I've just stumbled into this bug on 14.04.1. Worked around by commenting out "auth required pam_shells.so" in /etc/pam.d/vsftpd and restarting vsftpd as mentioned in 869684.
I've just stumbled into this bug on 14.04.1. Worked around by commenting out "auth required pam_shells.so" in /etc/pam.d/vsftpd and restarting vsftpd as mentioned in 869684.