1.1.1.6 Ensure mounting of squashfs filesystems is disabled - lsmod

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 a file in the /etc/modprobe.d/ directory ending in .conf
Example: vim /etc/modprobe.d/squashfs.conf
and add the following line:

install squashfs /bin/true

Run the following command to unload the squashfs module:

# rmmod squashfs

See Also

https://workbench.cisecurity.org/files/2420