OD附加功能分析

时间:2022-04-28 16:47:14

OD版本:OllyICE v1.10

 

在从文件菜单选择附加后,OD会在注册一个窗口类后,先创建一个0x138大小的进程表; 再是CreateWindowExA 创建窗口;

 

00478013 loc_478013:                            

00478013                 push    0               ; int

00478015                 push    offset sub_477C10 ; int

0047801A                 push    100h            ; int

0047801F                 push    310h            ; int

00478024                 push    offset asc_4C20E8 ; "?

00478029                 push    offset byte_4ED3FC ; dest

0047802E                 call    _Createsorteddata     //此处为创建进程表

 

表的结构体如下:

table           struc ; (sizeof=0x138)

name            db 260 dup(?)   //表的名字

count       dd ?                //表中保存的数据个数

maxcount        dd ?           //表能保存的最大数量

currentobj      dd ?            //当前选中的表中数据的ID,未选中时为为-1

addrcurobj       dd ?             //当前选中数据的地址,未选中时为0

size            dd ?            //表中每个数据的大小

field_118       dd ?

baseaddrobj           dd ?      //表中保存的数据的基地址

fncmp              dd ?        //函数首地址

field_124       dd ?

field_128      dd ?    

sign            dd ?   //标志位,表示是否有索引数据(也就是baseaddroffset是否有效)

baseaddroffset        dd ?       //索引数据,标示每个数据在表中的顺序

field_134       dd ?

table           ends

 

 

然后OD会获取自己的进程ID号,并获取EnumProcesses ,EnumProcessModules,GetModuleFileNameExA 三个函数的地址;

 

 

00475138 loc_475138:                            

00475138                 xor     ebx, ebx

0047513A                 call    GetCurrentProcessId  //获取OD本身的进程ID

0047513F                 mov     [ebp+var_10], eax

00475142                 mov     eax, dword_4D5A0C

00475147                 test    eax, eax

00475149                 jz      loc_4752AF

0047514F                 push    offset aEnumprocesses ; "EnumProcesses"

00475154                 push    eax             ; hModule

00475155                 call    GetProcAddress//获取EnumProcesses地址

0047515A                 mov     edi, eax

0047515C                 push    offset aEnumprocessm_0 ; "EnumProcessModules"

00475161                 mov     eax, dword_4D5A0C

00475166                 push    eax             ; hModule

00475167                 call    GetProcAddress//获取EnumProcessModules的地址

0047516C                 mov     [ebp+var_20], eax

0047516F                 push    offset aGetmodulefil_0 ; "GetModuleFileNameExA"

00475174                 mov     edx, dword_4D5A0C

0047517A                 push    edx             ; hModule

0047517B                 call    GetProcAddress//获取GetModuleFileNameExA地址

00475180                 mov     [ebp+var_24], eax

 

 

之后OD枚举系统中的所有进程并保存枚举到的进程;

 

004751A3                 push    eax

004751A4                 push    400h

004751A9                 push    edx

004751AA                 call    edi   // EnumProcesses  枚举进程

004751AC                 test    eax, eax

004751AE                 jnz     short loc_4751B3

 

 

接着再一个循环中OD会尝试利用OpenProcess打开枚举到的所有进程,如果进程ID不等于OD本身ID 并且OpenProcess函数返回成功的话,OD会利用EnumProcessModules枚举模块并获取第一个模块句柄,如果EnumProcessModules返回成功,OD会利用GetModuleFileNameExA获取模块全路径,最后把进程ID和 模块全路径 按顺序保存到上面建立的 进程表 中; 

 

004751DB loc_4751DB:                             

004751DB                 mov     eax, [edi]

004751DD                 cmp     eax, [ebp+var_10]// 判断是否等于OD本身ID

004751E0                 jz      loc_47529B

004751E6                 push    eax             ; dwProcessId

004751E7                 push    0               ; bInheritHandle

004751E9                 push    410h            ; dwDesiredAccess

004751EE                 call    OpenProcess

004751F3                 mov     [ebp+hObject], eax

004751F6                 cmp     [ebp+hObject], 0//判断进程是否打开成功

004751FA                 jz      loc_47529B

00475200                 lea     edx, [ebp+var_C]

00475203                 lea     ecx, [ebp+var_1C]

00475206                 push    edx

00475207                 push    4

00475209                 push    ecx

0047520A                 mov     eax, [ebp+hObject]

0047520D                 push    eax

0047520E                 call    [ebp+var_20] //EnumProcessModules枚举进程模块

00475211                 test    eax, eax

00475213                 jnz     short loc_475220

00475215                 mov     edx, [ebp+hObject]

00475218                 push    edx             ; hObject

00475219                 call    CloseHandle//如果EnumProcessModules不成功则关闭句柄

0047521E                 jmp     short loc_47529B

 

 

如果EnumProcessModules成功则走如下分支

 

00475220 loc_475220:                          

00475220                 mov     ecx, [edi]      ; int

00475222                 xor     eax, eax        ; int

00475224                 mov     dword ptr [ebp+arglist], ecx//把进程ID保存到一临时结构体中

0047522A                 lea     edx, [ebp+var_528]

00475230                 mov     [ebp+var_730], 1

0047523A                 mov     [ebp+var_72C], eax

00475240                 mov     [ebp+var_528], 0

00475247                 push    104h

0047524C                 push    edx

0047524D                 mov     ecx, [ebp+var_1C]

00475250                 push    ecx

00475251                 mov     eax, [ebp+hObject]

00475254                 push    eax

00475255                 call    [ebp+var_24]//GetModuleFileNameExA获得模块路径

00475258                 mov     [ebp+var_425], 0

0047525F                 mov     edx, [ebp+hObject]

00475262                 push    edx             ; hObject

00475263                 call    CloseHandle//关闭打开的进程句柄

00475268                 push    0

0047526A                 lea     ecx, [ebp+var_728]

00475270                 push    ecx

00475271                 push    0

00475273                 push    0

00475275                 lea     eax, [ebp+var_528]

0047527B                 push    eax

0047527C                 call    004A51BC   //把模块路径复制到临时变量结构体中

00475281                 add     esp, 14h

00475284                 lea     edx, [ebp+arglist] ; int

0047528A                 mov     [ebp+var_628], 0

00475291                 push    edx             ; arglist

00475292                 push    esi             ; src

00475293                 call    _Addsorteddata //把包含了进程ID与模块路径的临时结构体添加到进程表中

00475298                 add     esp, 8

 

0047529B loc_47529B:                                                               

0047529B                 inc     [ebp+var_4]

0047529E                 add     edi, 4

004752A1                 mov     ecx, [ebp+var_4]

004752A4                 cmp     ecx, [ebp+var_8] //检查比较次数是否小于枚举到的进程个数

004752A7                 jl      loc_4751DB //小于则继续循环

 

           

 

枚举完进程后接着检查进程表中保存的数据是否小于等于0;如果小于等于则直接返回;

反之则EnumWindows,并利用GetWindowText函数获取桌面窗口的标题

保存到 进程表中 对应的进程数据中

004753E9              cmp     dword ptr [esi+104h], 0//比较进程表中数据是否小于0

004753F0              jle     short loc_4753FD

004753F2              push    esi       //此处的参数是 进程表的首地址

004753F3              push    offset sub_477A90 ; lpEnumFunc

004753F8              call    EnumWindows

 

 

 

以下是EnumWindowsProc的功能

00477AA8                 lea     edx, [ebp+dwProcessId]

00477AAB                 push    edx             ; lpdwProcessId

00477AAC                 mov     ecx, [ebp+hWnd]

00477AAF                 push    ecx        //枚举的窗口进程的句柄

00477AB0                 call    GetWindowThreadProcessId //获得窗口的进程ID

 

 

下面是个循环 利用上面得到的进程ID与进程表中保存的进程ID做比较,如果相等 则GetWindowTextA获得窗口标题,并把得到的数据保存在进程表中对应的位置

00477ABB loc_477ABB:                             ; CODE XREF: sub_477A90+75j

00477ABB                 mov     edx, [ebx]

00477ABD                 cmp     edx, [ebp+dwProcessId]

00477AC0                 jnz     short loc_477AF8

00477AC2                 cmp     byte ptr [ebx+10Ch], 0

00477AC9                 jnz     short loc_477AF8

00477ACB                 push    100h            ; nMaxCount

00477AD0                 mov     ecx, eax

00477AD2                 lea     eax, [ecx+eax*2]

00477AD5                 shl     eax, 4

00477AD8                 add     eax, ecx

00477ADA                 shl     eax, 4

00477ADD                 add     esi, eax

00477ADF                 add     esi, 10Ch

00477AE5                 push    esi  //此buffer既为进程表中不同进程对应的数据地址

00477AE6                 mov     eax, [ebp+hWnd]

00477AE9                 push    eax             ; hWnd

00477AEA                 call    GetWindowTextA  //获得枚举的窗口的标题并保存到进程表中对应的进程数据中

 

00477AEF                 mov     byte ptr [ebx+20Bh], 0

00477AF6                 jmp     short loc_477B07获得后跳出循环 利用枚举到的下一个窗口再次执行此函数

 

 

如果进程ID不相等则继续循环

00477AF8                 inc     eax

00477AF9                 add     ebx, 310h  0x310为结构体大小

00477AFF loc_477AFF:                           

00477AFF                 cmp     eax, [edi+104h] //检查比较的次数 是否大于进程表中 的进程数

00477B05                 jl      short loc_477ABB

 

在EnumWindows函数执行完成返回后,OD会调用InvalidateRect函数,使显示进程的窗口重绘;

004782F8                 push    0               ; bErase

004782FA                 push    0               ; lpRect

004782FC                 mov     edx, dword_4ED3F8

00478302                 push    edx             ; hWnd

00478303                 call    InvalidateRect

 

 

OD会对进程表中的 ID号,把相对应的索引数据进行从小到大的排序..

004AC501                 jz      short loc_4AC51C

004AC503                 mov     edx, [ebp+fcmp]

004AC506                 mov     ecx, [ebp+nelem]

004AC509                 push    ecx //第一个参数为进程表中的数据个数

004AC50A                 mov     dword_50A5F8, edx

004AC510                 mov     eax, [ebp+base] //第二个参数为进程表中索引数据的首地址

004AC513                 push    eax

004AC514                 call    sub_4AC310

最终函数会调用到进程表结构体中偏移0x120位置保存的函数地址;

 

 

当从进程窗口列表框中选择要附加的进程并点击附加按钮后,OD会记录其序号,并通过序号计算出此进程在 进程表中的 偏移位置,通过偏移位置得到进程ID

 

004784A5                 mov     eax, dword_4ED508//得到要附加进程在列表框中的位置

004784AA                 test    eax, eax

004784AC                 jl      loc_47867B//如果进程号小于0则直接返回;

004784B2                 cmp     eax, dword_4ED500/比较序号是否大于进程总数

004784B8                 jge     loc_47867B  //大于也直接返回

004784BE                 mov     edx, dword_4ED52C

004784C4                 mov     esi, [edx+eax*4]

004784C7                 imul    esi, dword_4ED510

004784CE                 add     esi, dword_4ED518 //上面几步是计算得出附加的进程在进程表中存储的首地址

004784D4                 mov     eax, [esi]  //得到进程ID

004784D6                 cmp     eax, dword_4D5A70 //判断OD是否正在调试此程序

004784DC                 jnz     short loc_4784F4

 

 

如果此时OD正在调试此程序则会弹出一错误框提示 进程“xxxx”是你正在调试的程序……

并直接返回。

 

004784DE                 add     esi, 0Ch

004784E1                 push    esi             ; arglist

004784E2                 push    offset asc_4C2122 ; "?

004784E7                 call    _Error

004784EC                 add     esp, 8

004784EF                 jmp     loc_47867B//直接返回..

 

 

接着OD会申请一定的空间并初始化一些表,如:dll句柄表,线程表,统计表,等等…

 

004784F4 loc_4784F4:                           

004784F4                 push    1

004784F6                 call    sub_4758A4

004784FB                 pop     ecx

004784FC                 test    eax, eax

004784FE                 jnz     loc_47867B

00478504                 call    sub_47540C //此函数用于申请空间并初始化表

00478509                 test    eax, eax //判断是否初始化成功。

0047850B                 jz      short loc_47851D

0047850D                 push    offset aIFUC    ; "无法分配足够内存"

00478512                 call    _Error//如果不成功则会报告内存内存不足…并直接返回

00478517                 pop     ecx

00478518                 jmp     loc_47867B

 

 

在0046b258这个函数中OD会根据用户设置的导入库保存在ollydbg.ini文件中的[Import libraries]项解析调试程序中的库函数;

下面就是处理的一个循环过程

 

0046B268 loc_46B268:                          

0046B268                 push    ebx

0046B269                 lea     eax, [edi+4F8h]

0046B26F                 push    eax             ; format

0046B270                 lea     edx, [esp+318h+buffer]

0046B277                 push    edx             ; buffer

0046B278                 call    _sprintf

0046B27D                 add     esp, 0Ch

0046B280                 push    offset FileName ; lpFileName

0046B285                 push    104h            ; nSize

0046B28A                 lea     ecx, [esp+318h+path]

0046B28E                 push    ecx             ; lpReturnedString

0046B28F                 lea     eax, [edi+4]

0046B292                 push    eax             ; lpDefault

0046B293                 lea     edx, [esp+320h+buffer]

0046B29A                 push    edx             ; lpKeyName

0046B29B                 lea     ecx, [edi+503h]

0046B2A1                 push    ecx             ; lpAppName

0046B2A2                 call    GetPrivateProfileStringA  //得到ollydbg.ini 文件中[Import libraries]项中的路径

0046B2A7                 cmp     [esp+310h+path], 0

0046B2AB                 jz      short loc_46B2E6

0046B2AD                 mov     eax, hCursor

0046B2B2                 push    eax             ; hCursor

0046B2B3                 call    SetCursor

0046B2B8                 mov     esi, eax

0046B2BA                 xor     eax, eax

0046B2BC                 mov     dword_4EAE50, eax

0046B2C1                 push    0               ; int

0046B2C3                 lea     edx, [esp+314h+arglist]

0046B2CA                 push    edx             ; arglist

0046B2CB                 lea     ecx, [esp+318h+path]

0046B2CF                 push    ecx             ; path

0046B2D0                 call    sub_469818//此函数里面主要是负责解析的函数

0046B2D5                 add     esp, 0Ch

0046B2D8                 call    sub_46718C

0046B2DD                 cmp     dword_4EAE50, 0

0046B2E4                 jnz     short loc_46B2F3

0046B2E6

0046B2E6 loc_46B2E6:     

0046B2E6                 inc     ebx

0046B2E7                 cmp     ebx, 0C8h

0046B2ED                 jl      loc_46B268

 

 

 

等做完上面的工作后,OD才开始真正的附加 主要是通过DebugActiveProcess对程序附加

00478522                 mov     eax, [esi]

00478524                 push    eax             /要附加的进程ID

00478525                 call    DebugActiveProcess

0047852A                 test    eax, eax

 

之后OD按一定格式设置窗口标题;

004785A5                 push    edx

004785A6                 push    offset byte_4D5A7C

004785AB                 push    offset aOllyice ; "OllyICE"

004785B0                 push    offset aSSS_0   ; "%s - %s%s"

004785B5                 lea     ecx, [ebp+buffer]

004785BB                 push    ecx             ; buffer

004785BC                 call    _sprintf

004785C1                 add     esp, 14h

004785C4                 lea     eax, [ebp+buffer] ; int

004785CA                 push    eax             ; lpString

004785CB                 mov     edx, hWnd

004785D1                 push    edx             ; hWnd

004785D2                 call    SetWindowTextA

然后OD会对ollydbg.ini文件中的[History],[Arguments]两项进行设置……下面只贴出部分代码

 

00476F08                 lea     edx, [ebx+1]

00476F0B                 push    edx

00476F0C                 lea     ecx, [edi+6DAh]

00476F12                 push    ecx             ; format

00476F13                 lea     eax, [ebp+buffer]

00476F19                 push    eax             ; buffer

00476F1A                 call    _sprintf

00476F1F                 mov     edx, ebx

00476F21                 add     esp, 0Ch

00476F24                 shl     edx, 6

00476F27                 lea     ecx, [ebp+var_518]

00476F2D                 add     edx, ebx

00476F2F                 push    offset FileName ; lpFileName

00476F34                 shl     edx, 2

00476F37                 lea     eax, [ebp+buffer]

00476F3D                 add     edx, ecx

00476F3F                 push    edx             ; lpString

00476F40                 lea     edx, [edi+6E9h]

00476F46                 push    eax             ; lpKeyName

00476F47                 push    edx             ; lpAppName

00476F48                 call    WritePrivateProfileStringA

 

 

接着OD设置程序状态,并退出Dialog对话框…

 

0047860E                 push    0               ; name

00478610                 push    offset byte_4D5A7C ; int

00478615                 call    sub_409370

0047861A                 add     esp, 8

0047861D                 push    3  //设置状态为运行

0047861F                 call    sub_431978

00478624                 pop     ecx

00478625                 push    0               ; nResult

00478627                 push    ebx             ; hDlg

00478628                 call    EndDialog //结束附加窗口

0047862D                 jmp     short loc_47867B

 

 

DebugActiveProcess附加程序后,系统会为进程中的每一个创建线程,向调试器发送CREATE_THREAD_DEBUG_EVENT调试事件,会为进程中的每个动态加载DLL向调试器发送LOAD_DLL_DEBUG_EVENT调试事件..  OD通过WaitForDebugEvent函数获得这些事件,做相应处理,并调用ContinueDebugEvent使程序继续执行…..当这些都做完后,系统恢复进程中的所有线程,并且在第一个线程恢复的时候会执行 一个 断点指令,最后会调用Ntdll.dll中的DbgBreakPoint函数 而根据跟踪得知DbgBreakPoint中的实现 就是一个int3指令;

 

dwDebugEventCode事件处理表:

0042EBF7                 mov     edx, DebugEvent.dwDebugEventCode

0042EBFD                 cmp     edx, 9          ; switch 10 cases

0042EC00                 ja      loc_4313F4      ; default

0042EC00                                         ; jumptable 0042EC06 case 0

0042EC06                 jmp     ds:off_42EC0D[edx*4] ; switch jump

0042EC06 ; ---------------------------------------------------------------------------

0042EC0D off_42EC0D      dd offset loc_4313F4    ; DATA XREF: sub_42EBD0+36r

0042EC0D                 dd offset loc_42EC35    ; jump table for switch 

0042EC0D                 dd offset loc_430CFF

0042EC0D                 dd offset loc_430DD7

0042EC0D                 dd offset loc_430F3F

0042EC0D                 dd offset loc_431037

0042EC0D                 dd offset loc_43112D

0042EC0D                 dd offset loc_4311B7

0042EC0D                 dd offset loc_431276

0042EC0D                 dd offset loc_4313C7

 

DbgBreakPoint的实现

 

7C92120E >  CC              int3     

7C92120F    C3              retn

 

因此当程序执行到此时,会引起一个EXCEPTION_DEBUG_EVENT事件,OD通过WaitForDebugEvent函数会获得此调试事件…OD在获得EXCEPTION_DEBUG_EVENT事件后,之后并没有调用ContinueDebugEvent使程序执行。因此OD会停到DbgBreakPoint处,也就是EIP会指在retn处。