Something

Connected to localhost (127.0.0.1).
220 (vsFTPd 2.0.5)
Name (localhost:pablo): config
331 Please specify the password.
Password:
500 OOPS: cannot locate user entry:config
Login failed.
ftp> quit



==> /var/log/secure <==
Jan 30 14:12:08 nb020 vsftpd: pam_warn(vsftpd:setcred): function=[pam_sm_setcred] service=[vsftpd] terminal=[ftp] user=[test] ruser=[test] rhost=[nb020]
Jan 30 14:13:27 nb020 vsftpd: pam_warn(vsftpd:auth): function=[pam_sm_authenticate] service=[vsftpd] terminal=[ftp] user=[config] ruser=[config] rhost=[nb020]
Jan 30 14:13:27 nb020 vsftpd: pam_warn(vsftpd:auth): function=[pam_sm_authenticate] service=[vsftpd] terminal=[ftp] user=[test] ruser=[test] rhost=[nb020]
Jan 30 14:13:27 nb020 vsftpd: pam_warn(vsftpd:account): function=[pam_sm_acct_mgmt] service=[vsftpd] terminal=[ftp] user=[test] ruser=[test] rhost=[nb020]
Jan 30 14:13:27 nb020 vsftpd: pam_warn(vsftpd:setcred): function=[pam_sm_setcred] service=[vsftpd] terminal=[ftp] user=[test] ruser=[test] rhost=[nb020]