The squashfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems (similar to cramfs). A squashfs image can be used without having to first decompress the image. Removing support for unneeded filesystem types reduces the local attack surface of the system. If this filesystem type is not needed, disable it.
Edit or create the file /etc/modprobe.d/CIS.conf and add the following line: install squashfs /bin/true Run the following command to unload the squashfs module: # rmmod squashfs