To configure the system to prevent the squashfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/squashfs.conf:
install squashfs /bin/true
This effectively prevents usage of this uncommon filesystem.
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.