asp 判断上传文件中是否存在危险代码

<% 
function CheckFileContent(FileName) 
dim ClientFile,ClientText,ClientContent,DangerString,DSArray,AttackFlag,k 
set ClientFile=Server.CreateObject("Scripting.FileSystemObject") 
set ClientText=ClientFile.OpenTextFile(Server.MapPath(FileName),1) 
ClientContent=LCase(ClientText.ReadAll) 
set ClientText=nothing 
set ClientFile=nothing 
AttackFlag=false 
DangerString=".getfolder|.createfolder|.deletefolder|.createdirectory|.deletedirectory|.saveas|wscript.shell|script.encode|server.|.createobject|execute|activexobject|language=|include|filesystemobject|shell.application" 
DSArray=split(DangerString,"|") 

for k=0 to UBound(DSArray) 

if InStr(ClientContent,DSArray(k))>0 then '判断文件内容中是否包含有危险的操作字符，如有，则必须删除该文件。 
AttackFlag=true 
exit for 
end if 

next 

CheckFileContent=AttackFlag 
end function 

If CheckFileContent("0.jpg")=true then 
Response.Write "危险" 
else 
Response.Write "安全" 
end if 
%>