Find a weird user on the SMTP server.

They're not one of these:

bin
daemon
ftp
games
guest
halt
lp
mail
man
news
nobody
ntp
operator
postmaster
postfix
root
ROOT
shutdown
sshd
sync
uucp
www

(hint: /usr/share/wordlists/metasploit/unix_users.txt is a good wordlist)

Box: luhack-enum-0