Information
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.
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 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