拦截其它程序的网络数据封包

绝地灬酷狼 2021-12-15 13:25 327阅读 0赞

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, 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.

\---------------------------------------------------------------------------------------------  
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.

转载于:https://www.cnblogs.com/rogee/archive/2011/06/11/2078316.html