利用DLL劫持内存补丁技术注入

     当一个可执行文件运行时，Windows加载器将可执行模块映射到进程的地址空间中，加载器分析可执行模块的输入表，并设法找出任何需要的DLL，并将它们映射到进程的地址空间中。由于输入表中只包含DLL名而没有它的路径名，因此加载程序必须在磁盘上搜索DLL文件。首先会尝试从当前程序所在的目录加载DLL，如果没找到，则在Windows系统目录查找，最后是在环境变量中列出的各个目录下查找。利用这个特点，先伪造一个系统同名的DLL，提供同样的输出表，每个输出函数转向真正的系统DLL。程序调用系统DLL时会先调用当前目录下伪造的DLL，完成相关功能后，再跳到系统DLL同名函数里执行。这个过程用个形象的词来描述就是系统DLL被劫持
（hijack）了。
示例DELPHI源码：

Library USP10;  
uses
Windows,  
SysUtils,  
Classes;  
{$R *.res}
ModHandle: Cardinal;  
POldLpkPresent: Pointer;  
POldScriptApplyDigitSubstitution: Pointer;  
POldScriptApplyLogicalWidth: Pointer;  
POldScriptBreak: Pointer;  
POldScriptCPtoX: Pointer;  
POldScriptCacheGetHeight: Pointer;  
POldScriptFreeCache: Pointer;  
POldScriptGetCMap: Pointer;  
POldScriptGetFontProperties: Pointer;  
POldScriptGetGlyphABCWidth: Pointer;  
POldScriptGetLogicalWidths: Pointer;  
POldScriptGetProperties: Pointer;  
POldScriptIsComplex: Pointer;  
POldScriptItemize: Pointer;  
POldScriptJustify: Pointer;  
POldScriptLayout: Pointer;  
POldScriptPlace: Pointer;  
POldScriptRecordDigitSubstitution: Pointer;  
POldScriptShape: Pointer;  
POldScriptStringAnalyse: Pointer;  
POldScriptStringCPtoX: Pointer;  
POldScriptStringFree: Pointer;  
POldScriptStringGetLogicalWidths: Pointer;  
POldScriptStringGetOrder: Pointer;  
POldScriptStringOut: Pointer;  
POldScriptStringValidate: Pointer;  
POldScriptStringXtoCP: Pointer;  
POldScriptString_pLogAttr: Pointer;  
POldScriptString_pSize: Pointer;  
POldScriptString_pcOutChars: Pointer;  
POldScriptTextOut: Pointer;  
POldScriptXtoCP: Pointer;  
POldUspAllocCache: Pointer;  
POldUspAllocTemp: Pointer;  
POldUspFreeMem: Pointer;  
procedure LpkPresent; asm jmp POldLpkPresent end;  
procedure ScriptApplyDigitSubstitution; asm jmp POldScriptApplyDigitSubstitution end;  
procedure ScriptApplyLogicalWidth; asm jmp POldScriptApplyLogicalWidth end;  
procedure ScriptBreak; asm jmp POldScriptBreak end;  
procedure ScriptCPtoX; asm jmp POldScriptCPtoX end;  
procedure ScriptCacheGetHeight; asm jmp POldScriptCacheGetHeight end;  
procedure ScriptFreeCache; asm jmp POldScriptFreeCache end;  
procedure ScriptGetCMap; asm jmp POldScriptGetCMap end;  
procedure ScriptGetFontProperties; asm jmp POldScriptGetFontProperties end;  
procedure ScriptGetGlyphABCWidth; asm jmp POldScriptGetGlyphABCWidth end;  
procedure ScriptGetLogicalWidths; asm jmp POldScriptGetLogicalWidths end;  
procedure ScriptGetProperties; asm jmp POldScriptGetProperties end;  
procedure ScriptIsComplex; asm jmp POldScriptIsComplex end;  
procedure ScriptItemize; asm jmp POldScriptItemize end;  
procedure ScriptJustify; asm jmp POldScriptJustify end;  
procedure ScriptLayout; asm jmp POldScriptLayout end;  
procedure ScriptPlace; asm jmp POldScriptPlace end;  
procedure ScriptRecordDigitSubstitution; asm jmp POldScriptRecordDigitSubstitution end;  
procedure ScriptShape; asm jmp POldScriptShape end;  
procedure ScriptStringAnalyse; asm jmp POldScriptStringAnalyse end;  
procedure ScriptStringCPtoX; asm jmp POldScriptStringCPtoX end;  
procedure ScriptStringFree; asm jmp POldScriptStringFree end;  
procedure ScriptStringGetLogicalWidths; asm jmp POldScriptStringGetLogicalWidths end;  
procedure ScriptStringGetOrder; asm jmp POldScriptStringGetOrder end;  
procedure ScriptStringOut; asm jmp POldScriptStringOut end;  
procedure ScriptStringValidate; asm jmp POldScriptStringValidate end;  
procedure ScriptStringXtoCP; asm jmp POldScriptStringXtoCP end;  
procedure ScriptString_pLogAttr; asm jmp POldScriptString_pLogAttr end;  
procedure ScriptString_pSize; asm jmp POldScriptString_pSize end;  
procedure ScriptString_pcOutChars; asm jmp POldScriptString_pcOutChars end;  
procedure ScriptTextOut; asm jmp POldScriptTextOut end;  
procedure ScriptXtoCP; asm jmp POldScriptXtoCP end;  
procedure UspAllocCache; asm jmp POldUspAllocCache end;  
procedure UspAllocTemp; asm jmp POldUspAllocTemp end;  
procedure UspFreeMem; asm jmp POldUspFreeMem end;  

exports
LpkPresent,  
ScriptApplyDigitSubstitution,  
ScriptApplyLogicalWidth,  
ScriptBreak,  
ScriptCPtoX,  
ScriptCacheGetHeight,  
ScriptFreeCache,  
ScriptGetCMap,  
ScriptGetFontProperties,  
ScriptGetGlyphABCWidth,  
ScriptGetLogicalWidths,  
ScriptGetProperties,  
ScriptIsComplex,  
ScriptItemize,  
ScriptJustify,  
ScriptLayout,  
ScriptPlace,  
ScriptRecordDigitSubstitution,  
ScriptShape,  
ScriptStringAnalyse,  
ScriptStringCPtoX,  
ScriptStringFree,  
ScriptStringGetLogicalWidths,  
ScriptStringGetOrder,  
ScriptStringOut,  
ScriptStringValidate,  
ScriptStringXtoCP,  
ScriptString_pLogAttr,  
ScriptString_pSize,  
ScriptString_pcOutChars,  
ScriptTextOut,  
ScriptXtoCP,  
UspAllocCache,  
UspAllocTemp,  
UspFreeMem;  
begin
ModHandle:= LoadLibrary('C:\WINDOWS\system32\usp10.dll');  
if ModHandle > 0 then
begin
   POldLpkPresent:= GetProcAddress(ModHandle, 'LpkPresent');  
   POldScriptApplyDigitSubstitution:= GetProcAddress(ModHandle,'ScriptApplyDigitSubstitution');  
   POldScriptApplyLogicalWidth:= GetProcAddress(ModHandle,'ScriptApplyLogicalWidth');  
   POldScriptBreak:= GetProcAddress(ModHandle, 'ScriptBreak');  
   POldScriptCPtoX:= GetProcAddress(ModHandle, 'ScriptCPtoX');  
   POldScriptCacheGetHeight:= GetProcAddress(ModHandle, 'ScriptCacheGetHeight');  
   POldScriptFreeCache:= GetProcAddress(ModHandle, 'ScriptFreeCache');  
   POldScriptGetCMap:= GetProcAddress(ModHandle, 'ScriptGetCMap');  
   POldScriptGetFontProperties:= GetProcAddress(ModHandle,'ScriptGetFontProperties');  
   POldScriptGetGlyphABCWidth:= GetProcAddress(ModHandle, 'ScriptGetGlyphABCWidth');  
   POldScriptGetLogicalWidths:= GetProcAddress(ModHandle, 'ScriptGetLogicalWidths');  
   POldScriptGetProperties:= GetProcAddress(ModHandle, 'ScriptGetProperties');  
   POldScriptIsComplex:= GetProcAddress(ModHandle, 'ScriptIsComplex');  
   POldScriptItemize:= GetProcAddress(ModHandle, 'ScriptItemize');  
   POldScriptJustify:= GetProcAddress(ModHandle, 'ScriptJustify');  
   POldScriptLayout:= GetProcAddress(ModHandle, 'ScriptLayout');  
   POldScriptPlace:= GetProcAddress(ModHandle, 'ScriptPlace');  
   POldScriptRecordDigitSubstitution:= GetProcAddress(ModHandle,'ScriptRecordDigitSubstitution');  
   POldScriptShape:= GetProcAddress(ModHandle, 'ScriptShape');  
   POldScriptStringAnalyse:= GetProcAddress(ModHandle, 'ScriptStringAnalyse');  
   POldScriptStringCPtoX:= GetProcAddress(ModHandle, 'ScriptStringCPtoX');  
   POldScriptStringFree:= GetProcAddress(ModHandle, 'ScriptStringFree');  
   POldScriptStringGetLogicalWidths:= GetProcAddress(ModHandle,'ScriptStringGetLogicalWidths');  
   POldScriptStringGetOrder:= GetProcAddress(ModHandle, 'ScriptStringGetOrder');  
   POldScriptStringOut:= GetProcAddress(ModHandle, 'ScriptStringOut');  
   POldScriptStringValidate:= GetProcAddress(ModHandle, 'ScriptStringValidate');  
   POldScriptStringXtoCP:= GetProcAddress(ModHandle, 'ScriptStringXtoCP');  
   POldScriptString_pLogAttr:= GetProcAddress(ModHandle, 'ScriptString_pLogAttr');  
   POldScriptString_pSize:= GetProcAddress(ModHandle, 'ScriptString_pSize');  
   POldScriptString_pcOutChars:= GetProcAddress(ModHandle,'ScriptString_pcOutChars');  
   POldScriptTextOut:= GetProcAddress(ModHandle, 'ScriptTextOut');  
   POldScriptXtoCP:= GetProcAddress(ModHandle, 'ScriptXtoCP');  
   POldUspAllocCache:= GetProcAddress(ModHandle, 'UspAllocCache');  
   POldUspAllocTemp:= GetProcAddress(ModHandle, 'UspAllocTemp');  
   POldUspFreeMem:= GetProcAddress(ModHandle, 'UspFreeMem');  
end;  
begin
//添加自己的补丁内容！
end;  
end.