On our machines, we have no need to run ProFTP or any ftp program. But when I tried to get it turned off I had to struggle a bit, because cpanel kept turning it back on!
After tinkering, I think I've learned the complete steps to make ProFTP cease to run. Here they are --
1) To see whether ftp is running, you can use 'ps -aux | grep ftp'.
To stop proftpd running *now*, run /etc/rc.d/init.d/proftpd stop.
To verify it's no longer running, again use 'ps -aux | grep ftp'.
2) There's a checkbox in Service Manager in WHM and it appears to make ProFTP stop running. But it does *not* actually work. This checkbox is effectively broken.
Because every five minutes, cpanel checks to see that some ftp is running, and if not defaults to proftp and starts it up. End of story. Cannot turn off ProFTP from WHM.
(It will *appear* to stop, but if you reboot, or if the next cpanel check comes along, proftp will be started up again.)
3) Removing /etc/rc.d/init.d/proftpd startup script does stop it from running, but generates 288 daily complaining emails from cpanel.
However, removing this file is the only way to stop proftp after reboots, so it must be removed. If you might *ever* use ftp again, then you'll want to keep this file somewhere.
4) To stop cpanel's checking (and complaining), you must also remove /etc/chkservd.d/proftpd file. This stops cpanel checking for ftp running. (Likewise, if you might ever use ftp, then you'll want to keep this file somewhere.)
That's it. ProFTP is now not running, will not start up on reboot, and will not be restarted every five minutes by cpanel.