Looking for module which will put ProFTPD brute-forcing ip address into hosts.deny. Say if 3 times password was incorrect, ban it from server, preventing to try other services.
If your not adverse to installing other tools than you could use something like Fail2Ban
Have a look at http://www.proftpd.org/docs/contrib/mod_ban.html
MaxLoginAttempts 1 <IfModule mod_ban.c> BanEngine on BanLog /var/log/proftpd/ban.log BanTable /var/data//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>
iptables can do this without the need to install any additional software, or reconfigure underlying services.
You can also try BFD which works with both APF and CSF.
See this for an example scenario.