1.1.1.7 Ensure mounting of FAT filesystems is limited - modprobe

Warning! Audit Deprecated

This audit has been deprecated and will be removed in a future update.

View Next Audit Version

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.

Rationale:

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 in .conf
Example: vi /etc/modprobe.d/vfat.conf

install vfat /bin/true

Run the following command to unload the vfat module:

# rmmod vfat

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.

See Also

https://workbench.cisecurity.org/files/2873

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, CSCv7|5.1

Plugin: Unix

Control ID: c7c1da4c51d12222f4a8b84010b169c5b02e0135cde4bbc72b8b27baf90ad0c7