Local users in VSFTPD can't have a a false shell (was, VSFTPD problems with all logins anonymous or PAM)
April 2010.
# ln -s /bin/false /sbin/nologin
# echo /sbin/nologin >>/etc/shells
- and then specify /sbin/nologin as the shell for those users.
Source:
* https://lists.ubuntu.com/archives/ubuntu-users/2006-October/096043.html