GlobaLevel
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ASP.NET - Concerned about File upload security
I am using the following code to upload files ...but I am concerned about security in the sense that its available to the public and I want to be sure only certain extentions can be user...txt or .csv...they are upload address info..but if a hacker comes along...they could upload a file that take over the system..any code to protect ..ideas?
FYI..the whole site has SSL on it..if that makes a difference...
FYI..the whole site has SSL on it..if that makes a difference...
<html>
<head>
<script language="VB" runat="server">
Sub Button1_Click(sender As Object, e As EventArgs)
if FileUpLoad1.HasFile
'Uncomment this line to Save the uploaded file
'FileUpLoad1.SaveAs("C:\SomePhysicalPath" & FileUpLoad1.Filename)
Label1.Text = "Received " & FileUpLoad1.FileName & " Content Type " & FileUpLoad1.PostedFile.ContentType & " Length " & FileUpLoad1.PostedFile.ContentLength
else
Label1.Text = "No uploaded file"
end if
end sub
</script>
</head>
<body>
<h3><font face="Verdana">File Upload</font></h3>
<form runat=server>
<asp:FileUpLoad id="FileUpLoad1" AlternateText="You cannot upload files" runat="server" />
<asp:Button id="Button1" Text="Upload" OnClick="Button1_Click" runat="server" />
<asp:Label id="Label1" runat="server" />
</form>
</body>
</html>
ASKER
this is good stuff..thanks...I put an instr code piece b4 the file.upload puts the file on the server to scan for extentions.....
I like the <httpRuntime> ..but I donthave that in my web.config...can I add that? even though its not in there? My users have to ave an account b4 they can upload..but im still being extra cautious...
I like the <httpRuntime> ..but I donthave that in my web.config...can I add that? even though its not in there? My users have to ave an account b4 they can upload..but im still being extra cautious...
ASKER CERTIFIED SOLUTION
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http://msdn.microsoft.com/en-us/library/aa479405.aspx
It gives you some example on determining the file size and type before uploading.