Enumeration
sudo nmap -sC -sV -p 21 $IP
21/tcp open ftp vsftpd 2.0.8 or later
| ftp-anon: Anonymous FTP login allowed (FTP code 230)
Hydra
hydra -t 4 -l <USER> -P /usr/share/wordlists/rockyou.txt -vV $IP ftp
sudo nmap -sC -sV -p 21 $IP
21/tcp open ftp vsftpd 2.0.8 or later
| ftp-anon: Anonymous FTP login allowed (FTP code 230)
hydra -t 4 -l <USER> -P /usr/share/wordlists/rockyou.txt -vV $IP ftp