Medusa
Medusa (0.6k β) is an open-source tool used to brute force network services passwords such as FTP.
$ sudo apt install medusa
$ medusa -u username -P passwords.lst -h IP -M ftp
$ medusa -U users.lst -P passwords.lst -h IP -M ftp
$ medusa [...] -n port # port to use
$ medusa [...] -t 4 # number of threads
$ medusa [...] -L # test all username for each password