PEB(Process Environment Block)와 TEB(Thread Environment Block)

- PEB란 ? Windows Kernel에서 프로세스에 대한 환경 정보를 담고 있는 구조체이다. 각 프로세스마다 PEB가 있고 각 프로세스 마다 가지고 있는 스레드 마다 TEB(Thread Environment Block)을 가지고 있습니다.PEB,TEB모두 커널모드에서는 존재하지 않습니다. 모두 유저모드 프로세스 하나당, 유저모드 스레드 하나당 존재하게 됩니다.

[사진 1]

-window xp 기준 PEB구조

nt!_PEB
   +0x000 InheritedAddressSpace : UChar
   +0x001 ReadImageFileExecOptions : UChar
   +0x002 BeingDebugged    : UChar
   +0x003 SpareBool        : UChar
   +0x004 Mutant           : Ptr32 Void
   +0x008 ImageBaseAddress : Ptr32 Void
   +0x00c Ldr              : Ptr32 _PEB_LDR_DATA
   +0x010 ProcessParameters : Ptr32 _RTL_USER_PROCESS_PARAMETERS
   +0x014 SubSystemData    : Ptr32 Void
   +0x018 ProcessHeap      : Ptr32 Void
   +0x01c FastPebLock      : Ptr32 _RTL_CRITICAL_SECTION
   +0x020 FastPebLockRoutine : Ptr32 Void
   +0x024 FastPebUnlockRoutine : Ptr32 Void
   +0x028 EnvironmentUpdateCount : Uint4B
   +0x02c KernelCallbackTable : Ptr32 Void
   +0x030 SystemReserved   : [1] Uint4B
   +0x034 AtlThunkSListPtr32 : Uint4B
   +0x038 FreeList         : Ptr32 _PEB_FREE_BLOCK
   +0x03c TlsExpansionCounter : Uint4B
   +0x040 TlsBitmap        : Ptr32 Void
   +0x044 TlsBitmapBits    : [2] Uint4B
   +0x04c ReadOnlySharedMemoryBase : Ptr32 Void
   +0x050 ReadOnlySharedMemoryHeap : Ptr32 Void
   +0x054 ReadOnlyStaticServerData : Ptr32 Ptr32 Void
   +0x058 AnsiCodePageData : Ptr32 Void
   +0x05c OemCodePageData  : Ptr32 Void
   +0x060 UnicodeCaseTableData : Ptr32 Void
   +0x064 NumberOfProcessors : Uint4B
   +0x068 NtGlobalFlag     : Uint4B
   +0x070 CriticalSectionTimeout : _LARGE_INTEGER
   +0x078 HeapSegmentReserve : Uint4B
   +0x07c HeapSegmentCommit : Uint4B
   +0x080 HeapDeCommitTotalFreeThreshold : Uint4B
   +0x084 HeapDeCommitFreeBlockThreshold : Uint4B
   +0x088 NumberOfHeaps    : Uint4B
   +0x08c MaximumNumberOfHeaps : Uint4B
   +0x090 ProcessHeaps     : Ptr32 Ptr32 Void
   +0x094 GdiSharedHandleTable : Ptr32 Void
   +0x098 ProcessStarterHelper : Ptr32 Void
   +0x09c GdiDCAttributeList : Uint4B
   +0x0a0 LoaderLock       : Ptr32 Void
   +0x0a4 OSMajorVersion   : Uint4B
   +0x0a8 OSMinorVersion   : Uint4B
   +0x0ac OSBuildNumber    : Uint2B
   +0x0ae OSCSDVersion     : Uint2B
   +0x0b0 OSPlatformId     : Uint4B
   +0x0b4 ImageSubsystem   : Uint4B
   +0x0b8 ImageSubsystemMajorVersion : Uint4B
   +0x0bc ImageSubsystemMinorVersion : Uint4B
   +0x0c0 ImageProcessAffinityMask : Uint4B
   +0x0c4 GdiHandleBuffer  : [34] Uint4B
   +0x14c PostProcessInitRoutine : Ptr32     void 
   +0x150 TlsExpansionBitmap : Ptr32 Void
   +0x154 TlsExpansionBitmapBits : [32] Uint4B
   +0x1d4 SessionId        : Uint4B
   +0x1d8 AppCompatFlags   : _ULARGE_INTEGER
   +0x1e0 AppCompatFlagsUser : _ULARGE_INTEGER
   +0x1e8 pShimData        : Ptr32 Void
   +0x1ec AppCompatInfo    : Ptr32 Void
   +0x1f0 CSDVersion       : _UNICODE_STRING
   +0x1f8 ActivationContextData : Ptr32 Void
   +0x1fc ProcessAssemblyStorageMap : Ptr32 Void
   +0x200 SystemDefaultActivationContextData : Ptr32 Void
   +0x204 SystemAssemblyStorageMap : Ptr32 Void
   +0x208 MinimumStackCommit : Uint4B

1.+0x002 BeingDebugged    : UChar

- 디버거 존재 여부를 반환 (IsDebuggerPresent() API에서 사용)

2.+0x008 ImageBaseAddress : Ptr32 Void

- 프로세스 메인 module Base Address저장 (GetModuleHandle / LdrGetDllHandle()에서 사용)

3.+0x00c Ldr              : Ptr32 _PEB_LDR_DATA

- 프로세스의 로드된 DLL 목록 저장 (GetModuleHandle / LdrGetDllHandle()에서 사용)

4.+0x018 ProcessHeap      : Ptr32 Void

- 디버거 존재 여부를 조사하는데 쓰일 수 있다. 찾아보니 이것을 가지고 anti-debugging 하는 기법이 있네요.

5.+0x068 NtGlobalFlag     : Uint4B

- 이것 또한 디버거 존재 여부를 조사하는데 쓰일 수 있습니다.

-window xp기준 TEB

nt!_TEB
   +0x000 NtTib            : _NT_TIB
   +0x01c EnvironmentPointer : Ptr32 Void
   +0x020 ClientId         : _CLIENT_ID
   +0x028 ActiveRpcHandle  : Ptr32 Void
   +0x02c ThreadLocalStoragePointer : Ptr32 Void
   +0x030 ProcessEnvironmentBlock : Ptr32 _PEB
   +0x034 LastErrorValue   : Uint4B
   +0x038 CountOfOwnedCriticalSections : Uint4B
   +0x03c CsrClientThread  : Ptr32 Void
   +0x040 Win32ThreadInfo  : Ptr32 Void
   +0x044 User32Reserved   : [26] Uint4B
   +0x0ac UserReserved     : [5] Uint4B
   +0x0c0 WOW32Reserved    : Ptr32 Void
   +0x0c4 CurrentLocale    : Uint4B
   +0x0c8 FpSoftwareStatusRegister : Uint4B
   +0x0cc SystemReserved1  : [54] Ptr32 Void
   +0x1a4 ExceptionCode    : Int4B
   +0x1a8 ActivationContextStack : _ACTIVATION_CONTEXT_STACK
   +0x1bc SpareBytes1      : [24] UChar
   +0x1d4 GdiTebBatch      : _GDI_TEB_BATCH
   +0x6b4 RealClientId     : _CLIENT_ID
   +0x6bc GdiCachedProcessHandle : Ptr32 Void
   +0x6c0 GdiClientPID     : Uint4B
   +0x6c4 GdiClientTID     : Uint4B
   +0x6c8 GdiThreadLocalInfo : Ptr32 Void
   +0x6cc Win32ClientInfo  : [62] Uint4B
   +0x7c4 glDispatchTable  : [233] Ptr32 Void
   +0xb68 glReserved1      : [29] Uint4B
   +0xbdc glReserved2      : Ptr32 Void
   +0xbe0 glSectionInfo    : Ptr32 Void
   +0xbe4 glSection        : Ptr32 Void
   +0xbe8 glTable          : Ptr32 Void
   +0xbec glCurrentRC      : Ptr32 Void
   +0xbf0 glContext        : Ptr32 Void
   +0xbf4 LastStatusValue  : Uint4B
   +0xbf8 StaticUnicodeString : _UNICODE_STRING
   +0xc00 StaticUnicodeBuffer : [261] Uint2B
   +0xe0c DeallocationStack : Ptr32 Void
   +0xe10 TlsSlots         : [64] Ptr32 Void
   +0xf10 TlsLinks         : _LIST_ENTRY
   +0xf18 Vdm              : Ptr32 Void
   +0xf1c ReservedForNtRpc : Ptr32 Void
   +0xf20 DbgSsReserved    : [2] Ptr32 Void
   +0xf28 HardErrorsAreDisabled : Uint4B
   +0xf2c Instrumentation  : [16] Ptr32 Void
   +0xf6c WinSockData      : Ptr32 Void
   +0xf70 GdiBatchCount    : Uint4B
   +0xf74 InDbgPrint       : UChar
   +0xf75 FreeStackOnTermination : UChar
   +0xf76 HasFiberData     : UChar
   +0xf77 IdealProcessor   : UChar
   +0xf78 Spare3           : Uint4B
   +0xf7c ReservedForPerf  : Ptr32 Void
   +0xf80 ReservedForOle   : Ptr32 Void
   +0xf84 WaitingOnLoaderLock : Uint4B
   +0xf88 Wx86Thread       : _Wx86ThreadState
   +0xf94 TlsExpansionSlots : Ptr32 Ptr32 Void
   +0xf98 ImpersonationLocale : Uint4B
   +0xf9c IsImpersonating  : Uint4B
   +0xfa0 NlsCache         : Ptr32 Void
   +0xfa4 pShimData        : Ptr32 Void
   +0xfa8 HeapVirtualAffinity : Uint4B
   +0xfac CurrentTransactionHandle : Ptr32 Void
   +0xfb0 ActiveFrame      : Ptr32 _TEB_ACTIVE_FRAME
   +0xfb4 SafeThunkCall    : UChar
   +0xfb5 BooleanSpare     : [3] UChar

1.+0x000 NtTib            : _NT_TIB

- SEH(Structured Exception Handler) 체인 중 최상위 엔트리를 말합니다.

2.+0x01c EnvironmentPointer : Ptr32 Void

- CreateProcess()의 Environment 필드에 의해 지시된 포인터 값입니다.

3.+0x020 ClientId         : _CLIENT_ID

- 프로세스 아이디와 스레드 아이디를 가지고 있는 필드(CLIENT_ID structurec)

4.+0x02c ThreadLocalStoragePointer : Ptr32 Void

- TlsAlloc/TlsGetValue/TlsSetValue 등의 win32 API에 의해 참조되는 값으로, Thread Loacal Storage(TLS) pointer를 지정합니다.

5.+0x030 ProcessEnvironmentBlock : Ptr32 _PEB

-PEB(Process Environment Bloc) 포인터를 저장합니다.

6.+0x040 Win32ThreadInfo  : Ptr32 Void

-스레드 정보를 담고 있는 커널 모드 포인터 입니다.

-참고 자료

http://anster.egloos.com/viewer/2128538

http://deguls.tistory.com/entry/Windows-TEBThread-Environment-Block-%EC%82%B4%ED%8E%B4%EB%B3%B4%EA%B8%B0

http://gogil.kr/24