(Applicable to other Linux distributions also)
1. Login as root,
2. Open /etc/modprobe.d/no-usb for edit (create this file if it’s not exists),
3. Append this line to the no-usb file (in step-2) and save it:
install usb-storage /bin/true
Reboot server to enforce change.
To confirm USB mass storage support has disabled, just execute
lsmod | grep -i usb or try plug in USB drive to confirm.