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
%>