有时候我们需要对其它应用程序发送和接收的网络数据进行拦截,比如要对IE发送的**头进行分析,得到请求的地址等.这次我们可以用一些例如WPE, Sniffer之类的工具来达到目的.但是工具功能有限,要想实现更强大的功能,还是我们自己动手来DIY吧.
拦截网络数据封包的方法有三种,一是将网卡设为混杂模式,这次就可以监视到局域网上所有的数据包,二是HOOK目标进程的发送和接收的API函数,第三种方法是自己实现一个代理的DLL.在这里我们使用HOOK API的方法,这样易于实现,而且也不会得到大量的无用数据(如第一种方法就会监视到所有的网络数据).
下面是一个尽量简化了的API HOOK的模版,原理是利用消息钩子将DLL中的代码注入到目标进程中,再用GetProcAddress得到API函数入口地址,将函数入口址改为自己定义的函数入口,这样就得到了API函数的相应参数,处理完后,再改回真实API函数入口地址,并调用它.
HOOK.DLL的代码:
- library Hook;
- uses
- SysUtils,
- windows,
- Messages,
- APIHook in 'APIHook.pas';
- type
- PData = ^TData;
- TData = record
- Hook: THandle;
- Hooked: Boolean;
- end;
- var
- DLLData: PData;
- {------------------------------------}
- {过程名:HookProc
- {过程功能:HOOK过程
- {过程参数:nCode, wParam, lParam消息的相
- { 关参数
- {------------------------------------}
- procedure HookProc(nCode, wParam, lParam: LongWORD);stdcall;
- begin
- if not DLLData^.Hooked then
- begin
- HookAPI;
- DLLData^.Hooked := True;
- end;
- //调用下一个Hook
- CallNextHookEx(DLLData^.Hook, nCode, wParam, lParam);
- end;
- {------------------------------------}
- {函数名:InstallHook
- {函数功能:在指定窗口上安装HOOK
- {函数参数:sWindow:要安装HOOK的窗口
- {返回值:成功返回TRUE,失败返回FALSE
- {------------------------------------}
- function InstallHook(SWindow: LongWORD):Boolean;stdcall;
- var
- ThreadID: LongWORD;
- begin
- Result := False;
- DLLData^.Hook := 0;
- ThreadID := GetWindowThreadProcessId(sWindow, nil);
- //给指定窗口挂上钩子
- DLLData^.Hook := SetWindowsHookEx(WH_GETMESSAGE, @HookProc, Hinstance, ThreadID);
- if DLLData^.Hook > 0 then
- Result := True //是否成功HOOK
- else
- exit;
- end;
- {------------------------------------}
- {过程名:UnHook
- {过程功能:卸载HOOK
- {过程参数:无
- {------------------------------------}
- procedure UnHook;stdcall;
- begin
- UnHookAPI;
- //卸载Hook
- UnhookWindowsHookEx(DLLData^.Hook);
- end;
- {------------------------------------}
- {过程名:DLL入口函数
- {过程功能:进行DLL初始化,释放等
- {过程参数:DLL状态
- {------------------------------------}
- procedure MyDLLHandler(Reason: Integer);
- var
- FHandle: LongWORD;
- begin
- case Reason of
- DLL_PROCESS_ATTACH:
- begin //建立文件映射,以实现DLL中的全局变量
- FHandle := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE, 0, $ffff, 'MYDLLDATA');
- if FHandle = 0 then
- if GetLastError = ERROR_ALREADY_EXISTS then
- begin
- FHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, 'MYDLLDATA');
- if FHandle = 0 then Exit;
- end else Exit;
- DLLData := MapViewOfFile(FHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
- if DLLData = nil then
- CloseHandle(FHandle);
- end;
- DLL_PROCESS_DETACH:
- begin
- if Assigned(DLLData) then
- begin
- UnmapViewOfFile(DLLData);
- DLLData := nil;
- end;
- end;
- end;
- end;
- {$R *.res}
- exports
- InstallHook, UnHook, HookProc;
- begin
- DLLProc := @MyDLLHandler;
- MyDLLhandler(DLL_PROCESS_ATTACH);
- DLLData^.Hooked := False;
- end.
- ----------------------------------------------------------------------------------------
- APIHook.Pas的代码:
- unit APIHook;
- interface
- uses
- SysUtils,
- Windows, WinSock;
- type
- //要HOOK的API函数定义
- TSockProc = function (s: TSocket; var Buf; len, flags: Integer): Integer; stdcall;
- PJmpCode = ^TJmpCode;
- TJmpCode = packed record
- JmpCode: BYTE;
- Address: TSockProc;
- MovEAX: Array [0..2] of BYTE;
- end;
- //--------------------函数声明---------------------------
- procedure HookAPI;
- procedure UnHookAPI;
- var
- OldSend, OldRecv: TSockProc; //原来的API地址
- JmpCode: TJmpCode;
- OldProc: array [0..1] of TJmpCode;
- AddSend, AddRecv: pointer; //API地址
- TmpJmp: TJmpCode;
- ProcessHandle: THandle;
- implementation
- {---------------------------------------}
- {函数功能:Send函数的HOOK
- {函数参数:同Send
- {函数返回值:integer
- {---------------------------------------}
- function MySend(s: TSocket; var Buf; len, flags: Integer): Integer; stdcall;
- var
- dwSize: cardinal;
- begin
- //这儿进行发送的数据处理
- MessageBeep(1000); //简单的响一声
- //调用直正的Send函数
- WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize);
- Result := OldSend(S, Buf, len, flags);
- JmpCode.Address := @MySend;
- WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, dwSize);
- end;
- {---------------------------------------}
- {函数功能:Recv函数的HOOK
- {函数参数:同Recv
- {函数返回值:integer
- {---------------------------------------}
- function MyRecv(s: TSocket; var Buf; len, flags: Integer): Integer; stdcall;
- var
- dwSize: cardinal;
- begin
- //这儿进行接收的数据处理
- MessageBeep(1000); //简单的响一声
- //调用直正的Recv函数
- WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize);
- Result := OldRecv(S, Buf, len, flags);
- JmpCode.Address := @MyRecv;
- WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, dwSize);
- end;
- {------------------------------------}
- {过程功能:HookAPI
- {过程参数:无
- {------------------------------------}
- procedure HookAPI;
- var
- DLLModule: THandle;
- dwSize: cardinal;
- begin
- ProcessHandle := GetCurrentProcess;
- DLLModule := LoadLibrary('ws2_32.dll');
- AddSend := GetProcAddress(DLLModule, 'send'); //取得API地址
- AddRecv := GetProcAddress(DLLModule, 'recv');
- JmpCode.JmpCode := $B8;
- JmpCode.MovEAX[0] := $FF;
- JmpCode.MovEAX[1] := $E0;
- JmpCode.MovEAX[2] := 0;
- ReadProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize);
- JmpCode.Address := @MySend;
- WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, dwSize); //修改Send入口
- ReadProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize);
- JmpCode.Address := @MyRecv;
- WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, dwSize); //修改Recv入口
- OldSend := AddSend;
- OldRecv := AddRecv;
- end;
- {------------------------------------}
- {过程功能:取消HOOKAPI
- {过程参数:无
- {------------------------------------}
- procedure UnHookAPI;
- var
- dwSize: Cardinal;
- begin
- WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize);
- WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize);
- end;
- end.
library Hook; uses SysUtils, windows, Messages, APIHook in 'APIHook.pas'; type PData = ^TData; TData = record Hook: THandle; Hooked: Boolean; end; var DLLData: PData; {------------------------------------} {过程名:HookProc {过程功能:HOOK过程 {过程参数:nCode, wParam, lParam消息的相 { 关参数 {------------------------------------} procedure HookProc(nCode, wParam, lParam: LongWORD);stdcall; begin if not DLLData^.Hooked then begin HookAPI; DLLData^.Hooked := True; end; //调用下一个Hook CallNextHookEx(DLLData^.Hook, nCode, wParam, lParam); end; {------------------------------------} {函数名:InstallHook {函数功能:在指定窗口上安装HOOK {函数参数:sWindow:要安装HOOK的窗口 {返回值:成功返回TRUE,失败返回FALSE {------------------------------------} function InstallHook(SWindow: LongWORD):Boolean;stdcall; var ThreadID: LongWORD; begin Result := False; DLLData^.Hook := 0; ThreadID := GetWindowThreadProcessId(sWindow, nil); //给指定窗口挂上钩子 DLLData^.Hook := SetWindowsHookEx(WH_GETMESSAGE, @HookProc, Hinstance, ThreadID); if DLLData^.Hook > 0 then Result := True //是否成功HOOK else exit; end; {------------------------------------} {过程名:UnHook {过程功能:卸载HOOK {过程参数:无 {------------------------------------} procedure UnHook;stdcall; begin UnHookAPI; //卸载Hook UnhookWindowsHookEx(DLLData^.Hook); end; {------------------------------------} {过程名:DLL入口函数 {过程功能:进行DLL初始化,释放等 {过程参数:DLL状态 {------------------------------------} procedure MyDLLHandler(Reason: Integer); var FHandle: LongWORD; begin case Reason of DLL_PROCESS_ATTACH: begin //建立文件映射,以实现DLL中的全局变量 FHandle := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE, 0, $ffff, 'MYDLLDATA'); if FHandle = 0 then if GetLastError = ERROR_ALREADY_EXISTS then begin FHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, 'MYDLLDATA'); if FHandle = 0 then Exit; end else Exit; DLLData := MapViewOfFile(FHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0); if DLLData = nil then CloseHandle(FHandle); end; DLL_PROCESS_DETACH: begin if Assigned(DLLData) then begin UnmapViewOfFile(DLLData); DLLData := nil; end; end; end; end; {$R *.res} exports InstallHook, UnHook, HookProc; begin DLLProc := @MyDLLHandler; MyDLLhandler(DLL_PROCESS_ATTACH); DLLData^.Hooked := False; end. ---------------------------------------------------------------------------------------- APIHook.Pas的代码: unit APIHook; interface uses SysUtils, Windows, WinSock; type //要HOOK的API函数定义 TSockProc = function (s: TSocket; var Buf; len, flags: Integer): Integer; stdcall; PJmpCode = ^TJmpCode; TJmpCode = packed record JmpCode: BYTE; Address: TSockProc; MovEAX: Array [0..2] of BYTE; end; //--------------------函数声明--------------------------- procedure HookAPI; procedure UnHookAPI; var OldSend, OldRecv: TSockProc; //原来的API地址 JmpCode: TJmpCode; OldProc: array [0..1] of TJmpCode; AddSend, AddRecv: pointer; //API地址 TmpJmp: TJmpCode; ProcessHandle: THandle; implementation {---------------------------------------} {函数功能:Send函数的HOOK {函数参数:同Send {函数返回值:integer {---------------------------------------} function MySend(s: TSocket; var Buf; len, flags: Integer): Integer; stdcall; var dwSize: cardinal; begin //这儿进行发送的数据处理 MessageBeep(1000); //简单的响一声 //调用直正的Send函数 WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize); Result := OldSend(S, Buf, len, flags); JmpCode.Address := @MySend; WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, dwSize); end; {---------------------------------------} {函数功能:Recv函数的HOOK {函数参数:同Recv {函数返回值:integer {---------------------------------------} function MyRecv(s: TSocket; var Buf; len, flags: Integer): Integer; stdcall; var dwSize: cardinal; begin //这儿进行接收的数据处理 MessageBeep(1000); //简单的响一声 //调用直正的Recv函数 WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize); Result := OldRecv(S, Buf, len, flags); JmpCode.Address := @MyRecv; WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, dwSize); end; {------------------------------------} {过程功能:HookAPI {过程参数:无 {------------------------------------} procedure HookAPI; var DLLModule: THandle; dwSize: cardinal; begin ProcessHandle := GetCurrentProcess; DLLModule := LoadLibrary('ws2_32.dll'); AddSend := GetProcAddress(DLLModule, 'send'); //取得API地址 AddRecv := GetProcAddress(DLLModule, 'recv'); JmpCode.JmpCode := $B8; JmpCode.MovEAX[0] := $FF; JmpCode.MovEAX[1] := $E0; JmpCode.MovEAX[2] := 0; ReadProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize); JmpCode.Address := @MySend; WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, dwSize); //修改Send入口 ReadProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize); JmpCode.Address := @MyRecv; WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, dwSize); //修改Recv入口 OldSend := AddSend; OldRecv := AddRecv; end; {------------------------------------} {过程功能:取消HOOKAPI {过程参数:无 {------------------------------------} procedure UnHookAPI; var dwSize: Cardinal; begin WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize); WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize); end; end.
---------------------------------------------------------------------------------------------
编译这个DLL后,再新建一个程序调用这个DLL的InstallHook并传入目标进程的主窗口句柄就可:
- unit fmMain;
- interface
- uses
- Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
- Dialogs, StdCtrls;
- type
- TForm1 = class(TForm)
- Button1: TButton;
- Button2: TButton;
- Edit1: TEdit;
- procedure Button1Click(Sender: TObject);
- procedure Button2Click(Sender: TObject);
- private
- { Private declarations }
- public
- { Public declarations }
- end;
- var
- Form1: TForm1;
- InstallHook: function (SWindow: THandle):Boolean;stdcall;
- UnHook: procedure;stdcall;
- implementation
- {$R *.dfm}
- procedure TForm1.Button1Click(Sender: TObject);
- var
- ModuleHandle: THandle;
- TmpWndHandle: THandle;
- begin
- TmpWndHandle := 0;
- TmpWndHandle := FindWindow(nil, '目标窗口的标题');
- if not isWindow(TmpWndHandle) then
- begin
- MessageBox(self.Handle, '没有找到窗口', '!!!', MB_OK);
- exit;
- end;
- ModuleHandle := LoadLibrary('Hook.dll');
- @InstallHook := GetProcAddress(ModuleHandle, 'InstallHook');
- @UnHook := GetProcAddress(ModuleHandle, 'UnHook');
- if InstallHook(FindWindow(nil, 'Untitled')) then
- ShowMessage('Hook OK');
- end;
- procedure TForm1.Button2Click(Sender: TObject);
- begin
- UnHook
- end;
- end.