In Linux to disable shell access to a vsftp user:

 Add /bin/false to /etc/shells directory
 make /bin/false as the default shell for the user

proftp

Setting up FTP accounts for users using ProFTPd

Sample configuration file

ServerName     "DC7700 FTP server"
ServerIdent    on "DC7700 FTP Server ready."
ServerAdmin    root@localhost
ServerType     standalone
DefaultServer  on
AccessGrantMsg "User %u logged in."
DeferWelcome   off

# Do not perform ident nor DNS lookups (hangs when the port is filtered)
IdentLookups   off
UseReverseDNS  off

# Port 21 is the standard FTP port.
Port 21

# Umask 022 is a good standard umask to prevent new dirs and files from being group and world writable.
Umask  022

# Default to show dot files in directory listings
ListOptions   "-a"

# To prevent DoS attacks, set the maximum number of child processes to 30.
MaxInstances 30

# Allow to resume not only the downloads but the uploads too
AllowRetrieveRestart  on
AllowStoreRestart     on

# Set the user and group that the server normally runs at.
User nobody
Group nogroup

# chroot all users of group users to their home directory
# and not a member of adm 
DefaultRoot ~ users,!adm

# disable root login and require a valid shell (from /etc/shells)
RootLogin off
RequireValidShell on

# Normally, we want users to do a few things
<Global>
  <Limit ALL SITE_CHMOD>
    AllowAll
  </Limit>
</Global>

# grant login only for members of the group ftpuser
<Limit LOGIN>
DenyGroup !ftpuser
</Limit>

# to set a different umask for directory /ftp/special from fefault 022
<Directory /ftp/special>
AllowOverwrite   on
Umask            002 002
</Directory>

# This is where we want to put the pid file
ScoreboardFile   /var/run/proftpd.score

# Define the log formats
LogFormat                       default "%h %l %u %t \"%r\" %s %b"
LogFormat                       auth    "%v [%P] %h %t \"%r\" %s"

# activate logging 
# every login
ExtendedLog /var/log/proftpd/auth.log AUTH auth

# file/dir access
ExtendedLog /var/log/proftpd/access.log WRITE,READ write

# for paranoid (big logfiles!)
#ExtendedLog /var/log/proftpd/paranoid.log ALL default

# Configuration for mod_ban
<IfModule mod_ban.c>
  BanEngine on
  BanLog /var/log/proftpd/ban.log
  BanTable /var/run/proftpd/ban.tab

# If the same client reaches the MaxLoginAttempts limit 2 times within 10 minutes, 
#automatically add a ban for that client that will expire after one hour.

  BanOnEvent MaxLoginAttempts 2/00:10:00 01:00:00

# Allow the FTP admin to manually add/remove bans 

 BanControlsACLs all allow user ftpadm
</IfModule>

Additional Useful configurations which can be added

# An upload directory that allows storing files but not retrieving or creating directories.
<Directory uploads/*>
AllowOverwrite no
   <Limit READ>
       DenyAll
   </Limit>

   <Limit STOR>
      AllowAll
   </Limit>
</Directory>

# A basic anonymous configuration, with an upload directory.
<Anonymous ~ftp>
  User  ftp
  Group ftp
  AccessGrantMsg "Anonymous login ok, restrictions apply."

# We want clients to be able to login with "anonymous" as well as "ftp"
  UserAlias  anonymous ftp

# Limit the maximum number of anonymous logins
  MaxClients  10 "Sorry, max %m users -- try again later"

# Put the user into /pub right after login
  DefaultChdir  /pub

# We want 'welcome.msg' displayed at login, '.message' displayed in
# each newly chdired directory and tell users to read README* files.
    DisplayLogin                 /welcome.msg
    DisplayFirstChdir            .message
    DisplayReadme                        README*

# Some more cosmetic and not vital stuff
    DirFakeUser                  on ftp
    DirFakeGroup                 on ftp

# Limit WRITE everywhere in the anonymous chroot
    <Limit WRITE SITE_CHMOD>
      DenyAll
    </Limit>
</Anonymous>

http://www.proftpd.org/docs/directives/linked/configuration.html