转自Delphi先锋<br><br>拦截其它程序的网络数据封包 <br> [ 作者:pankun(原作) 转贴自:本站原创 点击数:1602 更新时间:2004-3-23 <br> 文章录入:delphilxh ]<br><br> 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HTTP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, <br> 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.<br><br> 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 <br> 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).<br><br> 下面是一个尽量简化了的API <br> 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.<br>HOOK.DLL的代码:<br> library Hook;<br> uses<br> SysUtils,<br> windows,<br> Messages,<br> APIHook in 'APIHook.pas';<br> type<br> PData = ^TData;<br> TData = record<br> Hook: THandle;<br> Hooked: Boolean;<br> end;<br> <br> var<br> DLLData: PData;<br> {------------------------------------}<br> {过程名:HookProc<br> {过程功能:HOOK过程<br> {过程参数:nCode, wParam, lParam消息的相<br> { 关参数<br> {------------------------------------}<br> procedure HookProc(nCode, wParam, lParam: LongWORD);stdcall;<br> begin<br> if not DLLData^.Hooked then<br> begin<br> HookAPI;<br> DLLData^.Hooked := True;<br> end;<br> //调用下一个Hook<br> CallNextHookEx(DLLData^.Hook, nCode, wParam, lParam);<br> end;<br><br> {------------------------------------}<br> {函数名:InstallHook<br> {函数功能:在指定窗口上安装HOOK<br> {函数参数:sWindow:要安装HOOK的窗口<br> {返回值:成功返回TRUE,失败返回FALSE<br> {------------------------------------}<br> function InstallHook(SWindow: LongWORD):Boolean;stdcall;<br> var<br> ThreadID: LongWORD;<br> begin<br> Result := False;<br> DLLData^.Hook := 0;<br> ThreadID := GetWindowThreadProcessId(sWindow, nil);<br> //给指定窗口挂上钩子<br> DLLData^.Hook := SetWindowsHookEx(WH_GETMESSAGE, @HookProc, <br> Hinstance, ThreadID);<br> if DLLData^.Hook > 0 then<br> Result := True //是否成功HOOK<br> else<br> exit;<br> end;<br> {------------------------------------}<br> {过程名:UnHook<br> {过程功能:卸载HOOK<br> {过程参数:无<br> {------------------------------------}<br> procedure UnHook;stdcall;<br> begin<br> UnHookAPI;<br> //卸载Hook<br> UnhookWindowsHookEx(DLLData^.Hook);<br> end;<br> {------------------------------------}<br> {过程名
LL入口函数<br> {过程功能:进行DLL初始化,释放等<br> {过程参数
LL状态<br> {------------------------------------}<br> procedure MyDLLHandler(Reason: Integer);<br> var<br> FHandle: LongWORD;<br> begin<br> case Reason of<br> DLL_PROCESS_ATTACH:<br> begin //建立文件映射,以实现DLL中的全局变量<br> FHandle := CreateFileMapping($FFFFFFFF, nil, <br> PAGE_READWRITE, 0, $ffff, 'MYDLLDATA');<br> if FHandle = 0 then<br> if GetLastError = ERROR_ALREADY_EXISTS then<br> begin<br> FHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, <br> 'MYDLLDATA');<br> if FHandle = 0 then Exit;<br> end else Exit;<br> DLLData := MapViewOfFile(FHandle, FILE_MAP_ALL_ACCESS, <br> 0, 0, 0);<br> if DLLData = nil then<br> CloseHandle(FHandle);<br> end;<br> DLL_PROCESS_DETACH:<br> begin<br> if Assigned(DLLData) then<br> begin<br> UnmapViewOfFile(DLLData);<br> DLLData := nil;<br> end;<br> end;<br> end;<br> end;<br> {$R *.res}<br> exports<br> InstallHook, UnHook, HookProc;<br> begin<br> DLLProc := @MyDLLHandler;<br> MyDLLhandler(DLL_PROCESS_ATTACH);<br> DLLData^.Hooked := False;<br> end.<br><br><br><br><br><br><br><br> ----------------------------------------------------------------------------------------<br> APIHook.Pas的代码:<br> unit APIHook;<br> interface<br> uses<br> SysUtils,<br> Windows, WinSock;<br> type<br> //要HOOK的API函数定义<br> TSockProc = function (s: TSocket; var Buf; len, flags: <br> Integer): Integer; stdcall;<br> PJmpCode = ^TJmpCode;<br> TJmpCode = packed record<br> JmpCode: BYTE;<br> Address: TSockProc;<br> MovEAX: Array [0..2] of BYTE;<br> end;<br> //--------------------函数声明---------------------------<br> procedure HookAPI;<br> procedure UnHookAPI;<br> var<br> OldSend, OldRecv: TSockProc; //原来的API地址<br> JmpCode: TJmpCode;<br> OldProc: array [0..1] of TJmpCode;<br> AddSend, AddRecv: pointer; //API地址<br> TmpJmp: TJmpCode;<br> ProcessHandle: THandle;<br> implementation<br> {---------------------------------------}<br> {函数功能:Send函数的HOOK<br> {函数参数:同Send<br> {函数返回值:integer<br> {---------------------------------------}<br> function MySend(s: TSocket; var Buf; len, flags: Integer): <br> Integer; stdcall;<br> var<br> dwSize: cardinal;<br> begin<br> //这儿进行发送的数据处理<br> MessageBeep(1000); //简单的响一声<br> //调用直正的Send函数<br> WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, <br> dwSize);<br> Result := OldSend(S, Buf, len, flags);<br> JmpCode.Address := @MySend;<br> WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, <br> dwSize);<br> end;<br> {---------------------------------------}<br> {函数功能:Recv函数的HOOK<br> {函数参数:同Recv<br> {函数返回值:integer<br> {---------------------------------------}<br> function MyRecv(s: TSocket; var Buf; len, flags: Integer): <br> Integer; stdcall;<br> var<br> dwSize: cardinal;<br> begin<br> //这儿进行接收的数据处理<br> MessageBeep(1000); //简单的响一声<br> //调用直正的Recv函数<br> WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, <br> dwSize);<br> Result := OldRecv(S, Buf, len, flags);<br> JmpCode.Address := @MyRecv;<br> WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, <br> dwSize);<br> end;<br> {------------------------------------}<br> {过程功能:HookAPI<br> {过程参数:无<br> {------------------------------------}<br> procedure HookAPI;<br> var<br> DLLModule: THandle;<br> dwSize: cardinal;<br> begin<br> ProcessHandle := GetCurrentProcess;<br> DLLModule := LoadLibrary('ws2_32.dll'); <br> AddSend := GetProcAddress(DLLModule, 'send'); //取得API地址<br> AddRecv := GetProcAddress(DLLModule, 'recv');<br> JmpCode.JmpCode := $B8;<br> JmpCode.MovEAX[0] := $FF;<br> JmpCode.MovEAX[1] := $E0;<br> JmpCode.MovEAX[2] := 0;<br> ReadProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, <br> dwSize);<br> JmpCode.Address := @MySend;<br> WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, <br> dwSize); //修改Send入口<br> ReadProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, <br> dwSize);<br> JmpCode.Address := @MyRecv;<br> WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, <br> dwSize); //修改Recv入口<br> OldSend := AddSend;<br> OldRecv := AddRecv;<br> end;<br> {------------------------------------}<br> {过程功能:取消HOOKAPI<br> {过程参数:无<br> {------------------------------------}<br> procedure UnHookAPI;<br> var<br> dwSize: Cardinal;<br> begin<br> WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, <br> dwSize);<br> WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, <br> dwSize);<br> end;<br> end.<br><br><br><br><br><br><br><br><br><br> ---------------------------------------------------------------------------------------------<br> 编译这个DLL后,再新建一个程序调用这个DLL的InstallHook并传入目标进程的主窗口句柄就可:<br> unit fmMain;<br> interface<br> uses<br> Windows, Messages, SysUtils, Variants, Classes, Graphics, <br> Controls, Forms,<br> Dialogs, StdCtrls;<br> type<br> TForm1 = class(TForm)<br> Button1: TButton;<br> Button2: TButton;<br> Edit1: TEdit;<br> procedure Button1Click(Sender: TObject);<br> procedure Button2Click(Sender: TObject);<br> private<br> { Private declarations }<br> public<br> { Public declarations }<br> end;<br> <br> var<br> Form1: TForm1;<br> InstallHook: function (SWindow: THandle):Boolean;stdcall;<br> UnHook: procedure;stdcall;<br> implementation<br> {$R *.dfm}<br> procedure TForm1.Button1Click(Sender: TObject);<br> var<br> ModuleHandle: THandle;<br> TmpWndHandle: THandle;<br> begin<br> TmpWndHandle := 0;<br> TmpWndHandle := FindWindow(nil, '目标窗口的标题');<br> if not isWindow(TmpWndHandle) then<br> begin<br> MessageBox(self.Handle, '没有找到窗口', '!!!', MB_OK);<br> exit;<br> end;<br> ModuleHandle := LoadLibrary('Hook.dll');<br> @InstallHook := GetProcAddress(ModuleHandle, 'InstallHook');<br> @UnHook := GetProcAddress(ModuleHandle, 'UnHook');<br> if InstallHook(FindWindow(nil, 'Untitled')) then<br> ShowMessage('Hook OK');<br> end;<br> procedure TForm1.Button2Click(Sender: TObject);<br> begin<br> UnHook<br> end;<br> end.<br><br> <br> 这段代码讲解;找到winsock 中send和Recv <br>地址来回替换,send和recv是封包发送,接受的函数,其中参数,buf为其中的数据封包,就是本段程序要的,自己定义myseng和myrecv来替换。处理数据就在自己定义的的这两个函数中,这个方法听说过,没想到这么简单,作者厉害呀!在myseng和myrecv中加如下代码就可以看到发送出去什么受到什么了。 <br> var tmp:string; begin setlength(tmp,len); <br> move(buf,tmp[1],len); showmessage(tmp); end; <br> 关于hook函数就不讲了相信,能把文看完的,就回略知一 二 如果你知道怎么解密网络游戏封包的话,游戏外挂的原理你就明白了。