擦除模块痕迹

对于擦除模块痕迹,我实验了两种方法,下面一一阐述:

1.修改PEB结构,用代码说话

typedef  struct  _PEB_LDR_DATA
  ... {
  ULONG               Length;
  BOOLEAN             Initialized;
  BYTE    reserved[3];
  PVOID               SsHandle;
  LIST_ENTRY          InLoadOrderModuleList;
  LIST_ENTRY          InMemoryOrderModuleList;
  LIST_ENTRY          InInitializationOrderModuleList;
 }  PEB_LDR_DATA,  * PPEB_LDR_DATA;

 typedef  struct  _UNICODE_STRING
  ... {
  USHORT Length;
  USHORT MaximumLength;
  PWSTR Buffer;
 }  UNICODE_STRING,  * PUNICODE_STRING;

 typedef  struct  _LDR_MODULE  ... {
  LIST_ENTRY InLoadOrderModuleList;
  LIST_ENTRY InMemoryOrderModuleList;
  LIST_ENTRY InInitializationOrderModuleList;
  PVOID BaseAddress;
  PVOID EntryPoint;
  ULONG SizeOfImage;
  UNICODE_STRING FullDllName;
  UNICODE_STRING BaseDllName;
  ULONG Flags;
  SHORT LoadCount;
  SHORT TlsIndex;
  LIST_ENTRY HashTableEntry;
  ULONG TimeDateStamp;
 }  LDR_MODULE,  * PLDR_MODULE;


 typedef  struct  RTL_DRIVE_LETTER_CURDIR
  ... {
  USHORT              Flags;
  USHORT              Length;
  ULONG               TimeStamp;
  UNICODE_STRING      DosPath;
 }  RTL_DRIVE_LETTER_CURDIR,  * PRTL_DRIVE_LETTER_CURDIR;

 typedef  struct  _RTL_USER_PROCESS_PARAMETERS
  ... {
  ULONG               AllocationSize;
  ULONG               Size;
  ULONG               Flags;
  ULONG               DebugFlags;
  HANDLE              hConsole;
  ULONG               ProcessGroup;
  HANDLE              hStdInput;
  HANDLE              hStdOutput;
  HANDLE              hStdError;
  UNICODE_STRING      CurrentDirectoryName;
  HANDLE              CurrentDirectoryHandle;
  UNICODE_STRING      DllPath;
  UNICODE_STRING      ImagePathName;
  UNICODE_STRING      CommandLine;
  PWSTR               Environment;
  ULONG               dwX;
  ULONG               dwY;
  ULONG               dwXSize;
  ULONG               dwYSize;
  ULONG               dwXCountChars;
  ULONG               dwYCountChars;
  ULONG               dwFillAttribute;
  ULONG               dwFlags;
  ULONG               wShowWindow;
  UNICODE_STRING      WindowTitle;
  UNICODE_STRING      Desktop;
  UNICODE_STRING      ShellInfo;
  UNICODE_STRING      RuntimeInfo;
  RTL_DRIVE_LETTER_CURDIR DLCurrentDirectory[0x20];
 }  RTL_USER_PROCESS_PARAMETERS,  * PRTL_USER_PROCESS_PARAMETERS;

 typedef VOID (_stdcall  * PPEBLOCKROUTINE)(PVOID);

 typedef  struct  _PEB_FREE_BLOCK
  ... {
  struct _PEB_FREE_BLOCK* Next;
  ULONG Size;
 }  PEB_FREE_BLOCK,  * PPEB_FREE_BLOCK;

  struct  _NT_PEB 
  ... {
  BOOLEAN InheritedAddressSpace;
  BOOLEAN ReadImageFileExecOptions;
  BOOLEAN BeingDebugged;
  BOOLEAN Spare;
  HANDLE Mutant;
  PVOID ImageBaseAddress;
  PPEB_LDR_DATA LoaderData;
  PRTL_USER_PROCESS_PARAMETERS ProcessParameters;
  PVOID SubSystemData;
  PVOID ProcessHeap;
  PVOID FastPebLock;
  PPEBLOCKROUTINE FastPebLockRoutine;
  PPEBLOCKROUTINE FastPebUnlockRoutine;
  ULONG EnvironmentUpdateCount;
  PVOID *KernelCallbackTable;
  PVOID EventLogSection;
  PVOID EventLog;
  PPEB_FREE_BLOCK FreeList;
  ULONG TlsExpansionCounter;
  PVOID TlsBitmap;
  ULONG TlsBitmapBits[0x2];
  PVOID ReadOnlySharedMemoryBase;
  PVOID ReadOnlySharedMemoryHeap;
  PVOID *ReadOnlyStaticServerData;
  PVOID AnsiCodePageData;
  PVOID OemCodePageData;
  PVOID UnicodeCaseTableData;
  ULONG NumberOfProcessors;
  ULONG NtGlobalFlag;
  BYTE Spare2[0x4];
  LARGE_INTEGER CriticalSectionTimeout;
  ULONG HeapSegmentReserve;
  ULONG HeapSegmentCommit;
  ULONG HeapDeCommitTotalFreeThreshold;
  ULONG HeapDeCommitFreeBlockThreshold;
  ULONG NumberOfHeaps;
  ULONG MaximumNumberOfHeaps;
  PVOID **ProcessHeaps;
  PVOID GdiSharedHandleTable;
  PVOID ProcessStarterHelper;
  PVOID GdiDCAttributeList;
  PVOID LoaderLock;
  ULONG OSMajorVersion;
  ULONG OSMinorVersion;
  ULONG OSBuildNumber;
  ULONG OSPlatformId;
  ULONG ImageSubSystem;
  ULONG ImageSubSystemMajorVersion;
  ULONG ImageSubSystemMinorVersion;
  ULONG GdiHandleBuffer[0x22];
  ULONG PostProcessInitRoutine;
  ULONG TlsExpansionBitmap;
  BYTE TlsExpansionBitmapBits[0x80];
  ULONG SessionId;
 } ;

 typedef  struct  _CLIENT_ID
  ... {
  HANDLE UniqueProcess;
  HANDLE UniqueThread;
 }  CLIENT_ID,  * PCLIENT_ID;

 typedef  struct  _GDI_TEB_BATCH
  ... {
  ULONG Offset;
  ULONG HDC;
  ULONG Buffer[0x136];
 }  GDI_TEB_BATCH,  * PGDI_TEB_BATCH;

  struct  _NT_TEB
  ... {
  NT_TIB Tib;                         /**//* 00h */
  PVOID EnvironmentPointer;           /**//* 1Ch */
  CLIENT_ID Cid;                      /**//* 20h */
  PVOID ActiveRpcInfo;                /**//* 28h */
  PVOID ThreadLocalStoragePointer;    /**//* 2Ch */
  _NT_PEB *Peb;                       /**//* 30h */
  ULONG LastErrorValue;               /**//* 34h */
  ULONG CountOfOwnedCriticalSections; /**//* 38h */
  PVOID CsrClientThread;              /**//* 3Ch */
  void* Win32ThreadInfo;    /**//* 40h */
  ULONG Win32ClientInfo[0x1F];        /**//* 44h */
  PVOID WOW32Reserved;                /**//* C0h */
  LCID CurrentLocale;                 /**//* C4h */
  ULONG FpSoftwareStatusRegister;     /**//* C8h */
  PVOID SystemReserved1[0x36];        /**//* CCh */
  PVOID Spare1;                       /**//* 1A4h */
  LONG ExceptionCode;                 /**//* 1A8h */
  UCHAR SpareBytes1[0x28];            /**//* 1ACh */
  PVOID SystemReserved2[0xA];         /**//* 1D4h */
  GDI_TEB_BATCH GdiTebBatch;          /**//* 1FCh */
  ULONG gdiRgn;                       /**//* 6DCh */
  ULONG gdiPen;                       /**//* 6E0h */
  ULONG gdiBrush;                     /**//* 6E4h */
  CLIENT_ID RealClientId;             /**//* 6E8h */
  PVOID GdiCachedProcessHandle;       /**//* 6F0h */
  ULONG GdiClientPID;                 /**//* 6F4h */
  ULONG GdiClientTID;                 /**//* 6F8h */
  PVOID GdiThreadLocaleInfo;          /**//* 6FCh */
  PVOID UserReserved[5];              /**//* 700h */
  PVOID glDispatchTable[0x118];       /**//* 714h */
  ULONG glReserved1[0x1A];            /**//* B74h */
  PVOID glReserved2;                  /**//* BDCh */
  PVOID glSectionInfo;                /**//* BE0h */
  PVOID glSection;                    /**//* BE4h */
  PVOID glTable;                      /**//* BE8h */
  PVOID glCurrentRC;                  /**//* BECh */
  PVOID glContext;                    /**//* BF0h */
  LONG LastStatusValue;    /**//* BF4h */
  UNICODE_STRING StaticUnicodeString; /**//* BF8h */
  WCHAR StaticUnicodeBuffer[0x105];   /**//* C00h */
  PVOID DeallocationStack;            /**//* E0Ch */
  PVOID TlsSlots[0x40];               /**//* E10h */
  LIST_ENTRY TlsLinks;                /**//* F10h */
  PVOID Vdm;                          /**//* F18h */
  PVOID ReservedForNtRpc;             /**//* F1Ch */
  PVOID DbgSsReserved[0x2];           /**//* F20h */
  ULONG HardErrorDisabled;            /**//* F28h */
  PVOID Instrumentation[0x10];        /**//* F2Ch */
  PVOID WinSockData;                  /**//* F6Ch */
  ULONG GdiBatchCount;                /**//* F70h */
  USHORT Spare2;                      /**//* F74h */
  BOOLEAN IsFiber;                    /**//* F76h */
  UCHAR Spare3;                       /**//* F77h */
  ULONG Spare4;                       /**//* F78h */
  ULONG Spare5;                       /**//* F7Ch */
  PVOID ReservedForOle;               /**//* F80h */
  ULONG WaitingOnLoaderLock;          /**//* F84h */
  ULONG Unknown[11];                  /**//* F88h */
  PVOID FlsSlots;                     /**//* FB4h */
  PVOID WineDebugInfo;                /**//* Needed for WINE DLL's  */
 } ;

  static   struct  _NT_TEB *  GetCurrentThreadTEB()                      // 获得TEB
  ... {
  struct _NT_TEB *pTeb=NULL;

  _asm
  ...{
   mov  eax,fs:[0x18]
   mov  pTeb,eax
  }
  return pTeb;
 }

  void  HideModule(std:: string  strModuleName)
  ... {
  struct _NT_TEB *pTeb = GetCurrentThreadTEB();
  struct _NT_PEB *pPeb = pTeb->Peb;                                //由TEB获得PEB
  PPEB_LDR_DATA pLdrData = pPeb->LoaderData;
  PLDR_MODULE pFirstLdrModule = (PLDR_MODULE)pLdrData->InLoadOrderModuleList.Flink; 
  PLDR_MODULE pLdrModule = pFirstLdrModule;
  PLDR_MODULE pLastModule,pNextModule;

  //名字通通转为WideChar,因此Windows内部是Unicode的
  WCHAR pWStrModuleName[MAX_PATH] = ...{WCHAR(0)};
  MultiByteToWideChar(CP_ACP,0,strModuleName.c_str(), -1,pWStrModuleName,strModuleName.size()); 

  //PEB里面有当前进程的模块列表,ToolHelp里面的函数就是根据这个列表来遍历的因此,修改此列表可以达到隐藏的目的
  do 
  ...{
   //判断是否是我们要屏蔽的模块
   if(wcscmp(pLdrModule->BaseDllName.Buffer, pWStrModuleName) == 0)
   ...{
    //更改指针,达到隐藏的目的
    pLastModule = (PLDR_MODULE)(pLdrModule->InLoadOrderModuleList.Blink);
    pNextModule = (PLDR_MODULE)(pLdrModule->InLoadOrderModuleList.Flink);
    pLastModule->InLoadOrderModuleList.Flink = (PLIST_ENTRY)pNextModule;
    pNextModule->InLoadOrderModuleList.Blink = (PLIST_ENTRY)pLastModule;

    //因为PEB里面有三个列表(分别是以Load顺序、地址顺序、初始化顺序来排序),所以通过覆盖的方式修改另外两个列表,达到隐藏的目的
    pLdrModule->BaseAddress = pLastModule->BaseAddress;
    pLdrModule->BaseDllName = pLastModule->BaseDllName;
    pLdrModule->EntryPoint = pLastModule->EntryPoint;
    pLdrModule->Flags = pLastModule->Flags;
    pLdrModule->FullDllName = pLastModule->FullDllName;
    pLdrModule->HashTableEntry = pLastModule->HashTableEntry;
    pLdrModule->LoadCount = pLastModule->LoadCount;
    pLdrModule->SizeOfImage = pLastModule->SizeOfImage;
    pLdrModule->TimeDateStamp = pLastModule->TimeDateStamp;
    pLdrModule->TlsIndex = pLastModule->TlsIndex;
   }
   pLdrModule = (PLDR_MODULE)pLdrModule->InLoadOrderModuleList.Flink;

  } while(pLdrModule != pFirstLdrModule);
 }

 2.手动完成dll的加载：刚开始研究手动加载的时候觉得比较复杂，但是通过实践之后，其实还是很简单的，代码比较长这里就不详加叙述了，我就用下面几个步骤来分别叙述：

• 首先要分配一个空间给dll,可以根据PE结构里面的SizeOfImage来分配；
• 然后把dll加载到分配的空间里面去，需要注意的是不能单纯拷贝，对于每个Section而言，需要安排到Section列表里面指定的虚拟地址偏移里面去（即RAV + 分配到的空间开始地址<可以称为模块句柄>）；
• 然后要做的就是完成IAT的填写（根据INT）以及重定位表的处理
• ok,打完收工（还有些比较复杂的处理我还不太明白，比如TLS，努力学习中）

    因为手动加载dll没有经过系统的干涉，所以上面的PEB结构里面也就不会有相应的模块结构，也就达到了隐藏的目的。