190 lines
12 KiB
Markdown
190 lines
12 KiB
Markdown
任务是找到某串神秘的字符串内容 `Willbeharder`
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上来有个奇怪的函数，跳过不管
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```assembly
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00401255 | 55 | push ebp | EP
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00401256 | 8BEC | mov ebp,esp |
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00401258 | 51 | push ecx | ecx:EntryPoint
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00401259 | 6A 10 | push 10 | secret? ↓
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0040125B | 68 C8504000 | push bugger.4050C8 | 4050C8:"jdy28lambcoplwerewaf23sdfcvxc"
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00401260 | 68 F0504000 | push bugger.4050F0 |
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00401265 | E8 BEFEFFFF | call bugger.401128 |
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0040126A | 33DB | xor ebx,ebx |
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0040126C | 64:8B73 18 | mov esi,dword ptr fs:[ebx+18] | esi:EntryPoint
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00401270 | 8B7E 30 | mov edi,dword ptr ds:[esi+30] | edi:EntryPoint
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```
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这里获取系统版本号信息，不过并没有什么用（至少没有给我带进`ExitProcessImplementation`
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```assembly
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00401273 | E8 B2010000 | call <JMP.&_GetVersionStub@0> |
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00401278 | 33D2 | xor edx,edx |
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0040127A | 3D 00000080 | cmp eax,80000000 |
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0040127F | 73 05 | jae bugger.401286 |
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00401281 | 8A57 02 | mov dl,byte ptr ds:[edi+2] |
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00401284 | EB 0E | jmp bugger.401294 |
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00401286 | 0B56 20 | or edx,dword ptr ds:[esi+20] |
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00401289 | 8B4F 20 | mov ecx,dword ptr ds:[edi+20] |
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0040128C | 0B57 54 | or edx,dword ptr ds:[edi+54] |
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0040128F | 83E1 01 | and ecx,1 |
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00401292 | 0BD1 | or edx,ecx |
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00401294 | 0BD2 | or edx,edx |
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00401296 | 75 07 | jne bugger.40129F |
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00401298 | 6A 00 | push 0 |
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0040129A | E8 85010000 | call <JMP.&_ExitProcessImplementation@4> |
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```
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之后是检测OD，如果没检测到窗体名为OLLYDBG的就退出
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```assembly
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0040129F | 6A 00 | push 0 |
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004012A1 | 68 4661C479 | push 79C46146 |
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004012A6 | 68 CDE9540C | push C54E9CD |
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004012AB | 68 7971D6CC | push CCD67179 |
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004012B0 | 68 A453F425 | push 25F453A4 |
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004012B5 | 54 | push esp |
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004012B6 | 68 F0504000 | push bugger.4050F0 |
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004012BB | E8 D5FDFFFF | call bugger.401095 |
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004012C0 | 8BCC | mov ecx,esp | ecx:_GetVersion_Win8@0
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004012C2 | 6A 00 | push 0 |
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004012C4 | 51 | push ecx | ecx:"OLLYDBG"
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004012C5 | E8 3C010000 | call <JMP.&_FindWindowA@8> |
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004012CA | 83F8 00 | cmp eax,0 | Detect OD
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004012CD | 0BC0 | or eax,eax |
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004012CF | 74 07 | je bugger.4012D8 |
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004012D1 | E8 0E000000 | call bugger.4012E4 |
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004012D6 | EB 07 | jmp bugger.4012DF |
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004012D8 | 6A 00 | push 0 | ? 你什么意思
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004012DA | E8 45010000 | call <JMP.&_ExitProcessImplementation@4> |
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004012DF | 59 | pop ecx | ecx:_GetVersion_Win8@0
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```
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之后来到一个新的函数 `4012E4`，这里准备检查od进程&再查一遍od窗体
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```
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004012E4 | 55 | push ebp |
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004012E5 | 8BEC | mov ebp,esp |
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004012E7 | 51 | push ecx |
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004012E8 | B8 28010000 | mov eax,128 |
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004012ED | A3 50524000 | mov dword ptr ds:[405250],eax |
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004012F2 | 6A 00 | push 0 |
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004012F4 | 6A 02 | push 2 |
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004012F6 | E8 23010000 | call <JMP.&_CreateToolhelp32Snapshot@8> |
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004012FB | A3 78534000 | mov dword ptr ds:[405378],eax |
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00401300 | 68 50524000 | push bugger.405250 |
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00401305 | 50 | push eax |
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00401306 | E8 2B010000 | call <JMP.&_Process32First@8> |
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0040130B | 6A 00 | push 0 |
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0040130D | 68 4661C479 | push 79C46146 |
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00401312 | 68 CDE9540C | push C54E9CD |
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00401317 | 68 7971D6CC | push CCD67179 |
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0040131C | 68 A453F425 | push 25F453A4 |
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00401321 | 54 | push esp |
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00401322 | 68 F0504000 | push bugger.4050F0 |
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00401327 | E8 69FDFFFF | call bugger.401095 |
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0040132C | 8BCC | mov ecx,esp | esp: "OLLYDBG"
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0040132E | 6A 00 | push 0 |
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00401330 | 51 | push ecx |
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00401331 | E8 D0000000 | call <JMP.&_FindWindowA@8> |
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00401336 | 83F8 00 | cmp eax,0 |
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00401339 | 0BC0 | or eax,eax |
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0040133B | 74 07 | je bugger.401344 |
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0040133D | E8 0C000000 | call bugger.40134E |
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00401342 | EB 05 | jmp bugger.401349 |
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00401344 | E8 6A000000 | call bugger.4013B3 |
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00401349 | 59 | pop ecx |
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0040134A | C9 | leave |
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0040134B | C2 0400 | ret 4 |
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```
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如果找不到了就进 `4013B3`，找到了就进 `40134E`
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先看`40134E`，遍历当前进程查找`OLLYDBG.EXE`，找到就掐然后退出自身
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```assembly
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0040134E | 55 | push ebp |
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0040134F | 8BEC | mov ebp,esp |
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00401351 | 51 | push ecx |
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00401352 | 6A 00 | push 0 |
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00401354 | 68 45584500 | push 455845 |
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00401359 | 68 4442472E | push 2E474244 |
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0040135E | 68 4F4C4C59 | push 594C4C4F |
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00401363 | 8BCC | mov ecx,esp |
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00401365 | 51 | push ecx | ecx:"OLLYDBG.EXE"
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00401366 | 68 74524000 | push bugger.405274 | 405274:"[System Process]"
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0040136B | E8 D8000000 | call <JMP.&_lstrcmpStub@8> |
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00401370 | 0BC0 | or eax,eax |
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00401372 | 75 2D | jne bugger.4013A1 |
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00401374 | FF35 58524000 | push dword ptr ds:[405258] |
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0040137A | 6A 01 | push 1 |
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0040137C | 68 FF0F1F00 | push 1F0FFF |
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00401381 | E8 AA000000 | call <JMP.&_OpenProcessStub@12> |
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00401386 | A3 80534000 | mov dword ptr ds:[405380],eax |
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0040138B | 6A 00 | push 0 |
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0040138D | FF35 80534000 | push dword ptr ds:[405380] |
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00401393 | E8 AA000000 | call <JMP.&_TerminateProcessStub@8> |
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00401398 | 6A 00 | push 0 |
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0040139A | E8 85000000 | call <JMP.&_ExitProcessImplementation@4> |
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0040139F | EB 10 | jmp bugger.4013B1 |
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004013A1 | 68 50524000 | push bugger.405250 |
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004013A6 | FF35 78534000 | push dword ptr ds:[405378] |
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004013AC | E8 8B000000 | call <JMP.&_Process32Next@8> |
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004013B1 | EB 9B | jmp bugger.40134E |
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```
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再看下`4013B3`，再查一遍od窗体名，如果没找到就把密文`Willbeharder`交出来，否则退出进程
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```assembly
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004013B3 | 55 | push ebp |
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004013B4 | 8BEC | mov ebp,esp |
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004013B6 | 51 | push ecx |
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004013B7 | 6A 00 | push 0 |
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004013B9 | 68 4661C479 | push 79C46146 |
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004013BE | 68 CDE9540C | push C54E9CD |
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004013C3 | 68 7971D6CC | push CCD67179 |
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004013C8 | 68 A453F425 | push 25F453A4 |
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004013CD | 54 | push esp |
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004013CE | 68 F0504000 | push bugger.4050F0 |
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004013D3 | E8 BDFCFFFF | call bugger.401095 |
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004013D8 | 8BCC | mov ecx,esp |
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004013DA | 6A 00 | push 0 |
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004013DC | 51 | push ecx |
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004013DD | E8 24000000 | call <JMP.&_FindWindowA@8> |
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004013E2 | 83F8 00 | cmp eax,0 |
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004013E5 | 0BC0 | or eax,eax |
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004013E7 | 74 09 | je bugger.4013F2 |
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004013E9 | 6A 00 | push 0 |
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004013EB | E8 34000000 | call <JMP.&_ExitProcessImplementation@4> |
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004013F0 | EB 0F | jmp bugger.401401 |
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004013F2 | 68 B7504000 | push bugger.4050B7 | 4050B7:"Willbeharder"
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004013F7 | 68 F0504000 | push bugger.4050F0 |
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004013FC | E8 94FCFFFF | call bugger.401095 |
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00401401 | 59 | pop ecx |
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00401402 | C9 | leave |
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00401403 | C2 0400 | ret 4 |
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```
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要Patch的话
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```assembly
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1.
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004012CF | 74 07 | je bugger.4012D8 |
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NOP掉
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2.
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0040133B | 74 07 | je bugger.401344 |
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↓ Patch
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0040133B | EB 07 | jmp bugger.401344 |
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3.
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004013E7 | 74 09 | je bugger.4013F2 |
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↓ Patch
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004013E7 | EB 09 | jmp bugger_patched.4013F2 |
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```
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可在`00401401`处设置断点
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