Information
USB storage provides a means to transfer and store files insuring persistence and availability of the files independent of network connection status. Its popularity and utility has led to USB-based malware being a simple and common means for network infiltration and a first step to establishing a persistent threat within a networked environment.
Rationale:
Restricting USB access on the system will decrease the physical attack surface for a device and diminish the possible vectors to introduce malware.
Solution
Edit or create a file in the /etc/modprobe.d/ directory ending in .conf
Example: vim /etc/modprobe.d/usb_storage.conf
and add the following line:
install usb-storage /bin/true
Run the following command to unload the usb-storage module:
rmmod usb-storage
Additional Information:
An alternative solution to disabling the usb-storage module may be found in USBGuard.
Use of USBGuard and construction of USB device policies should be done in alignment with site policy.