45 F8             /MOV EAX,DWORD PTR SS:[EBP-8]

...省略一些CODE

00B75C3B  |.  8345 EC 71          ||ADD DWORD PTR SS:[EBP-14],71
00B75C3F  |.  FF45 E8             ||INC DWORD PTR SS:[EBP-18]
00B75C42  |.  FF4D C8             ||DEC DWORD PTR SS:[EBP-38]
00B75C45  |.^ 75 D0             |\JNZ SHORT Skype.00B75C17
00B75C47  |>  FF45 F8             |INC DWORD PTR SS:[EBP-8]
00B75C4A  |>  8B45 F8             MOV EAX,DWORD PTR SS:[EBP-8]
00B75C4D  |.  8D0480             |LEA EAX,DWORD PTR DS:[EAX+EAX*4]
00B75C50  |.  833C85 105FB800 00 |CMP DWORD PTR DS:[EAX*4+B85F10],0
00B75C58  |.^ 0F87 69FFFFFF       \JA Skype.00B75BC7    ; 解码的CODE到这儿为止

00B75C5E  |.  33C0                XOR EAX,EAX    ; 从这儿起开始解析一份内部的IAT
00B75C60  |.  8945 E4             MOV DWORD PTR SS:[EBP-1C],EAX
00B75C63  |.  33C0                XOR EAX,EAX
00B75C65  |.  8945 DC             MOV DWORD PTR SS:[EBP-24],EAX
00B75C68  |.  C745 E8 01000000    MOV DWORD PTR SS:[EBP-18],1
00B75C6F  |>  8B45 E8             /MOV EAX,DWORD PTR SS:[EBP-18]

...省略一些CODE

00B75D51  |>  8B45 E0             |MOV EAX,DWORD PTR SS:[EBP-20]
00B75D54  |.  0145 DC             |ADD DWORD PTR SS:[EBP-24],EAX
00B75D57  |.  8B45 E8             |MOV EAX,DWORD PTR SS:[EBP-18]
00B75D5A  |.  8D0440             |LEA EAX,DWORD PTR DS:[EAX+EAX*2]
00B75D5D  |.  8B0485 705FB800    |MOV EAX,DWORD PTR DS:[EAX*4+B85F70]
00B75D64  |.  0305 4CE1B800       |ADD EAX,DWORD PTR DS:[B8E14C]
00B75D6A  |.  8B55 E0             |MOV EDX,DWORD PTR SS:[EBP-20]
00B75D6D  |.  8910                |MOV DWORD PTR DS:[EAX],EDX
00B75D6F  |>  FF45 E8             |INC DWORD PTR SS:[EBP-18]
00B75D72  |.  817D E8 09010000    |CMP DWORD PTR SS:[EBP-18],109
00B75D79  |.^ 0F85 F0FEFFFF       \JNZ Skype.00B75C6F

00B75D7F  |.  8D45 FC             LEA EAX,DWORD PTR SS:[EBP-4]
00B75D82  |.  50                PUSH EAX                                        ; /pOldProtect
00B75D83  |.  6A 04             PUSH 4                                           ; |NewProtect = PAGE_READWRITE
00B75D85  |.  A1 605FB800       MOV EAX,DWORD PTR DS:[B85F60]                   ; |
00B75D8A  |.  50                PUSH EAX                                        ; |Size => 44C000 (4505600.)
00B75D8B  |.  8B45 CC             MOV EAX,DWORD PTR SS:[EBP-34]                   ; |
00B75D8E  |.  50                PUSH EAX                                        ; |Address
00B75D8F  |.  E8 C42489FF       CALL <JMP.&kernel32.VirtualProtect>             ; \VirtualProtect
00B75D94  |.  85C0                TEST EAX,EAX
00B75D96  |.  75 51             JNZ SHORT Skype.00B75DE9
00B75D98  |.  68 405FB700       PUSH Skype.00B75F40                            ;  ASCII "error 9920 ("
00B75D9D  |.  8D4D A4             LEA ECX,DWORD PTR SS:[EBP-5C]
00B75DA0  |.  B2 08             MOV DL,8
00B75DA2  |.  A1 605FB800       MOV EAX,DWORD PTR DS:[B85F60]
00B75DA7  |.  E8 E09791FF       CALL Skype.0048F58C
00B75DAC  |.  FF75 A4             PUSH DWORD PTR SS:[EBP-5C]
00B75DAF  |.  68 585FB700       PUSH Skype.00B75F58
00B75DB4  |.  E8 572289FF       CALL <JMP.&kernel32.GetLastError>                ; GetLastError
00B75DB9  |.  33D2                XOR EDX,EDX
00B75DBB  |.  52                PUSH EDX                                        ; /Arg2 => 00000000
00B75DBC  |.  50                PUSH EAX                                        ; |Arg1
00B75DBD  |.  8D45 A0             LEA EAX,DWORD PTR SS:[EBP-60]                   ; |
00B75DC0  |.  E8 9B5189FF       CALL Skype.0040AF60                            ; \Skype.0040AF60
00B75DC5  |.  FF75 A0             PUSH DWORD PTR SS:[EBP-60]
00B75DC8  |.  68 645FB700       PUSH Skype.00B75F64
00B75DCD  |.  8D45 A8             LEA EAX,DWORD PTR SS:[EBP-58]
00B75DD0  |.  BA 05000000       MOV EDX,5
00B75DD5  |.  E8 52F688FF       CALL Skype.0040542C
00B75DDA  |.  8B45 A8             MOV EAX,DWORD PTR SS:[EBP-58]
00B75DDD  |.  E8 46468CFF       CALL Skype.0043A428
00B75DE2  |.  6A 00             PUSH 0                                           ; /ExitCode = 0
00B75DE4  |.  E8 172189FF       CALL <JMP.&kernel32.ExitProcess>                ; \ExitProcess
00B75DE9  |>  8B55 CC             MOV EDX,DWORD PTR SS:[EBP-34]
00B75DEC  |.  A1 4CE1B800       MOV EAX,DWORD PTR DS:[B8E14C]
00B75DF1  |.  8B0D 605FB800       MOV ECX,DWORD PTR DS:[B85F60]                   ;  Skype.0044C000
00B75DF7  |.  E8 14D388FF       CALL Skype.00403110    ;
00B75DFC  |.  68 00800000       PUSH 8000                                        ; /FreeType = MEM_RELEASE
00B75E01  |.  6A 00             PUSH 0                                           ; |Size = 0
00B75E03  |.  A1 4CE1B800       MOV EAX,DWORD PTR DS:[B8E14C]                   ; |
00B75E08  |.  50                PUSH EAX                                        ; |Address => NULL
00B75E09  |.  E8 422489FF       CALL <JMP.&kernel32.VirtualFree>                ; \VirtualFree
00B75E0E  |.  8B45 CC             MOV EAX,DWORD PTR SS:[EBP-34]
00B75E11  |.  A3 4CE1B800       MOV DWORD PTR DS:[B8E14C],EAX
00B75E16  |.  33C0                XOR EAX,EAX
00B75E18  |.  8945 E8             MOV DWORD PTR SS:[EBP-18],EAX
00B75E1B  |>  8D45 FC             /LEA EAX,DWORD PTR SS:[EBP-4]
00B75E1E  |.  50                |PUSH EAX                                        ; /pOldProtect
00B75E1F  |.  8B45 E8             |MOV EAX,DWORD PTR SS:[EBP-18]                   ; |
00B75E22  |.  8D0480             |LEA EAX,DWORD PTR DS:[EAX+EAX*4]                ; |
00B75E25  |.  8B0485 205FB800    |MOV EAX,DWORD PTR DS:[EAX*4+B85F20]             ; |
00B75E2C  |.  50                |PUSH EAX                                        ; |NewProtect
00B75E2D  |.  8B45 E8             |MOV EAX,DWORD PTR SS:[EBP-18]                   ; |
00B75E30  |.  8D0480             |LEA EAX,DWORD PTR DS:[EAX+EAX*4]                ; |
00B75E33  |.  8B0485 145FB800    |MOV EAX,DWORD PTR DS:[EAX*4+B85F14]             ; |
00B75E3A  |.  50                |PUSH EAX                                        ; |Size
00B75E3B  |.  8B45 E8             |MOV EAX,DWORD PTR SS:[EBP-18]                   ; |
00B75E3E  |.  8D0480             |LEA EAX,DWORD PTR DS:[EAX+EAX*4]                ; |
00B75E41  |.  8B0485 105FB800    |MOV EAX,DWORD PTR DS:[EAX*4+B85F10]             ; |
00B75E48  |.  0305 4CE1B800       |ADD EAX,DWORD PTR DS:[B8E14C]                   ; |
00B75E4E  |.  50                |PUSH EAX                                        ; |Address
00B75E4F  |.  E8 042489FF       |CALL <JMP.&kernel32.VirtualProtect>             ; \VirtualProtect
00B75E54  |.  FF45 E8             |INC DWORD PTR SS:[EBP-18]
00B75E57  |.  8B45 E8             |MOV EAX,DWORD PTR SS:[EBP-18]
00B75E5A  |.  8D0480             |LEA EAX,DWORD PTR DS:[EAX+EAX*4]
00B75E5D  |.  833C85 105FB800 00 |CMP DWORD PTR DS:[EAX*4+B85F10],0
00B75E65  |.^ 75 B4             \JNZ SHORT Skype.00B75E1B
00B75E67  |.  A1 705FB800       MOV EAX,DWORD PTR DS:[B85F70]
00B75E6C  |.  0305 4CE1B800       ADD EAX,DWORD PTR DS:[B8E14C]
00B75E72  |.  6A 00             PUSH 0
00B75E74  |.  6A 01             PUSH 1
00B75E76  |.  FF35 4CE1B800       PUSH DWORD PTR DS:[B8E14C]
00B75E7C  |.  FFD0                CALL EAX
00B75E7E  |.  833D 4CE1B800 00    CMP DWORD PTR DS:[B8E14C],0
00B75E85  |.  75 05             JNZ SHORT Skype.00B75E8C
00B75E87  |.  E8 3805A7FF       CALL Skype.005E63C4
00B75E8C  |>  33C0                XOR EAX,EAX
00B75E8E  |.  5A                POP EDX
00B75E8F  |.  59                POP ECX
00B75E90  |.  59                POP ECX
00B75E91  |.  64:8910             MOV DWORD PTR FS:[EAX],EDX
00B75E94  |.  68 AE5EB700       PUSH Skype.00B75EAE
00B75E99  |>  8D45 A0             LEA EAX,DWORD PTR SS:[EBP-60]
00B75E9C  |.  BA 04000000       MOV EDX,4
00B75EA1  |.  E8 FEF188FF       CALL Skype.004050A4
00B75EA6  \.  C3                RETN
00B75EA7 .^ E9 2CEA88FF       JMP Skype.004048D8
00B75EAC .^ EB EB             JMP SHORT Skype.00B75E99
00B75EAE .  8BE5                MOV ESP,EBP
00B75EB0 .  5D                POP EBP
00B75EB1 .  C3                RETN

整个过程用C写大致是:

VirtualProtect(OEP, size, PAGE_EXECUTE_READWRITE, &oldProtect);
memset(OEP, 0, size);
VirtualProtect(OEP, size, PAGE_EXECUTE_READ, &oldProtect);

pMem = VirtualAlloc(NULL, 0x44C000, MEM_COMMIT, PAGE_READWRITE);
value = 0X????;
for(i=0;i<SegNum;i++){
for(j=0;j<Segs[i].size;j+=4) {
offset = ....
pMem[offset] = pOrig[offset] ^ value;
value += xxxx;
}
}

for(i=0;i<num;i++) {
if (info[i].flags == xxx)
Handle = LoadLibrary(info[i].name);
else {
pProc = GetProcAddress(Handle, info[i].name)
offset = info[i].offset;
pMem[offset] = pProc;
}

}
VirtualProtect(pStart, 0x44C000, PAGE_READ_WRITE, &oldProtect);
memcpy(pStart, pMem, 0x44C000);
VirtualFree(pMem, 0, MEM_RELEASE);
for(i=0;i<SegNum;i++){
offset = ...
VirtualProtect(pStart+offset, sizexx, NewProtectxxxx, &oldProtect);
}

看看它的作用:

a.) 解码的时候清掉了OEP处的一小段代码清, 可防止解码后的简单 DUMP

b.) 调用了 VirtualProtect, 对这段被解密的CODE 下的 memory write 断点不再起作用.

c.) 两份IAT, 第一份是标准的EXE的, 由 Loader 解析, 另一份由自己在解码后解析. 所以解码后, 即使内存中全是明文, DUMP 后, IAT 也不容易修复,

两份 IAT 在 memory 中相差很远, ImportRec 好象不行, 总不至于手工构造引入表(I T) 吧?

4. 程序中的 anti-debug 解除

用OllyDbg载入程序, 忽略所有 Exception, F9 能正确运行, 但是运行不久, 就出现

   Debugged program was unable to process exception

但是单独运行却是好好的, 十有八九是 SetUnhandledExceptionFilter 的 anti-debug.

Ctrl-F2 重新开始, bp SetUnhandledExceptionFilter, 然后 F9 运行, 运行不久就断下来, 果然不出所料.

Ctrl-G UnhandledExceptionFilter, 向下一点, 将CALL ZwQueryInformationProcess 下面的第二个条件跳转 NOP 掉,

// UnhandledExceptionFilter
7C59BCDC >  55                   PUSH EBP
7C59BCDD 8BEC                MOV EBP,ESP
7C59BCDF 6A FF                PUSH -1
7C59BCE1 68 C02E577C          PUSH kernel32.7C572EC0
...
7C59BD3B 6A 07                PUSH 7
7C59BD3D E8 7BBBFFFF          CALL kernel32.GetCurrentProcess
7C59BD42 50                   PUSH EAX
7C59BD43 FF15 B810577C       CALL DWORD PTR DS:[<&ntdll.NtQueryInformationProc>; ntdll.ZwQueryInformationProcess
7C59BD49 3BC3                CMP EAX,EBX
7C59BD4B 7C 09                JL SHORT kernel32.7C59BD56
7C59BD4D 395D C8             CMP DWORD PTR SS:[EBP-38],EBX
7C59BD50 0F85 49020000       JNZ kernel32.7C59BF9F ; // 这儿不能跳, NOP 掉就好了

这样, 程序总算开始听话. 由于Windows各个平台/版本的差异, 下载的 OLLYDBG 插件不起作用, 就只好手工改了.

4. 程序中的 anti-debug CODE 分析 (1)

解除 anti-debug 后总想看看, 这样的 anti-debug CODE 是怎么写的, 又是如何触发的.

bp SetUnhandledExceptionFilter, 可找到程序的 exception filter function 地址是 0072B670

分析一下这段CODE:

:0072B670 53                   push ebx

* Reference To: kernel32.GetCurrentThreadId, Ord:0111h
                              |
:0072B671 FF15909FA000          Call dword ptr [00A09F90]
:0072B677 3B05F017B200          cmp eax, dword ptr [00B217F0] ; ThreadId == [00B217F0]?
:0072B67D 741C                   je 0072B69B ; YES
:0072B67F A1EC17B200             mov eax, dword ptr [00B217EC]
:0072B684 33DB                   xor ebx, ebx
:0072B686 3BC3                   cmp eax, ebx
:0072B688 740B                   je 0072B695
:0072B68A 8B4C2408             mov ecx, dword ptr [esp+08]
:0072B68E 51                   push ecx
:0072B68F FFD0                   call eax
:0072B691 5B                   pop ebx
:0072B692 C20400                ret 0004

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B688(C)
|
:0072B695 33C0                   xor eax, eax
:0072B697 5B                   pop ebx
:0072B698 C20400                ret 0004

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B67D(C)
|
:0072B69B 8B0DE817B200          mov ecx, dword ptr [00B217E8] ; 一个 NUM
:0072B6A1 55                   push ebp
:0072B6A2 56                   push esi
:0072B6A3 8B742410             mov esi, dword ptr [esp+10] ; ExceptionInfo 参数
:0072B6A7 8D1449                lea edx, dword ptr [ecx+2*ecx]
:0072B6AA 57                   push edi
:0072B6AB 41                   inc ecx
:0072B6AC B801000000             mov eax, 00000001 ; 初始化返回值
:0072B6B1 8D3C952018B200       lea edi, dword ptr [4*edx+00B21820] ; 00B21820 处是一个表, 每项size=3*4
:0072B6B8 890DE817B200          mov dword ptr [00B217E8], ecx ; NUM 加 1 了,
:0072B6BE C74708FFFFFFFF       mov [edi+08], FFFFFFFF
:0072B6C5 8B0E                   mov ecx, dword ptr [esi] ; ExceptionRecord
:0072B6C7 8B29                   mov ebp, dword ptr [ecx] ; ExceptionCode
:0072B6C9 F7C500FFFF00          test ebp, 00FFFF00 ; 是 xx0000yy 的格式吗?
:0072B6CF 7516                   jne 0072B6E7
:0072B6D1 8BD5                   mov edx, ebp ; xx0000yy ==> xxyy
:0072B6D3 C1EA10                shr edx, 10
:0072B6D6 8ADA                   mov bl, dl
:0072B6D8 3219                   xor bl, byte ptr [ecx]
:0072B6DA 81E3FF000000          and ebx, 000000FF
:0072B6E0 33DA                   xor ebx, edx
:0072B6E2 66891F                mov word ptr [edi], bx ; 保存xxyy
:0072B6E5 EB05                   jmp 0072B6EC

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B6CF(C)
|
:0072B6E7 66C707FFFF             mov word ptr [edi], FFFF

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B6E5(U)
|
:0072B6EC 8B0E                   mov ecx, dword ptr [esi]
:0072B6EE 33DB                   xor ebx, ebx
:0072B6F0 8B510C                mov edx, dword ptr [ecx+0C]
:0072B6F3 895704                mov dword ptr [edi+04], edx ; 保存 ExceptionAddress
:0072B6F6 8B0E                   mov ecx, dword ptr [esi]
:0072B6F8 8B510C                mov edx, dword ptr [ecx+0C] ; edi = ExceptionAddress
:0072B6FB 33C9                   xor ecx, ecx
:0072B6FD 668B0F                mov cx, word ptr [edi]
:0072B700 81F91DC00000          cmp ecx, 0000C01D
:0072B706 0F8F4E020000          jg 0072B95A
:0072B70C 0F84C4010000          je 0072B8D6
:0072B712 81E903800000          sub ecx, 00008003
:0072B718 0F847D010000          je 0072B89B
:0072B71E 49                   dec ecx
:0072B71F 0F845E010000          je 0072B883
:0072B725 81E901400000          sub ecx, 00004001
:0072B72B 0F8534020000          jne 0072B965
:0072B731 803ACD                cmp byte ptr [edx], CD ; xxyy == C005 到这,
:0072B734 0F8578020000          jne 0072B9B2
:0072B73A 807A0101             cmp byte ptr [edx+01], 01
:0072B73E 0F856E020000          jne 0072B9B2
:0072B744 8B7A01                mov edi, dword ptr [edx+01]
:0072B747 32C9                   xor cl, cl
:0072B749 81FF01CC8DC0          cmp edi, C08DCC01
:0072B74F 7540                   jne 0072B791
:0072B751 8B5604                mov edx, dword ptr [esi+04] ; ExceptionAddress 处是 CD 01 CC 8D C0 到这
:0072B754 8B82B0000000          mov eax, dword ptr [edx+000000B0]
:0072B75A A3281BB200             mov dword ptr [00B21B28], eax ; [00B21B28] = context->eax
:0072B75F 8B4E04                mov ecx, dword ptr [esi+04]
:0072B762 8B91A8000000          mov edx, dword ptr [ecx+000000A8]
:0072B768 89152C1BB200          mov dword ptr [00B21B2C], edx ; [00B21B28] = context->eax
:0072B76E 8B4604                mov eax, dword ptr [esi+04]
:0072B771 8B88B8000000          mov ecx, dword ptr [eax+000000B8]
:0072B777 83C105                add ecx, 00000005
:0072B77A 8988B8000000          mov dword ptr [eax+000000B8], ecx ; context->eip += 5
:0072B780 A1681BB200             mov eax, dword ptr [00B21B68]
:0072B785 0C02                   or al, 02
:0072B787 A3681BB200             mov dword ptr [00B21B68], eax ; [00B21B68] |=2
:0072B78C 83C8FF                or eax, FFFFFFFF ; eax = -1
:0072B78F EB6E                   jmp 0072B7FF

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B74F(C)
|
:0072B791 81FF018DC0CC          cmp edi, CCC08D01
:0072B797 7568                   jne 0072B801
:0072B799 8B15681BB200          mov edx, dword ptr [00B21B68] ; ExceptionAddress 处是 CD 01 8D C0 CC 到这
:0072B79F 83CA04                or edx, 00000004
:0072B7A2 8915681BB200          mov dword ptr [00B21B68], edx ; [00B21B68] |=4
:0072B7A8 8B4604                mov eax, dword ptr [esi+04]
:0072B7AB F6C202                test dl, 02
:0072B7AE 8B80B0000000          mov eax, dword ptr [eax+000000B0]
:0072B7B4 A3201BB200             mov dword ptr [00B21B20], eax ; [00B21B20]  = context->eax
:0072B7B9 8B4E04                mov ecx, dword ptr [esi+04]
:0072B7BC 8B89A8000000          mov ecx, dword ptr [ecx+000000A8]
:0072B7C2 890D241BB200          mov dword ptr [00B21B24], ecx ; [00B21B20]  = context->edx
:0072B7C8 7428                   je 0072B7F2
:0072B7CA 8B2D281BB200          mov ebp, dword ptr [00B21B28]
:0072B7D0 8B152C1BB200          mov edx, dword ptr [00B21B2C]
:0072B7D6 2BC5                   sub eax, ebp
:0072B7D8 A3701BB200             mov dword ptr [00B21B70], eax ; [00B21B70]  = context->eax - [00B21B28]
:0072B7DD A1681BB200             mov eax, dword ptr [00B21B68]
:0072B7E2 1BCA                   sbb ecx, edx
:0072B7E4 80CC80                or ah, 80
:0072B7E7 890D741BB200          mov dword ptr [00B21B74], ecx ; [00B21B74]  = context->edx - [00B21B2C]
:0072B7ED A3681BB200             mov dword ptr [00B21B68], eax ; [00B21B68] |= 00008000

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B7C8(C)
|
:0072B7F2 8B4E04                mov ecx, dword ptr [esi+04]
:0072B7F5 83C8FF                or eax, FFFFFFFF
:0072B7F8 8381B800000004       add dword ptr [ecx+000000B8], 00000004 ; context->eip += 5

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B78F(U)
|
:0072B7FF B101                   mov cl, 01

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B797(C)
|
:0072B801 81E7FFFF0000          and edi, 0000FFFF
:0072B807 81FF01CF0000          cmp edi, 0000CF01
:0072B80D 7565                   jne 0072B874
:0072B80F 8B5604                mov edx, dword ptr [esi+04] ; ExceptionAddress 处是 CD 01 CF 到这
:0072B812 8B82C4000000          mov eax, dword ptr [edx+000000C4]
:0072B818 8B00                   mov eax, dword ptr [eax]
:0072B81A F6C408                test ah, 08
:0072B81D A36C1BB200             mov dword ptr [00B21B6C], eax
:0072B822 750A                   jne 0072B82E
:0072B824 810D681BB20000000100 or dword ptr [00B21B68], 00010000 ; [00B21B68] |= 00010000

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B822(C)
|
:0072B82E F6C401                test ah, 01
:0072B831 750A                   jne 0072B83D
:0072B833 810D681BB20000000200 or dword ptr [00B21B68], 00020000 ; [00B21B68] |= 00010000

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B831(C)
|
:0072B83D 8B5604                mov edx, dword ptr [esi+04]
:0072B840 B9E0B97200             mov ecx, 0072B9E0
:0072B845 41                   inc ecx
:0072B846 898AB8000000          mov dword ptr [edx+000000B8], ecx ; context->eip  = 0072B9E1
:0072B84C 8B4604                mov eax, dword ptr [esi+04]
:0072B84F 8B0D601BB200          mov ecx, dword ptr [00B21B60]
:0072B855 8988C4000000          mov dword ptr [eax+000000C4], ecx ; context->esp  = [00B21B60]
:0072B85B A1681BB200             mov eax, dword ptr [00B21B68]
:0072B860 0D00000400             or eax, 00040000
:0072B865 A3681BB200             mov dword ptr [00B21B68], eax ; [00B21B68] |= 00040000
:0072B86A E881FDFFFF             call 0072B5F0
:0072B86F E93B010000             jmp 0072B9AF

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B80D(C)
|
:0072B874 3ACB                   cmp cl, bl
:0072B876 0F8536010000          jne 0072B9B2
:0072B87C 33C0                   xor eax, eax
:0072B87E E92F010000             jmp 0072B9B2

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B71F(C)
|
:0072B883 391D641BB200          cmp dword ptr [00B21B64], ebx ; xxyy == 8004 到这
:0072B889 0F8520010000          jne 0072B9AF
:0072B88F A1681BB200             mov eax, dword ptr [00B21B68]
:0072B894 0C01                   or al, 01
:0072B896 E90F010000             jmp 0072B9AA

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B718(C)
|
:0072B89B 803ACC                cmp byte ptr [edx], CC ; xxyy == 8004 到这
:0072B89E 0F850E010000          jne 0072B9B2
:0072B8A4 807A018D             cmp byte ptr [edx+01], 8D
:0072B8A8 750F                   jne 0072B8B9
:0072B8AA 807A02C0             cmp byte ptr [edx+02], C0
:0072B8AE 7509                   jne 0072B8B9
:0072B8B0 A1681BB200             mov eax, dword ptr [00B21B68] ; ExceptionAddress 处是 CC 8D C0
:0072B8B5 0C08                   or al, 08 ; [00B21B68] |= 08
:0072B8B7 EB07                   jmp 0072B8C0

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072B8A8(C), :0072B8AE(C)
|
:0072B8B9 A1681BB200             mov eax, dword ptr [00B21B68]
:0072B8BE 0C10                   or al, 10 ; [00B21B68] |= 08

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B8B7(U)
|
:0072B8C0 A3681BB200             mov dword ptr [00B21B68], eax
:0072B8C5 8B4E04                mov ecx, dword ptr [esi+04]
:0072B8C8 83C8FF                or eax, FFFFFFFF
:0072B8CB FF81B8000000          inc dword ptr [ecx+000000B8] ; context->eip++
:0072B8D1 E9DC000000             jmp 0072B9B2

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B70C(C)
|
:0072B8D6 803A0F                cmp byte ptr [edx], 0F ; xxyy == C01D 到这
:0072B8D9 B902000000             mov ecx, 00000002 ; ecx = 2
:0072B8DE 7539                   jne 0072B919
:0072B8E0 807A010B             cmp byte ptr [edx+01], 0B
:0072B8E4 7533                   jne 0072B919
:0072B8E6 8B4604                mov eax, dword ptr [esi+04] ; ExceptionAddress 处是 0F 0B
:0072B8E9 8BA8B8000000          mov ebp, dword ptr [eax+000000B8]
:0072B8EF 03E9                   add ebp, ecx
:0072B8F1 89A8B8000000          mov dword ptr [eax+000000B8], ebp ; context->eip +=2
:0072B8F7 8B4604                mov eax, dword ptr [esi+04]
:0072B8FA 8BB8C0000000          mov edi, dword ptr [eax+000000C0]
:0072B900 81CF00090000          or edi, 00000900
:0072B906 89B8C0000000          mov dword ptr [eax+000000C0], edi ; context->EFlags |= 900 // OF, TF// 设置CPU单步 flags
:0072B90C 83C8FF                or eax, FFFFFFFF
:0072B90F C705641BB20001000000 mov dword ptr [00B21B64], 00000001

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072B8DE(C), :0072B8E4(C)
|
:0072B919 803A8D                cmp byte ptr [edx], 8D
:0072B91C 0F8590000000          jne 0072B9B2
:0072B922 807A01C0             cmp byte ptr [edx+01], C0
:0072B926 0F8586000000          jne 0072B9B2
:0072B92C 8B4604                mov eax, dword ptr [esi+04] ; ExceptionAddress 处是 8D C0
:0072B92F 8B90B8000000          mov edx, dword ptr [eax+000000B8]
:0072B935 03D1                   add edx, ecx
:0072B937 8990B8000000          mov dword ptr [eax+000000B8], edx ; context->eip +=2
:0072B93D 8B4604                mov eax, dword ptr [esi+04]
:0072B940 8B88C0000000          mov ecx, dword ptr [eax+000000C0]
:0072B946 80E5F6                and ch, F6
:0072B949 8988C0000000          mov dword ptr [eax+000000C0], ecx ; context->EFlags &= ~900 // 设置CPU单步 flags
:0072B94F 83C8FF                or eax, FFFFFFFF
:0072B952 891D641BB200          mov dword ptr [00B21B64], ebx
:0072B958 EB58                   jmp 0072B9B2

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B706(C)
|
:0072B95A 81E995C00000          sub ecx, 0000C095
:0072B960 7440                   je 0072B9A2
:0072B962 49                   dec ecx
:0072B963 7411                   je 0072B976

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B72B(C)
|
:0072B965 8B0D681BB200          mov ecx, dword ptr [00B21B68]
:0072B96B 80CD08                or ch, 08
:0072B96E 890D681BB200          mov dword ptr [00B21B68], ecx
:0072B974 EB3C                   jmp 0072B9B2

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B963(C)
|
:0072B976 803A0F                cmp byte ptr [edx], 0F ; xxyy == C096 到这
:0072B979 7537                   jne 0072B9B2
:0072B97B 807A0134             cmp byte ptr [edx+01], 34
:0072B97F 7531                   jne 0072B9B2
:0072B981 8B3D681BB200          mov edi, dword ptr [00B21B68] ; ExceptionAddress 处是 0F 34
:0072B987 83C8FF                or eax, FFFFFFFF
:0072B98A 81CF00100000          or edi, 00001000
:0072B990 893D681BB200          mov dword ptr [00B21B68], edi ; [00B21B68] |= 1000;
:0072B996 8B4E04                mov ecx, dword ptr [esi+04]
:0072B999 8381B800000002       add dword ptr [ecx+000000B8], 00000002 ; context->eip +=2
:0072B9A0 EB10                   jmp 0072B9B2

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B960(C)
|
:0072B9A2 A1681BB200             mov eax, dword ptr [00B21B68] ; xxyy == C095 到这
:0072B9A7 80CC04                or ah, 04

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072B896(U)
|
:0072B9AA A3681BB200             mov dword ptr [00B21B68], eax ; [00B21B68] |= 400;

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072B86F(U), :0072B889(C)
|
:0072B9AF 83C8FF                or eax, FFFFFFFF

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072B734(C), :0072B73E(C), :0072B876(C), :0072B87E(U), :0072B89E(C)
|:0072B8D1(U), :0072B91C(C), :0072B926(C), :0072B958(U), :0072B974(U)
|:0072B979(C), :0072B97F(C), :0072B9A0(U)
|
:0072B9B2 8B5604                mov edx, dword ptr [esi+04]
:0072B9B5 5F                   pop edi
:0072B9B6 895A10                mov dword ptr [edx+10], ebx ; context->dr3 = 0, 清除硬件断点
:0072B9B9 8B4E04                mov ecx, dword ptr [esi+04]
:0072B9BC 89590C                mov dword ptr [ecx+0C], ebx ; context->dr2 = 0
:0072B9BF 8B5604                mov edx, dword ptr [esi+04]
:0072B9C2 895A08                mov dword ptr [edx+08], ebx ; context->dr1 = 0
:0072B9C5 8B4E04                mov ecx, dword ptr [esi+04]
:0072B9C8 5E                   pop esi
:0072B9C9 5D                   pop ebp
:0072B9CA 895904                mov dword ptr [ecx+04], ebx ; context->dr0 = 0
:0072B9CD 5B                   pop ebx
:0072B9CE C20400                ret 0004

这段CODE 只是处理 Exception, 跟完了这段, 还是不太明白, 再想跟一跟 Exception 是如何触发的.

于是, 在 0072B9CE 处F8 返回到 kernel32.dll 领空后, 在 Memory Map 的 00401000 CODE 段上 F2 下断, 然后F9

断在0091885F

00918854 8B49 04             MOV ECX,DWORD PTR DS:[ECX+4]
00918857 50                   PUSH EAX
00918858 51                   PUSH ECX
00918859 FF15 ACA0A000       CALL DWORD PTR DS:[A0A0AC]          ; kernel32.WaitForSingleObject
0091885F 85C0                TEST EAX,EAX ; 返回到这儿了????????
00918861 74 12                JE SHORT Skype.00918875
00918863 33D2                XOR EDX,EDX
00918865 3D 02010000          CMP EAX,102
0091886A 0F94C2             SETE DL

前后看看, 感觉不应该是这样的. 刚开始也是一阵迷惑不解, 后来弄了好久才想可能是这样:

程序是多线程的, 有个线程由于在00918859 CALL kernel32.WaitForSingleObject 而进入kernel32 的领空等待,

而我所跟的线程在处理好 Exception 后, 回到 kernel32.dll 领空, 再F9, 却被等待的线程抢先返回到 CODE 段的

0091885F 而触发了在 0401000 CODE 段上的 F2 断点.

所以这条路走不通, 再想别的法子了.

5. 程序中的 anti-debug CODE 分析 (2)

根据 SetUnhandledExceptionFilter 找到下面的code:

* Referenced by a CALL at Address:
|:0072BF8C
|
:0072B9F0 53                   push ebx
:0072B9F1 56                   push esi
:0072B9F2 57                   push edi

* Reference To: kernel32.GetCurrentThreadId, Ord:0111h
                              |
:0072B9F3 FF15909FA000          Call dword ptr [00A09F90]
:0072B9F9 A3F017B200             mov dword ptr [00B217F0], eax ; ThreadID
:0072B9FE E83DF2FFFF             call 0072AC40 ; 将 SEH 链的最后一项填到第一项, 实际上是reset SEH 链
; 并返回第一项

* Reference To: kernel32.SetUnhandledExceptionFilter, Ord:02BFh
                              |
:0072BA03 8B3D949FA000          mov edi, dword ptr [00A09F94]
:0072BA09 6870B67200             push 0072B670
:0072BA0E 8BF0                   mov esi, eax ; 保存第一项
:0072BA10 FFD7                   call edi ; Call SetUnhandledExceptionFilter
:0072BA12 A3EC17B200             mov dword ptr [00B217EC], eax
:0072BA17 B904000000             mov ecx, 00000004

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BA54(C)
|
:0072BA1C A1381BB200             mov eax, dword ptr [00B21B38] ; rand的seed
:0072BA21 8B1D581BB200          mov ebx, dword ptr [00B21B58] ; VirtualAlloc 的一起始地址,  将用做 STACK
:0072BA27 8D1440                lea edx, dword ptr [eax+2*eax] ; 下面这几行就是　rand()
:0072BA2A 8D1490                lea edx, dword ptr [eax+4*edx]
:0072BA2D C1E204                shl edx, 04
:0072BA30 03D0                   add edx, eax
:0072BA32 C1E208                shl edx, 08
:0072BA35 2BD0                   sub edx, eax
:0072BA37 8D8490C39E2600       lea eax, dword ptr [eax+4*edx+00269EC3]
:0072BA3E 8B155C1BB200          mov edx, dword ptr [00B21B5C] ; VirtualAlloc 的 STACK size
:0072BA44 2BD1                   sub edx, ecx
:0072BA46 83C104                add ecx, 00000004
:0072BA49 A3381BB200             mov dword ptr [00B21B38], eax
:0072BA4E 83F920                cmp ecx, 00000020
:0072BA51 89041A                mov dword ptr [edx+ebx], eax ; 往memory的最后 0x20 bytes 填上一些随机数
:0072BA54 7EC6                   jle 0072BA1C ; 循环

:0072BA56 E8F5FBFFFF             call 0072B650 ; ******  这里就是去产生各种 Unhandled Exception 的地方 ******

:0072BA5B A1EC17B200             mov eax, dword ptr [00B217EC]
:0072BA60 50                   push eax
:0072BA61 FFD7                   call edi ; 重 Call SetUnhandledExceptionFilter, 进行恢复工作
:0072BA63 56                   push esi
:0072BA64 E8C7F1FFFF             call 0072AC30 ; 恢复正常的SEH 链
:0072BA69 A1E817B200             mov eax, dword ptr [00B217E8] ; 下面的 CODE 检查在程序的UnhandledExceptionFilter的运行结果是否正常
:0072BA6E 83C404                add esp, 00000004
:0072BA71 83F80B                cmp eax, 0000000B
:0072BA74 7544                   jne 0072BABA
:0072BA76 33D2                   xor edx, edx
:0072BA78 B92018B200             mov ecx, 00B21820
:0072BA7D B888A4A000             mov eax, 00A0A488

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BA9F(C)
|
:0072BA82 668B31                mov si, word ptr [ecx]
:0072BA85 663B30                cmp si, word ptr [eax]
:0072BA88 7517                   jne 0072BAA1
:0072BA8A 0FBF7002             movsx esi, word ptr [eax+02]
:0072BA8E 397108                cmp dword ptr [ecx+08], esi
:0072BA91 750E                   jne 0072BAA1
:0072BA93 83C004                add eax, 00000004
:0072BA96 42                   inc edx
:0072BA97 83C10C                add ecx, 0000000C
:0072BA9A 3DB4A4A000             cmp eax, 00A0A4B4
:0072BA9F 7CE1                   jl 0072BA82

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BA88(C), :0072BA91(C)
|
:0072BAA1 83FA0B                cmp edx, 0000000B ;  结果是否正常?
:0072BAA4 7514                   jne 0072BABA
:0072BAA6 8B0D681BB200          mov ecx, dword ptr [00B21B68]
:0072BAAC 81E116840400          and ecx, 00048416
:0072BAB2 81F916840400          cmp ecx, 00048416 ; flags 是 00048416 ?
:0072BAB8 740C                   je 0072BAC6

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BA74(C), :0072BAA4(C)
|
:0072BABA A1781BB200             mov eax, dword ptr [00B21B78] ; 非正常结果会到这,
:0072BABF 0C02                   or al, 02
:0072BAC1 A3781BB200             mov dword ptr [00B21B78], eax ; 设置 1 flag

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BAB8(C)
|
:0072BAC6 5F                   pop edi
:0072BAC7 5E                   pop esi
:0072BAC8 5B                   pop ebx
:0072BAC9 C3                   ret ; ret to 0072BF91

再跟一下返回后的CODE:

:0072BF8C E85FFAFFFF             call 0072B9F0

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BF8A(C)
|
:0072BF91 A1681BB200             mov eax, dword ptr [00B21B68] ; 返回到这
:0072BF96 F6C480                test ah, 80
:0072BF99 7419                   je 0072BFB4
:0072BF9B 392D741BB200          cmp dword ptr [00B21B74], ebp ; RDTSC 时间差的高 32bits
:0072BFA1 7C11                   jl 0072BFB4
:0072BFA3 7F0C                   jg 0072BFB1 ; 大于 0 就跳去  or edi, 1,
:0072BFA5 813D701BB20070640800 cmp dword ptr [00B21B70], 00086470 ; RDTSC 时间差的低 32bits < 00086470 ?
:0072BFAF 7203                   jb 0072BFB4

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BFA3(C)
|
:0072BFB1 83CF01                or edi, 00000001 ;

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BF99(C), :0072BFA1(C), :0072BFAF(C)
|
:0072BFB4 F605341BB20001       test byte ptr [00B21B34], 01
:0072BFBB 7547                   jne 0072C004

********** 去产生各种 Unhandled Exception  ****************

* Referenced by a CALL at Address:
|:0072BA56
|
:0072B650 9C                   pushfd ; 保存 Eflags
:0072B651 60                   pushad ; 保存 REGs
:0072B652 8925601BB200          mov dword ptr [00B21B60], esp ; 保存 esp
:0072B658 8B25581BB200          mov esp, dword ptr [00B21B58] ; ***** ESP 给改了, 从现在起, STACK 窗口没有有用的信息了 *******
:0072B65E 03255C1BB200          add esp, dword ptr [00B21B5C] ;
:0072B664 83EC20                sub esp, 00000020
:0072B667 61                   popad ; ***** 这儿可不对应上面的pushad, pop的全是随机数, 看0072BA51
:0072B668 FF25501BB200          jmp dword ptr [00B21B50] ; 到这, 除了eip, esp的值有用, 起它的6个 reg 中全是垃圾, 跳到...

跳到这, 每次运行可是跳到不同的地址!!!

下面这一小段 CODE 要产生 11 (0x0B) 个 Unhandled Exception, 完成不同的功能相当于CALL 0072B670 - 0072B9CE

********* 产生各种 Unhandled Exception 的 CODE *********
5F910152 /EB 02          JMP SHORT 5F910156 ; 跳
5F910154 C7             ???                                                 ; Unknown command
5F910155 FA             CLI
5F910156 /74 03          JE SHORT 5F91015B ; 跳
5F910158 |75 01          JNZ SHORT 5F91015B ; 跳
5F91015A 68 0F31CD01    PUSH 1CD310F

5F91015B 0F31          RDTSC ; 读 CPU 的xx counter, ==> EDX:EAX
5F91015D CD 01          INT 1 ; C0000005, eip+= 5
5F91015F CC             INT3
5F910160 8DC0          LEA EAX,EAX                                        ; Illegal use of register
5F910162 EB 02          JMP SHORT 5F910166 ; 跳
5F910164  - 0F84 0F31CD01 JE 615E3279

5F910166 0F31          RDTSC ; 再读 CPU 的xx counter, ==> EDX:EAX
5F910168 CD 01          INT 1 ; C0000005, eip+= 4
5F91016A 8DC0          LEA EAX,EAX                                        ; Illegal use of register
5F91016C CC             INT3 ; 80000003, eip++
5F91016D 0F0B          UD2 ; C000001D, eip+= 2, set OF,TP
; 80000004, from 77F9FF64
5F91016F CE             INTO ; C0000095, eip=eip
; 80000004, from 77F9FF64
5F910170 CC             INT3 ; 80000003, eip++
5F910171 9C             PUSHFD
5F910172 8DC0          LEA EAX,EAX                               ; 80000004, eip=eip
; C000001D, eip+=2, clear OF, TP
5F910174 CD 01          INT 1 ; C0000005, eip=0072B9E1

5F910176 CF             IRETD ; 这一句没执行

最后的 Exception 使 eip = 0072B9E1,esp=[00B21B60], 还有花指令

0072B9DD 90             NOP
0072B9DE 90             NOP
0072B9DF 90             NOP
0072B9E0 E8 619DC37E    CALL 7F365746

正确的应该是
0072B9E1 61             POPAD ; 这里才对应于 0072B651 的pushad
0072B9E2 9D             POPFD ;    对应于 0072B650 的pushfd
0072B9E3 C3             RETN

再看一下与上面 Unhandled Exception 相关的初始化部分:

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072A8E0(U)
|
:0072BBC0 83EC0C                sub esp, 0000000C
:0072BBC3 57                   push edi
:0072BBC4 8B3D781BB200          mov edi, dword ptr [00B21B78]
:0072BBCA 6A01                   push 00000001
:0072BBCC 68301BB200             push 00B21B30
:0072BBD1 897C2414             mov dword ptr [esp+14], edi

* Reference To: kernel32.InterlockedExchange, Ord:01D0h
                              |
:0072BBD5 FF15A49FA000          Call dword ptr [00A09FA4] ; 应该是读一 flag, 表示初始化或没有?
:0072BBDB 85C0                   test eax, eax
:0072BBDD 0F852F040000          jne 0072C012
:0072BBE3 8B15341BB200          mov edx, dword ptr [00B21B34]
:0072BBE9 A1381BB200             mov eax, dword ptr [00B21B38]
:0072BBEE 55                   push ebp
:0072BBEF 33ED                   xor ebp, ebp
:0072BBF1 42                   inc edx
:0072BBF2 3BC5                   cmp eax, ebp
:0072BBF4 56                   push esi
:0072BBF5 8915341BB200          mov dword ptr [00B21B34], edx
:0072BBFB 750B                   jne 0072BC08

* Reference To: kernel32.GetTickCount, Ord:018Bh
                              |
:0072BBFD FF15A09FA000          Call dword ptr [00A09FA0]
:0072BC03 A3381BB200             mov dword ptr [00B21B38], eax ; 初始化 rand 的 seed

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BBFB(C)
|
:0072BC08 833D2C60AD00FF       cmp dword ptr [00AD602C], FFFFFFFF
:0072BC0F 750F                   jne 0072BC20
:0072BC11 E8FAEFFFFF             call 0072AC10
:0072BC16 A32C60AD00             mov dword ptr [00AD602C], eax
:0072BC1B A1381BB200             mov eax, dword ptr [00B21B38]

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BC0F(C)
|
:0072BC20 392D401BB200          cmp dword ptr [00B21B40], ebp
:0072BC26 750A                   jne 0072BC32
:0072BC28 E823EFFFFF             call 0072AB50
:0072BC2D A1381BB200             mov eax, dword ptr [00B21B38]

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BC26(C)
|
:0072BC32 8A0D441BB200          mov cl, byte ptr [00B21B44]
:0072BC38 84C9                   test cl, cl
:0072BC3A 7517                   jne 0072BC53
:0072BC3C 68F817B200             push 00B217F8

* Reference To: kernel32.GetSystemInfo, Ord:0177h
                              |
:0072BC41 FF159C9FA000          Call dword ptr [00A09F9C] ; GetSystemInfo(), 下面用到
:0072BC47 A1381BB200             mov eax, dword ptr [00B21B38]
:0072BC4C C605441BB20001       mov byte ptr [00B21B44], 01

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BC3A(C)
|
:0072BC53 8A15341BB200          mov dl, byte ptr [00B21B34]
:0072BC59 F6C20E                test dl, 0E
:0072BC5C 7555                   jne 0072BCB3
:0072BC5E 8A0D441BB200          mov cl, byte ptr [00B21B44]
:0072BC64 84C9                   test cl, cl
:0072BC66 744B                   je 0072BCB3
:0072BC68 8B0D4C1BB200          mov ecx, dword ptr [00B21B4C]
:0072BC6E 3BCD                   cmp ecx, ebp
:0072BC70 7408                   je 0072BC7A
:0072BC72 392D581BB200          cmp dword ptr [00B21B58], ebp
:0072BC78 7539                   jne 0072BCB3

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BC70(C)
|
:0072BC7A 80E201                and dl, 01
:0072BC7D 8854240F             mov byte ptr [esp+0F], dl
:0072BC81 0F8471010000          je 0072BDF8
:0072BC87 3BCD                   cmp ecx, ebp
:0072BC89 7528                   jne 0072BCB3
:0072BC8B 68F817B200             push 00B217F8
:0072BC90 68481BB200             push 00B21B48
:0072BC95 6880000000             push 00000080
:0072BC9A C605451BB20000       mov byte ptr [00B21B45], 00
:0072BCA1 E82AFEFFFF             call 0072BAD0 ; 分配一段Memory,来放产生各种 Unhandled Exception 的 CODE,
起始地址 xxxx0000 中的 xxxx 是根据SystemInfo 随机生成, 每次运行都不一样, 而且一般都是 5xxx, 6xxx or 7xxxx,
跟系统 dll 中的地址混在一起, 在 OD 的 Memory Map 很容易被忽视掉. 刚开始的时候, 每次 exception 都在高地址空间,
我还总以为是哪个系统 dll 出问题了.

:0072BCA6 83C40C                add esp, 0000000C
:0072BCA9 A34C1BB200             mov dword ptr [00B21B4C], eax ; 保存地址

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BE22(C)
|
:0072BCAE A1381BB200             mov eax, dword ptr [00B21B38]

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BC5C(C), :0072BC66(C), :0072BC78(C), :0072BC89(C), :0072BDFE(C)
|:0072BE5F(U)
|
:0072BCB3 392D4C1BB200          cmp dword ptr [00B21B4C], ebp
:0072BCB9 0F84EA010000          je 0072BEA9
:0072BCBF 8A0D451BB200          mov cl, byte ptr [00B21B45]
:0072BCC5 84C9                   test cl, cl
:0072BCC7 0F85DC010000          jne 0072BEA9
:0072BCCD 8B15481BB200          mov edx, dword ptr [00B21B48]
:0072BCD3 33C9                   xor ecx, ecx
:0072BCD5 3BD5                   cmp edx, ebp
:0072BCD7 7637                   jbe 0072BD10

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BD0E(C)
|
:0072BCD9 8D1440                lea edx, dword ptr [eax+2*eax]
:0072BCDC 83C104                add ecx, 00000004
:0072BCDF 8D1490                lea edx, dword ptr [eax+4*edx]
:0072BCE2 C1E204                shl edx, 04
:0072BCE5 03D0                   add edx, eax
:0072BCE7 C1E208                shl edx, 08
:0072BCEA 2BD0                   sub edx, eax
:0072BCEC 8D8490C39E2600       lea eax, dword ptr [eax+4*edx+00269EC3]
:0072BCF3 8B154C1BB200          mov edx, dword ptr [00B21B4C]
:0072BCF9 A3381BB200             mov dword ptr [00B21B38], eax
:0072BCFE 89440AFC             mov dword ptr [edx+ecx-04], eax ; 将分配的 Memory 全填上随机数
:0072BD02 A1481BB200             mov eax, dword ptr [00B21B48]
:0072BD07 3BC8                   cmp ecx, eax
:0072BD09 A1381BB200             mov eax, dword ptr [00B21B38]
:0072BD0E 72C9                   jb 0072BCD9

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BCD7(C)
|
:0072BD10 392D2C60AD00          cmp dword ptr [00AD602C], ebp
:0072BD16 0F8586010000          jne 0072BEA2
:0072BD1C 8D0C40                lea ecx, dword ptr [eax+2*eax]
:0072BD1F 8B35B4A4A000          mov esi, dword ptr [00A0A4B4]
:0072BD25 53                   push ebx
:0072BD26 BF04000000             mov edi, 00000004
:0072BD2B 8D1488                lea edx, dword ptr [eax+4*ecx]
:0072BD2E 8B0D481BB200          mov ecx, dword ptr [00B21B48] ; 分配的 size
:0072BD34 C1E204                shl edx, 04
:0072BD37 03D0                   add edx, eax
:0072BD39 83C1BB                add ecx, FFFFFFBB ; size - 0x45
:0072BD3C C1E208                shl edx, 08
:0072BD3F 2BD0                   sub edx, eax
:0072BD41 8D8490C39E2600       lea eax, dword ptr [eax+4*edx+00269EC3]
:0072BD48 33D2                   xor edx, edx
:0072BD4A A3381BB200             mov dword ptr [00B21B38], eax ; 随机数
:0072BD4F F7F1                   div ecx ; rand() % (size - 0x45)
:0072BD51 A14C1BB200             mov eax, dword ptr [00B21B4C]
:0072BD56 8D4C0210             lea ecx, dword ptr [edx+eax+10] ; pStart + rand() % (size - 0x45) + 0x10
:0072BD5A 890D501BB200          mov dword ptr [00B21B50], ecx ; 代码起始地址pAddr, 随机的, 前面的 5F910152 就是这样来的

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BE97(C)
|
:0072BD60 B829000000             mov eax, 00000029 ; 下面一段解密一小段 CODE, 放到pAddr (也就是5F910152:-))
:0072BD65 2BC7                   sub eax, edi
:0072BD67 83F804                cmp eax, 00000004
:0072BD6A 0F87F4000000          ja 0072BE64
:0072BD70 0F83EE000000          jnb 0072BE64
:0072BD76 33DB                   xor ebx, ebx
:0072BD78 33D2                   xor edx, edx
:0072BD7A 3BC5                   cmp eax, ebp
:0072BD7C 762E                   jbe 0072BDAC
:0072BD7E 8D0CC5F8FFFFFF       lea ecx, dword ptr [8*eax+FFFFFFF8]
:0072BD85 894C2414             mov dword ptr [esp+14], ecx

...省略一些CODE

:0072BE91 83C704                add edi, 00000004
:0072BE94 83FF29                cmp edi, 00000029
:0072BE97 0F82C3FEFFFF          jb 0072BD60
:0072BE9D 8B7C2418             mov edi, dword ptr [esp+18]
:0072BEA1 5B                   pop ebx

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BD16(C)
|
:0072BEA2 C605451BB20001       mov byte ptr [00B21B45], 01 ; 解密结束

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BCB9(C), :0072BCC7(C)
|
:0072BEA9 A1341BB200             mov eax, dword ptr [00B21B34]
:0072BEAE 25FF010000             and eax, 000001FF
:0072BEB3 83F807                cmp eax, 00000007
:0072BEB6 751D                   jne 0072BED5
:0072BEB8 A0441BB200             mov al, byte ptr [00B21B44]
:0072BEBD 84C0                   test al, al
:0072BEBF 7414                   je 0072BED5
:0072BEC1 8B0D401BB200          mov ecx, dword ptr [00B21B40]
:0072BEC7 68F817B200             push 00B217F8
:0072BECC 51                   push ecx
:0072BECD E8BEF2FFFF             call 0072B190
:0072BED2 83C408                add esp, 00000008

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BEB6(C), :0072BEBF(C)
|
:0072BED5 8B15341BB200          mov edx, dword ptr [00B21B34]
:0072BEDB 81E2FF010000          and edx, 000001FF
:0072BEE1 81FA03010000          cmp edx, 00000103
:0072BEE7 7549                   jne 0072BF32
:0072BEE9 F605781BB20004       test byte ptr [00B21B78], 04
:0072BEF0 7540                   jne 0072BF32
:0072BEF2 892D681BB200          mov dword ptr [00B21B68], ebp
:0072BEF8 E863EEFFFF             call 0072AD60
:0072BEFD 392D2C60AD00          cmp dword ptr [00AD602C], ebp
:0072BF03 7510                   jne 0072BF15
:0072BF05 A1401BB200             mov eax, dword ptr [00B21B40]
:0072BF0A 50                   push eax
:0072BF0B E850F0FFFF             call 0072AF60
:0072BF10 83C404                add esp, 00000004
:0072BF13 EB05                   jmp 0072BF1A

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BF03(C)
|
:0072BF15 E8A6F3FFFF             call 0072B2C0

* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0072BF13(U)
|
:0072BF1A F705681BB200E0030000 test dword ptr [00B21B68], 000003E0
:0072BF24 740C                   je 0072BF32
:0072BF26 A1781BB200             mov eax, dword ptr [00B21B78]
:0072BF2B 0C04                   or al, 04
:0072BF2D A3781BB200             mov dword ptr [00B21B78], eax

* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:0072BEE7(C), :0072BEF0(C), :0072BF24(C)
|
:0072BF32 A1341BB200             mov eax, dword ptr [00B21B34]
:0072BF37 B911000000             mov ecx, 00000011
:0072BF3C 99                   cdq
:0072BF3D F7F9                   idiv ecx
:0072BF3F 85D2                   test edx, edx
:0072BF41 0F85BD000000          jne 0072C004
:0072BF47 392D4C1BB200          cmp dword ptr [00B21B4C], ebp
:0072BF4D 0F84B1000000          je 0072C004
:0072BF53 392D581BB200          cmp dword ptr [00B21B58], ebp
:0072BF59 0F84A5000000          je 0072C004
:0072BF5F A12C60AD00             mov eax, dword ptr [00AD602C]
:0072BF64 892D701BB200          mov dword ptr [00B21B70], ebp
:0072BF6A 3BC5                   cmp eax, ebp
:0072BF6C 892D741BB200          mov dword ptr [00B21B74], ebp
:0072BF72 892D681BB200          mov dword ptr [00B21B68], ebp
:0072BF78 892D6C1BB200          mov dword ptr [00B21B6C], ebp
:0072BF7E 892DE817B200          mov dword ptr [00B217E8], ebp
:0072BF84 892D641BB200          mov dword ptr [00B21B64], ebp
:0072BF8A 7505                   jne 0072BF91
:0072BF8C E85FFAFFFF             call 0072B9F0 ; 这儿开始干坏事, 前面已经分析过了.

没了, 好累!!!

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[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)

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南蛮妈妈雪币： 233 活跃值： (130) 能力值： ( LV8，RANK：130 ) 在线值：发帖 6 回帖 472 粉丝 0 关注私信	南蛮妈妈 3 2 楼这样的文章都是要收藏了感谢LZ 2006-2-17 09:17 0
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