Information
The FAT filesystem format is primarily used on older windows systems and portable USB drives or flash modules. It comes in three types FAT12 FAT16 and FAT32 all of which are supported by the vfat kernel module.
Removing support for unneeded filesystem types reduces the local attack surface of the system. If this filesystem type is not needed, disable it.
Solution
Edit or create a file in the /etc/modprobe.d/ directory ending inconf and add the following lines:
Example: vim /etc/modprobe.d/fat.conf
install fat /bin/true
install vfat /bin/true
install msdos /bin/true
Run the following commands to unload the msdos vfat and fat modules:
# modprobe -r msdos
# modprobe -r vfat
# modprobe -r fat
Impact:
The FAT filesystem format is used by UEFI systems for the EFI boot partition. Disabling the vfat module can prevent boot on UEFI systems.
FAT filesystems are often used on portable USB sticks and other flash media which are commonly used to transfer files between workstations, removing VFAT support may prevent the ability to transfer files in this way.
Item Details
Category: CONFIGURATION MANAGEMENT, SYSTEM AND SERVICES ACQUISITION
References: 800-53|CM-1, 800-53|CM-2, 800-53|CM-6, 800-53|CM-7, 800-53|CM-7(1), 800-53|CM-9, 800-53|SA-3, 800-53|SA-8, 800-53|SA-10, CSCv7|5.1
Control ID: 8bbd8ed6ee160de928f61a060f3c7881ac85369cc7c3aa03ec86aa1949774ebc