DebugPort 调用过程

DebugPort调用过程

学习各种外挂制作技术，马上去百度搜索"魔鬼作坊"点击第一个站进入、快速成为做挂达人。

1一个程序被ring3调试器调试时，有很多的调试特征可以检测，本论坛也有专门的帖子详细论述，但有个非常根本的标志ring3也是可以检测的比较少人提及，那就是_EPROCESS.DebugPort。DebugPort对于ring3调试器来说非常重要，没有它正常的ring3调试是无法进行的。当然要检测这个标志的前提是程序能够读取ring0内存，在XP 以上的系统有个非常简单的方法就是使用ZwSystemDebugControl的SysDbgReadVirtualMemory方法，我们也可以mapphysicalmemory来操作。检测DebugPort之前首先要得到进程的eprocess地址，这可以通过ZwQuerySystemInformation的SystemHandleInformation方法得到，也可以直接搜索ring0内存的eprocess结构。

对于ring3直接检测DebugPort，我们可以通过禁止该进程访问ring0内存来对付，但是目标一旦使用驱动来检测，那么就非常麻烦了。下面介绍一种隐藏_EPROCESS.DebugPort的方法，这种方法的基本思路是，将一个正常被调试进程的DebugPort置零后，修正所有受影响的函数，使我们的调试器能够正常进行。这些函数如下：

PspCreateProcess、MmCreatePeb进程创建，设置DebugPort

DbgkCreateThread发送线程或者进程创建的调试信息

KiDispatchException、DbgkForwardException和DbgkpQueueMessage发送异常调试信息

PspExitThread、DbgkExitThread和DbgkExitProcess发送线程退出、进程退出的调试信息

DbgkMapViewOfSection和DbgkUnMapViewOfSection发送映像装载卸载调试信息

DbgkpSetProcessDebugObject和DbgkpMarkProcessPeb当调试器附加进程时设置DebugPort

这类函数非常多的，如果都HOOK处理的话，那太恐怖了，这里使用一个非常简单的办法：偷龙转凤。我们看系统访问DebugPort的代码都是这样的（XP）

8b89bc000000mov ecx,dword ptr[ecx+0BCh]//0BCh就是DebugPort的偏移

我们可以把DebugPort转移到_EPROCESS的另外一个地方，比如我使用+0x070CreateTime，它是纪录进程创建时间的，进程创建之后，在进程退出前系统不会对它进行任何修改，而且我们修改后对系统或进程没有任何影响。这样我们可以把上面的代码改成这样

8b8970000000mov ecx,dword ptr[ecx+070h]//指向CreateTime，实际的DebugPort已经被移到这里

只需要修改一个字节，非常简单。

当然这种方法最麻烦的地方就是定位引用到DebugPort的函数（本人仅仅针对不同的XP系统制作特征码都累到吐血），这些函数都是不导出的，如果是特定系统，最简单的方法就是WinDbg->uf***直接找地址硬编码，只需要几分钟时间。

BOOLEAN InitHackAddress()

2{

3_SEH_TRY

4{

5g_KernelBase=GetKernelBaseAndSize(&g_KernelSize);

6g_HackPspCreateProcess= SearchHackPspCreateProcess(&g_NopPspCreateProcess.Address);

7g_HackKiDispatchException

=SearchKiDispatchException(g_KernelBase,g_KernelSize);

8g_HackDbgkpQueueMessage= SearchDbgkpQueueMessage(g_KernelBase,g_KernelSize);

9g_HackDbgkCreateThread= SearchDbgkCreateThread(g_KernelBase,g_KernelSize);

10SearchDbgkNotifyRoutine(g_KernelBase,g_KernelSize);

11g_HackPspExitThread=SearchPspExitThread();

12g_HackMmCreatePeb=SearchMmCreatePeb(g_HackPspCreateProcess); 13SearchDbgkpSetProcessDebugObject(g_KernelBase,g_KernelSize);

14if(g_HackDbgkpSetProcessDebugObject[3])

15g_HackDbgkpMarkProcessPeb= SearchDbgkpMarkProcessPeb(g_HackDbgkpSetProcessDebugObject[3]);

16

17if(g_NopPspCreateProcess.Address!=0){

18

RtlFillMemory(g_NopPspCreateProcess.NopCode,sizeof(g_NopPspCreateProcess. NopCode),0x90);

19g_NopPspCreateProcess.Size=9;

20

RtlCopyMemory(g_NopPspCreateProcess.OrigCode,(PVOID)g_NopPspCreateProce ss.Address,g_NopPspCreateProcess.Size);

21}

22if(g_NopDbgkForwardException.Address!=0){

23

RtlFillMemory(g_NopDbgkForwardException.NopCode,sizeof(g_NopDbgkForwardE xception.NopCode),0x90);

24

RtlCopyMemory(g_NopDbgkForwardException.OrigCode,(PVOID)g_NopDbgkForwa rdException.Address,g_NopDbgkForwardException.Size);

25}

26if(g_NopDbgkExitThread.Address!=0){

27

RtlFillMemory(g_NopDbgkExitThread.NopCode,sizeof(g_NopDbgkExitThread.NopC ode),0x90);

28

RtlCopyMemory(g_NopDbgkExitThread.OrigCode,(PVOID)g_NopDbgkExitThread.A ddress,g_NopDbgkExitThread.Size);

29}

30if(g_NopDbgkExitProcess.Address!=0){

31

RtlFillMemory(g_NopDbgkExitProcess.NopCode,sizeof(g_NopDbgkExitProcess.Nop Code),0x90);

32

RtlCopyMemory(g_NopDbgkExitProcess.OrigCode,(PVOID)g_NopDbgkExitProcess. Address,g_NopDbgkExitProcess.Size);

33}

34if(g_NopDbgkMapViewOfSection.Address!=0){

35

RtlFillMemory(g_NopDbgkMapViewOfSection.NopCode,sizeof(g_NopDbgkMapView OfSection.NopCode),0x90);

36

RtlCopyMemory(g_NopDbgkMapViewOfSection.OrigCode,(PVOID)g_NopDbgkMapV iewOfSection.Address,g_NopDbgkMapViewOfSection.Size);

37}

38if(g_NopDbgkUnMapViewOfSection.Address!=0){

39

RtlFillMemory(g_NopDbgkUnMapViewOfSection.NopCode,sizeof(g_NopDbgkUnMa pViewOfSection.NopCode),0x90);

40

RtlCopyMemory(g_NopDbgkUnMapViewOfSection.OrigCode,(PVOID)g_NopDbgkUn MapViewOfSection.Address,g_NopDbgkUnMapViewOfSection.Size);

41}

42

43

44}

45_SEH_HANDLER

46{

47DbgPrint("InitHackAddress Exception!\n");

48}

49return(g_HackPspCreateProcess!=0&&

50g_HackKiDispatchException!=0&&

51g_HackDbgkForwardException!=0&&

52g_HackDbgkpQueueMessage!=0&&

53g_NopPspCreateProcess.Address!=0&&

54g_NopDbgkForwardException.Address!=0&&

55g_HackDbgkCreateThread!=0&&

56g_HackDbgkExitThread!=0&&

57g_NopDbgkExitThread.Address!=0&&

58g_HackDbgkExitProcess!=0&&

59g_NopDbgkExitProcess.Address!=0&&

60g_HackDbgkMapViewOfSection!=0&&

61g_NopDbgkMapViewOfSection.Address!=0&&

62g_HackDbgkUnMapViewOfSection!=0&&

63g_NopDbgkUnMapViewOfSection.Address!=0&&

64g_HackPspExitThread!=0&&

65g_HackMmCreatePeb!=0&&

66g_HackDbgkpSetProcessDebugObject[0]!=0&&

67g_HackDbgkpSetProcessDebugObject[1]!=0&&

68g_HackDbgkpSetProcessDebugObject[2]!=0&&

69g_HackDbgkpSetProcessDebugObject[3]!=0&&

70g_HackDbgkpMarkProcessPeb!=0);

71}//修改已经运行进程的DebugPort位置

72BOOLEAN ChangeProcessDebugPort(BOOLEAN Hide)

73{

74ULONG eProcess=(ULONG)PsInitialSystemProcess;

75PLIST_ENTRY pListHead,pListWalk;

76ULONG DebugObject;

77if(!g_bIsAddressStartup){

78return FALSE;

79}

80pListHead=(PLIST_ENTRY)(eProcess+ACTIVE_LINKS_OFFSET);

81pListWalk=pListHead;

82_SEH_TRY

83{

84do{

85if(pListWalk==NULL||eProcess==0)

86break;

87eProcess=((ULONG)pListWalk-ACTIVE_LINKS_OFFSET);

88if(Hide){

89DebugObject=*(ULONG*)(eProcess+DEBUG_PORT_OFFSET); 90*(ULONG*)(eProcess+CREATE_TIME_OFFSET)=DebugObject; 91*(ULONG*)(eProcess+DEBUG_PORT_OFFSET)=0;

92}else{

93DebugObject=*(ULONG*)(eProcess+CREATE_TIME_OFFSET); 94*(ULONG*)(eProcess+DEBUG_PORT_OFFSET)=DebugObject; 95}

96pListWalk=pListWalk->Flink;

97}while(pListWalk!=pListHead);

98}

99_SEH_HANDLER

100{

101DbgPrint("ChangeProcessDebugPortexception!\n");

102}

103

104return TRUE;

105}

106代码:

107BOOLEANModifyDebugFunction()

108{

109if(!g_bIsAddressStartup){

110returnFALSE;

111}

112__asm{

113cli

114mov eax,cr0

115and eax,not10000h

116mov cr0,eax

117}

118*(ULONG*)g_HackPspCreateProcess=CREATE_TIME_OFFSET;

119*(ULONG*)g_HackKiDispatchException=CREATE_TIME_OFFSET;

120*(ULONG*)g_HackDbgkForwardException=CREATE_TIME_OFFSET;

121*(ULONG*)g_HackDbgkpQueueMessage=CREATE_TIME_OFFSET;

122*(ULONG*)g_HackDbgkCreateThread=CREATE_TIME_OFFSET;

123*(ULONG*)g_HackDbgkExitThread=CREATE_TIME_OFFSET;

124*(ULONG*)g_HackDbgkExitProcess=CREATE_TIME_OFFSET;

125*(ULONG*)g_HackDbgkMapViewOfSection=CREATE_TIME_OFFSET;

126*(ULONG*)g_HackDbgkUnMapViewOfSection=CREATE_TIME_OFFSET;

127*(ULONG*)g_HackPspExitThread=CREATE_TIME_OFFSET;

128*(ULONG*)g_HackDbgkpMarkProcessPeb=CREATE_TIME_OFFSET;

129*(ULONG*)g_HackMmCreatePeb=CREATE_TIME_OFFSET;

130*(ULONG*)g_HackDbgkpSetProcessDebugObject[0]= CREATE_TIME_OFFSET;

131*(ULONG*)g_HackDbgkpSetProcessDebugObject[1]= CREATE_TIME_OFFSET;

132*(ULONG*)g_HackDbgkpSetProcessDebugObject[2]= CREATE_TIME_OFFSET;

133*(ULONG*)g_HackDbgkpSetProcessDebugObject[3]= CREATE_TIME_OFFSET;

134

135

RtlCopyMemory((PVOID)g_NopPspCreateProcess.Address,g_NopPspCreateProces s.NopCode,g_NopPspCreateProcess.Size);

136

RtlCopyMemory((PVOID)g_NopDbgkForwardException.Address,g_NopDbgkForward Exception.NopCode,g_NopDbgkForwardException.Size);

137

RtlCopyMemory((PVOID)g_NopDbgkExitThread.Address,g_NopDbgkExitThread.No pCode,g_NopDbgkExitThread.Size);

138

RtlCopyMemory((PVOID)g_NopDbgkExitProcess.Address,g_NopDbgkExitProcess.N opCode,g_NopDbgkExitProcess.Size);

139

RtlCopyMemory((PVOID)g_NopDbgkMapViewOfSection.Address,g_NopDbgkMapVi ewOfSection.NopCode,g_NopDbgkMapViewOfSection.Size);

140

RtlCopyMemory((PVOID)g_NopDbgkUnMapViewOfSection.Address,g_NopDbgkUn MapViewOfSection.NopCode,g_NopDbgkUnMapViewOfSection.Size);

141__asm{

142mov eax,cr0

143or eax,10000h

144mov cr0,eax

145sti

146}

147return TRUE;

148}

149BOOLEAN WriteBackDebugFunction()

150{

151if(!g_bIsAddressStartup){

152return FALSE;

153}

154__asm{

155cli

156mov eax,cr0

157and eax,not10000h

158mov cr0,eax

159}

160*(ULONG*)g_HackPspCreateProcess=DEBUG_PORT_OFFSET;

161*(ULONG*)g_HackKiDispatchException=DEBUG_PORT_OFFSET;

162*(ULONG*)g_HackDbgkForwardException=DEBUG_PORT_OFFSET;

163*(ULONG*)g_HackDbgkpQueueMessage=DEBUG_PORT_OFFSET;

164*(ULONG*)g_HackDbgkCreateThread=DEBUG_PORT_OFFSET;

165*(ULONG*)g_HackDbgkExitThread=DEBUG_PORT_OFFSET;

166*(ULONG*)g_HackDbgkExitProcess=DEBUG_PORT_OFFSET;

167*(ULONG*)g_HackDbgkMapViewOfSection=DEBUG_PORT_OFFSET;

168*(ULONG*)g_HackDbgkUnMapViewOfSection=DEBUG_PORT_OFFSET;

169*(ULONG*)g_HackPspExitThread=DEBUG_PORT_OFFSET;

170*(ULONG*)g_HackDbgkpMarkProcessPeb=DEBUG_PORT_OFFSET;

171*(ULONG*)g_HackMmCreatePeb=DEBUG_PORT_OFFSET;

172*(ULONG*)g_HackDbgkpSetProcessDebugObject[0]= DEBUG_PORT_OFFSET;

173*(ULONG*)g_HackDbgkpSetProcessDebugObject[1]= DEBUG_PORT_OFFSET;

174*(ULONG*)g_HackDbgkpSetProcessDebugObject[2]= DEBUG_PORT_OFFSET;

175*(ULONG*)g_HackDbgkpSetProcessDebugObject[3]= DEBUG_PORT_OFFSET;

176

RtlCopyMemory((PVOID)g_NopPspCreateProcess.Address,g_NopPspCreateProces s.OrigCode,g_NopPspCreateProcess.Size);

177

RtlCopyMemory((PVOID)g_NopDbgkForwardException.Address,g_NopDbgkForward Exception.OrigCode,g_NopDbgkForwardException.Size);

178

RtlCopyMemory((PVOID)g_NopDbgkExitThread.Address,g_NopDbgkExitThread.Ori gCode,g_NopDbgkExitThread.Size);

179

RtlCopyMemory((PVOID)g_NopDbgkExitProcess.Address,g_NopDbgkExitProcess.O rigCode,g_NopDbgkExitProcess.Size);

180

RtlCopyMemory((PVOID)g_NopDbgkMapViewOfSection.Address,g_NopDbgkMapVi ewOfSection.OrigCode,g_NopDbgkMapViewOfSection.Size);

181

RtlCopyMemory((PVOID)g_NopDbgkUnMapViewOfSection.Address,g_NopDbgkUn MapViewOfSection.OrigCode,g_NopDbgkUnMapViewOfSection.Size);

182__asm{

183mov eax,cr0

184or eax,10000h

185mov cr0,eax

186sti

187}

188return TRUE;

189}

我想再嗦一下，上面代码大家看到很多函数有个NOPCode，这个实际上是对付线程PS_C ROSS_THREAD_FLAGS_HIDEFROMDBG的，NOP掉相关地方后，就算线程被设置为T hreadHideFromDebugger也无法阻挡调试器接收调试信息。