Information
The cramfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems. A cramfs image can be used without having to first decompress the image.
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 with a line that reads install cramfs /bin/false and a line the reads blacklist cramfs.
Example:
# printf 'install cramfs /bin/false
blacklist cramfs
' >> /etc/modprobe.d/cramfs.conf
Run the following command to unload the cramfs module:
# modprobe -r cramfs
Additional Information:
NIST SP 800-53 Rev. 5:
CM-7