截取程序的网络封包（Delphi Hook API）（该日志是转载的）

原作者: [db:作者] 来自: [db:来源] 收藏邀请

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:


  1 library Hook; 
  2 
  3 uses 
  4 SysUtils, 
  5 windows, 
  6 Messages, 
  7 APIHook in 'APIHook.pas'; 
  8 
  9 type 
 10 PData = ^TData; 
 11 TData = record 
 12 Hook: THandle; 
 13 Hooked: Boolean; 
 14 end; 
 15 
 16 var 
 17 DLLData: PData; 
 18 
 19 {------------------------------------} 
 20 {过程名:HookProc 
 21 {过程功能:HOOK过程 
 22 {过程参数:nCode, wParam, lParam消息的相 
 23 { 关参数 
 24 {------------------------------------} 
 25 procedure HookProc(nCode, wParam, lParam: LongWORD);stdcall; 
 26 begin 
 27 if not DLLData^.Hooked then 
 28 begin 
 29 HookAPI; 
 30 DLLData^.Hooked := True; 
 31 end; 
 32 //调用下一个Hook 
 33 CallNextHookEx(DLLData^.Hook, nCode, wParam, lParam); 
 34 end; 
 35 
 36 
 37 {------------------------------------} 
 38 {函数名:InstallHook 
 39 {函数功能:在指定窗口上安装HOOK 
 40 {函数参数:sWindow:要安装HOOK的窗口 
 41 {返回值:成功返回TRUE,失败返回FALSE 
 42 {------------------------------------} 
 43 function InstallHook(SWindow: LongWORD):Boolean;stdcall; 
 44 var 
 45 ThreadID: LongWORD; 
 46 begin 
 47 Result := False; 
 48 DLLData^.Hook := 0; 
 49 ThreadID := GetWindowThreadProcessId(sWindow, nil); 
 50 //给指定窗口挂上钩子 
 51 DLLData^.Hook := SetWindowsHookEx(WH_GETMESSAGE, @HookProc, Hinstance, ThreadID); 
 52 if DLLData^.Hook > 0 then 
 53 Result := True //是否成功HOOK 
 54 else 
 55 exit; 
 56 end; 
 57 
 58 {------------------------------------} 
 59 {过程名:UnHook 
 60 {过程功能:卸载HOOK 
 61 {过程参数:无 
 62 {------------------------------------} 
 63 procedure UnHook;stdcall; 
 64 begin 
 65 UnHookAPI; 
 66 //卸载Hook 
 67 UnhookWindowsHookEx(DLLData^.Hook); 
 68 end; 
 69 
 70 {------------------------------------} 
 71 {过程名:DLL入口函数 
 72 {过程功能:进行DLL初始化,释放等 
 73 {过程参数:DLL状态 
 74 {------------------------------------} 
 75 procedure MyDLLHandler(Reason: Integer); 
 76 var 
 77 FHandle: LongWORD; 
 78 begin 
 79 case Reason of 
 80 DLL_PROCESS_ATTACH: 
 81 begin //建立文件映射,以实现DLL中的全局变量 
 82 FHandle := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE, 0, $ffff, 'MYDLLDATA'); 
 83 if FHandle = 0 then 
 84 if GetLastError = ERROR_ALREADY_EXISTS then 
 85 begin 
 86 FHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, 'MYDLLDATA'); 
 87 if FHandle = 0 then Exit; 
 88 end else Exit; 
 89 DLLData := MapViewOfFile(FHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0); 
 90 if DLLData = nil then 
 91 CloseHandle(FHandle); 
 92 end; 
 93 DLL_PROCESS_DETACH: 
 94 begin 
 95 if Assigned(DLLData) then 
 96 begin 
 97 UnmapViewOfFile(DLLData); 
 98 DLLData := nil; 
 99 end; 
100 end; 
101 end; 
102 end; 
103 
104 {$R *.res} 
105 exports 
106 InstallHook, UnHook, HookProc; 
107 
108 begin 
109 DLLProc := @MyDLLHandler; 
110 MyDLLhandler(DLL_PROCESS_ATTACH); 
111 DLLData^.Hooked := False; 
112 end. 
113 
114 ---------------------------------------------------------------------------------------- 
115 APIHook.Pas的代码: 
116 
117 unit APIHook; 
118 
119 interface 
120 
121 uses 
122 SysUtils, 
123 Windows, WinSock; 
124 
125 type 
126 //要HOOK的API函数定义 
127 TSockProc = function (s: TSocket; var Buf; len, flags: Integer): Integer; stdcall; 
128 
129 PJmpCode = ^TJmpCode; 
130 TJmpCode = packed record 
131 JmpCode: BYTE; 
132 Address: TSockProc; 
133 MovEAX: Array [0..2] of BYTE; 
134 end; 
135 
136 //--------------------函数声明--------------------------- 
137 procedure HookAPI; 
138 procedure UnHookAPI; 
139 
140 var 
141 OldSend, OldRecv: TSockProc; //原来的API地址 
142 JmpCode: TJmpCode; 
143 OldProc: array [0..1] of TJmpCode; 
144 AddSend, AddRecv: pointer; //API地址 
145 TmpJmp: TJmpCode; 
146 ProcessHandle: THandle; 
147 implementation 
148 
149 {---------------------------------------} 
150 {函数功能:Send函数的HOOK 
151 {函数参数:同Send 
152 {函数返回值:integer 
153 {---------------------------------------} 
154 function MySend(s: TSocket; var Buf; len, flags: Integer): Integer; stdcall; 
155 var 
156 dwSize: cardinal; 
157 begin 
158 //这儿进行发送的数据处理 
159 MessageBeep(1000); //简单的响一声 
160 //调用直正的Send函数 
161 WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize); 
162 Result := OldSend(S, Buf, len, flags); 
163 JmpCode.Address := @MySend; 
164 WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, dwSize); 
165 end; 
166 
167 {---------------------------------------} 
168 {函数功能:Recv函数的HOOK 
169 {函数参数:同Recv 
170 {函数返回值:integer 
171 {---------------------------------------} 
172 function MyRecv(s: TSocket; var Buf; len, flags: Integer): Integer; stdcall; 
173 var 
174 dwSize: cardinal; 
175 begin 
176 //这儿进行接收的数据处理 
177 MessageBeep(1000); //简单的响一声 
178 //调用直正的Recv函数 
179 WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize); 
180 Result := OldRecv(S, Buf, len, flags); 
181 JmpCode.Address := @MyRecv; 
182 WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, dwSize); 
183 end; 
184 
185 {------------------------------------} 
186 {过程功能:HookAPI 
187 {过程参数:无 
188 {------------------------------------} 
189 procedure HookAPI; 
190 var 
191 DLLModule: THandle; 
192 dwSize: cardinal; 
193 begin 
194 ProcessHandle := GetCurrentProcess; 
195 DLLModule := LoadLibrary('ws2_32.dll'); 
196 AddSend := GetProcAddress(DLLModule, 'send'); //取得API地址 
197 AddRecv := GetProcAddress(DLLModule, 'recv'); 
198 JmpCode.JmpCode := $B8; 
199 JmpCode.MovEAX[0] := $FF; 
200 JmpCode.MovEAX[1] := $E0; 
201 JmpCode.MovEAX[2] := 0; 
202 ReadProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize); 
203 JmpCode.Address := @MySend; 
204 WriteProcessMemory(ProcessHandle, AddSend, @JmpCode, 8, dwSize); //修改Send入口 
205 ReadProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize); 
206 JmpCode.Address := @MyRecv; 
207 WriteProcessMemory(ProcessHandle, AddRecv, @JmpCode, 8, dwSize); //修改Recv入口 
208 OldSend := AddSend; 
209 OldRecv := AddRecv; 
210 end; 
211 
212 {------------------------------------} 
213 {过程功能:取消HOOKAPI 
214 {过程参数:无 
215 {------------------------------------} 
216 procedure UnHookAPI; 
217 var 
218 dwSize: Cardinal; 
219 begin 
220 WriteProcessMemory(ProcessHandle, AddSend, @OldProc[0], 8, dwSize); 
221 WriteProcessMemory(ProcessHandle, AddRecv, @OldProc[1], 8, dwSize); 
222 end; 
223 
224 end. 
225 
226 --------------------------------------------------------------------------------------------- 
227 编译这个DLL后,再新建一个程序调用这个DLL的InstallHook并传入目标进程的主窗口句柄就可: 
228 unit fmMain; 
229 
230 interface 
231 
232 uses 
233 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
234 Dialogs, StdCtrls; 
235 
236 type 
237 TForm1 = class(TForm) 
238 Button1: TButton; 
239 Button2: TButton; 
240 Edit1: TEdit; 
241 procedure Button1Click(Sender: TObject); 
242 procedure Button2Click(Sender: TObject); 
243 private 
244 { Private declarations } 
245 public 
246 { Public declarations } 
247 end; 
248 
249 var 
250 Form1: TForm1; 
251 InstallHook: function (SWindow: THandle):Boolean;stdcall; 
252 UnHook: procedure;stdcall; 
253 implementation 
254 
255 {$R *.dfm} 
256 
257 procedure TForm1.Button1Click(Sender: TObject); 
258 var 
259 ModuleHandle: THandle; 
260 TmpWndHandle: THandle; 
261 begin 
262 TmpWndHandle := 0; 
263 TmpWndHandle := FindWindow(nil, '目标窗口的标题'); 
264 if not isWindow(TmpWndHandle) then 
265 begin 
266 MessageBox(self.Handle, '没有找到窗口', '!!!', MB_OK); 
267 exit; 
268 end; 
269 ModuleHandle := LoadLibrary('Hook.dll'); 
270 @InstallHook := GetProcAddress(ModuleHandle, 'InstallHook'); 
271 @UnHook := GetProcAddress(ModuleHandle, 'UnHook'); 
272 if InstallHook(FindWindow(nil, 'Untitled')) then 
273 ShowMessage('Hook OK'); 
274 end; 
275 
276 procedure TForm1.Button2Click(Sender: TObject); 
277 begin 
278 UnHook 
279 end; 
280 
281 end. 
282