Vulnerability Discussion

USB mass storage permits easy introduction of unknown devices, thereby facilitating malicious activity.

Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163

Check

Verify the operating system disables the ability to load the USB Storage kernel module.

$ sudo grep -r usb-storage /etc/modprobe.d/* | grep -i "/bin/false"
install usb-storage /bin/false

If the command does not return any output, or the line is commented out, and use of USB Storage is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Verify the operating system disables the ability to use USB mass storage devices.

Check to see if USB mass storage is disabled with the following command:

$ sudo grep usb-storage /etc/modprobe.d/* | grep -i "blacklist"
blacklist usb-storage

If the command does not return any output or the output is not "blacklist usb-storage" and use of USB storage devices is not documented with the ISSO as an operational requirement, this is a finding.

Fix

Configure the operating system to disable the ability to use the USB Storage kernel module and the ability to use USB mass storage devices.

Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf":

install usb-storage /bin/false
blacklist usb-storage

Reboot the system for the settings to take effect.